Environmental Fate of Fluorotelomer-Based Acrylate Polymers

Environmental Fate of Fluorotelomer-based Acrylate Polymers

Pablo Jorge Z.Y. Tseng

A thesis submitted in conformity with the requirements for the degree Master of Science Department of Chemistry University of Toronto

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1+1 Canada Environmental Fate of Fluorotelomer-based Acrylate Polymers

Pablo Jorge Zhi Yong Tseng

Master of Science

Department of Chemistry University of Toronto

2009

Abstract

Fluorotelomer (FT)-based acrylate polymers have applications in textile, upholstery, carpet, and apparel and leather industries as components of surface protecting coatings. Currently, there is concern that these polymers may be a potential indirect source of perfluoro-carboxylic acids

(PFCAs) in the environment. To address this concern, the current thesis investigated the lability of the ester linkages of a model FT-based acrylate polymer in two potential environmental compartments: sewage wastewater, and surface waters. The in-house synthesized model FT-based acrylate polymer was characterized by ]H and 19F NMR spectroscopy and MALDl-ToF. Potential degradation products including FT alcohols and PFCAs were analyzed by GC-MS and LC-MS/MS respectively. Also, polymer degradation was monitored by lyF NMR spectroscopy and MALDI-

ToF. Evidence of FT polymer degradation was observed in the hydrolysis and wastewater studies, suggesting that FT-polymer degradation potentially contributes to the PFCA burden in the environment.

ii Acknowledgements

This thesis was made possible by those whom 1 have had the good fortune to cross paths with.

To all the members and support staff of the chemistry department at the University, your tireless efforts have made this Department a success, and my thesis a possibility.

To my colleagues on the 2nd and 3rd floors of LM, and at UTSc, your inspiration and the friendly hallway banter have made my stay at LM memorable and enjoyable. To CB, JC, ADS, DJ, HL,

EM, AM, AR, and CY, my time at the Mabury lab has been rewarding academically and socially.

Since my starting at the lab as a summer student in 2006. you have become more than colleagues, and though time parts us now, we need not despair; the foundations to our lasting friendships have been lain already. To CQ. thank you.

To my committee members Professors Jennifer Murphy and Douglas Stephan, your availability and insight into my research have been a great help to my graduate work. 1 would like to especially thank Professor Scott A. Mabury for unparalleled research guidance, professional support, and camaraderie.

This thesis is dedicated to Science. As a tree in the passage of time, so shall you remain.

iii iv Table of Contents

Abstract ii

Acknowledgements iii

Table of Contents v

List of Figures viii

List of tables x

1 Introduction to Perfluorinated Chemicals 2

1.1 Perfluorinated Carboxylic Acids 2

1.2 Fluorotelomer Alcohols 3

1.3 Fluorotelomer-based polymers 5

1.4 Research Objectives 8

1.5 Literature Cited 10

2 Degradation of Fluorotelomer based Polymers in Wastewaters 14 2.1 Abstract 14

2.2 Introduction 15

2.3 Experimental Section 17

2.3.1 Chemicals 17

2.3.2 Polymer Synthesis , 17

2.3.3 Polymer Characterization 18

2.3.4 Polymer Solubility and Residual Removal 22

2.3.5 Experimental Set-up 24

2.3.6 Vessel Headspace Analysis 27

2.3.7 Vessel Aqueous Medium Analysis , 28

v 2.3.8 Data Analysis 29

2.3.9 Quality Assurance and Control 29

2.4 Results and Discussion 30

2.4.1 Hydrolysis Study 30

2.4.2 Wastewater Study 38

2.5 Environmental Implications 46

2.6 Acknowledgements 46

2.7 Literature Cited 47

Research Directions and Future Considerations 52

3.1 Polymer Synthesis and Characterization 52

3.2 The Degradation of Ruorotelomer Acrylate Polymers in Soils 57

3.2.1 Residual Removal and Polymer Solubility 58

3.2.2 Experimental Set-Up 59

3.3 Thermal and Mechanical Degradation 60

3.4 Future Considerations 63

3.5 Literature Cited 65

Appendix 67

4.1 Section 2.3.4 - Polymer Solubility and Residual Removal 67

4.2 Section 2.3.7 - Vessel Aqueous Medium Analysis 70

4.3 Section 2.4.1 - 8:2 FTOH Evolution 71

4.4 Section 2.4.1 - 19F NMR Spectroscopy Analysis 77

4.5 Section 2.4.1 - MALDI-ToF Analysis 81

4.6 Section 2.4.1 - Hydrolytic Degradation Rates 89

4.7 Section 2.4.2 - Wastewater Sludge Viability Test 90 4.8 Section 2.4.2 - Headspace Analysis 91

4.9 Section 2.4.2 - Aqueous Analysis 92

4.10 Section 3.1 - Polymer Synthesis and Characterization 97

VII List of Figures

Figure 1-1. (a) atmospheric degradation pathway; (b) biodegradation pathway 4

Figure 1-2. (a) 8:2 FT acrylate; (b) 8:2 FT methacrylate 5

Figure 1-3. Ruorotelomer-based polymer synthesis 6

Figure 2-1. Fluorotelomer-based acrylate polymer synthesis 18

Figure 2-2. (a) Schematic of Model Polymer (b) 19F NMR spectrum of polymer 19

Figure 2-3. MALDI Spectrum of synthesized fluorotelomer acrylate based polymer 21

Figure 2-4. GC chromatogram of polymer solution after 30 days of residual purging,

immediately prior to the start of the experiment 23

Figure 2-5. Schematic Diagram of Experimental Set-up for Hydrolysis/Wastewater Studies. 25

Figure 2-6. Evolution of 8:2 FTOH at pHs 4, 6, 8 and 10 31

Figure 2-7. Hydrolytic degradation rates of FT polymer at various pH conditions 37

Figure 2-8. Transformation of 6:2 FTUCA to PFHxA - Viability Test 38

Figure 2-9. 8:2 FTOH evolution in Control Set 2 and Experimental Vessels 39

Figure 2-10. Amounts of 8:2 FTOH metabolites detected in Sample Vessels (a) PFHxA; (b)

PFHpA: (c) PFOA: td) 8:2 FTUCA 41

Figure 3-1. Schematic of New Model Polymer 53

Figure 3-2. MALDI Spectrum of New Model Ruorotelomer acrylate based Polymer 55

Figure 3-3. Summary of the identity of FT acrylate polymer signals 56

Figure 3-4. Proposed mechanism of thermal degradation of 8:2 FT acrylate polymers 61

Figure 3-5. atmospheric oxidation pathway of ethylene thermal degradation product 61

Figure 3-6. Proposed mechanism of FTOH evolution from polymeric thermal degradation... 62

Figure 4-1. Concentration of Polymer in the prepared polymer solution 67

Figure 4-2. I9F NMR spectrum of the lOOppm polymer calibration standard 69 viii Figure 4-3. Comparison of the Hansen and Higgin methods of PFCA extraction 70

Figure 4-4.19F NMR spectrum of hydrolysis Sample Experimental Vessel at Day 0 78

Figure 4-5. 19F NMR spectrum of hydrolysis pH = 4 Experimental Vessel at Day 80 79

Figure 4-6. 19F NMR spectrum of hydrolysis pH = 10 Experimental Vessel at Day 80 80

Figure 4-7. MALDI Spectrum of Polymer in Sample Experimental Vessel at day 0 (I) 81

Figure 4-8. MALDI Spectrum of Polymer in pH =4 Experimental Vessel at day 80 (I) 82

Figure 4-9. MALDI Spectrum of Polymer in pH =6 Experimental Vessel at day 80 (I) 83

Figure 4-10. MALDI Spectrum of Polymer in pH =10 Experimental Vessel at day 80 (I) 84

Figure 4-11. MALDI Spectrum of Polymer in Sample Experimental Vessel at day 0 (II) 85

Figure 4-12. MALDI Spectrum of Polymer in pH = 4 Experimental Vessel at day 80 ill) 86

Figure 4-13. MALDI Spectmm of Polymer in pH = 6 Experimental Vessel at day 80 (II) 87

Figure 4-14. MALDI Spectrum of Polymer in pH = 10 Experimental Vessel at day 80 (II)... 88

Figure 4-15.DSC - Melting and Crystallization Points of newly synthesized polymer 97

Figure 4-16. Repeating Polymeric Units in the Polymer Distribution 98

Figure 4-17. Determination of FT acrylate polymer signal (1) 99

Figure 4-18. Determination of FT acrylate polymer signals (2) 100

IX List of tables

Table 2-1. Vessels used in the Mixed Liquor biodegradation experiment 27

Table 2-2. 8:2 FTOH Equivalents recovered from Hydrolysis Experimental Vessels 31

Table 2-3. Hydrolysis Study - percent of theoretical amount of 8:2 FTOH recovered 32

Table 2-4. 19F NMR analysis of FT acrylate polymer hydrolytic degradation 33

Table 2-5. Degradation Rates and Half Lives of FT polymer at various pH conditions 37

Table 2-6. 8:2 FTOH and Polymer Sorption to Sewage Organic Matter 45

Table 3-1. Soil Study: Controls and Experimental Vessels 59

Table 4-1. Polymer Quantification Calibration Curve Parameters 68

Table 4-2. Integration Values of 19F NMR calibration curve of polymer concentration 68

Table 4-3. Hydrolysis Experiment: Amount of 8:2 FTOH (ng) collected per time pomt 71

Table 4-4. Aggregate Amount of 8:2 FTOH (ng) collected by each time point 72

Table 4-5. Determination of FT-acrylate to hexadecyl acrylate Ratio of the Polymer 76

Table 4-6. Degradation trends of hydrolysis experimental vessels 89

Table 4-7. Hydrolytic Degradation Rates of the FT polymer at various pH conditions 89

Table 4-8. Viability Test - Evolution of PFHxA from 6:2 FTUCA 90

Table 4-9. Aggregate amount of 8:2 FTOH collected in control and experimental vessels 91

Table 4-10. PFHxA Evolution in Experimental Vessels overtime 92

Table 4-11. PFHpA Evolution in Experimental Vessels overtime 93

Table 4-12. PFOA Evolution (ng) in Experimental Vessels overtime 94

Table 4-13. 8:2 FTUCA Evolution (ng) in Experimental Vessels overtime 95

Table 4-14. 19F NMR Spectroscopy - Polymer Sorption to Sewage Sludge 96

x Chapter One:

Introduction to Perfluorinated Chemicals

1 1 Introduction to Perfluorinated Chemicals

1.1 Perfluorinated Carboxylic Acids

Fluorinated organic molecules are a unique class of compounds; for instance, the strong polarity and high bond-strength (approximately 484 kJ/mol) of the carbon-fluorine bond [1] imparts upon fluorinated organic compounds great chemical and thermal stability. Buttressed by other desirable characteristics such as hydro-/lipo-phobicity, organofluorine compounds are widely used in industry as surfactants, refrigerants, medicines, adhesives, and pesticides [1]. Perfluorinated chemicals are more sterically hindered, bulkier, stiffer and inflexible than hydrogenated carbon chained compounds [2] and possess the aforementioned chemical qualities. Because of these desirable characteristics, perfluorinated carboxylic acids (PFCAs), specifically perfluorooctanoic acid (PFOA), have been used as surfactants in the manufacturing of perfluorinated polymers, and their industrial application has spawned into a billion dollar industry over the past half century [1].

Perfluorinated compounds and their precursors are largely produced by two industrial synthetic methods: electrochemical fluorination (ECF) and telomerization [3]. The ECF method perfluorinates organic compounds of length "x" via electrolysis done in anhydrous hydrogen fluoride [4]. The resulting mixture includes the desired compound, CF^(CF2k-R, where "R" can be any functional group (COOH in the case of PFCAs), in its linear and branched isomeric forms. In the telomerization method, a "telogen" (perfluorinated ethyl iodide) is reacted with a "taxogen" (tetrafluoroethylene). The resulting product is then '"capped" with ethene, yielding a fluoroalkylethyl iodide (CFs^F^KCFUCFL-l), which can then be converted to other products such as fluorotelomer alcohols (CF3(CF2XCH2CFi2-OH), precursors to PFCAs. fluorinated polymers, and fluorinated surfactants.

Because of their chemical stability [1] and surface tension lowering properties [5], PFCAs have had and still have industrial application in consumer products. Despite these favourable applications, however, the use of PFCAs in the synthesis of perfluorinated polymers has been 2 under recent scientific scrutiny owing to the discovery of PFCAs' ubiquitous presence and persistence in the environment [6], accumulation in biological species [7], and potential toxicity [8]. Recent investigations into the toxicity of PFCAs in animals [9] have suggested that exposure to perfluoro-octanoic, nonanoic, and decanoic acids (PFOA, PFNA, and PFDA respectively) is correlated with delayed physical development [9], depressed ability to gain weight [10], peroxisome proliferation [11] which would indirectly lead to cancerous growths, and cardiac, circulatory, and hormonal complications [12]. Scientific endeavours are only beginning to discover and identify the potential consequences of the widespread usage of PFCAs and their precursors over the last 60 years, and their contamination of the environment.

1.2 Fluorotelomer Alcohols

Fluorotelomer alcohols are industrially synthesized via the telomerization process, as developed by the DuPont Company. In this process, a perfluoroethyl iodide (telogen) is photochemically transformed into a radical (CF3CF2) and radically reacted with tetrafluoroethene (taxogen) to the desired length. Ultimately, a compound with a general structure of CF'3(CF2)X-CH2CH2-Y, with '"x" representing an odd integer, and "Y'" representing an end group such as iodide. The resulting compound is then hydrolysed to yield the appropriate fluorotelomer alcohol (FTOH). FTOHs of different lengths are denoted by "A:2" where "A" represents the number of perfluorinated carbons in the FTOH molecule. For example, 8:2 FTOH contains eight perfluorinated carbon atoms and 2 hydrogenated carbon atoms. Compounds synthesized by telomerization can be synthesized according to a desired chemical structure; ECF, on the other hand, yields isomeric forms of the desired product in addition to the desired product.

In the early 1980s, Hagen et al. showed evidence of fluorotelomer alcohol degradation to the corresponding fluorotelomer carboxylic acid [13] and subsequent studies have led to the proposals of atmospheric degradation [14.15] and biodegradation [16] pathways of FTOHs to their corresponding PFCAs. The atmospheric and biodegradation transformations of FTOHs to their corresponding PFCAs (8:2 FTOH to PFOA for example) follow the pathways summarized in Figure 1-1 a and b respectively:

3 (a)

FFFFF FFF FFFFF FFF 8:2 FTOH 8:2FTAL

J OH

2 2NO

~i O

C8F17C(0)00- FFFFF FFF >^KA FFF FFFFF PFOA (C8 PFCA) C8 PFAL

C F 0- u/> 8 17

C8FJ7C(0)F CsFi7' (b)

F F F F F FFF 8:2 FTOH

FFFFF FFF 8:2 FTAL

-HF

F. F F, F F. F

FFF FFFFF 8:2 FTUAL

FFFFF FFF H FFFFF FFF ? A%V. beta-oxidation PFOA (C8 PFCA) 8:2 FTUCA

Figure 1-1. (a) atmospheric degradation pathway; (b) biodegradation pathway

4 Numerous studies investigating the biological transformation of FTOHs via metabolic and microbial processes have all shown that PFCAs of the corresponding length are inevitably yielded [16,17,18,19],

Fluorotelomer acrylate compounds are used in the synthesis of industrially and commercially used fluorinated polymers. As a part of her Ph.D thesis, J. Dinglasan-Panlilio (Mabury) demonstrated that 8:2 fluorotelomer acrylate and methacrylate degrade to 8:2 FTOH, which subsequently degrade to PFCAs and other intermediate metabolites, in a mixed-liquor wastewater microbial system [20]. The chemical structures of 8:2 FT acrylate and 8:2 FT methacrylate are shown in Figure l-2a and b respectively, (a) (b)

FFFFFFFF FFFFFFFF '

Figure 1-2. (a) 8:2 FT acrylate; (b) 8:2 FT methacrylate

In a recent study undertaken by Butt et al. [21], it was shown that biological transformation of 8:2 FT acrylate to fluorinated metabolites including 8:2 FTUCA, 8:2 FTCA, 7:3 FTCA, and PFOA occurred in Rainbow Trout. As fluorotelomer acrylate and fluorotelomer alcohols degrade to perfluorinated acids, it is of interest to determine if fluoro-acrylate based polymers also are subjected to similar degradation trends.

1.3 Fluorotelomer-based polymers

Fluorinated polymers bear many desirable characteristics including high thermal stability, excellent chemical resistance, and low surface energy [22]. Because of these desirable properties, fluoropolymers have found industrial and commercial applications as lubricants, elastomers, heat-transfer fluids, and surface protecting coatings [22,23]. Currently, major manufacturers of fluorinated polymers include Asahi Glass Fluoropolymers, Daikin, Dyneon, and DuPont Company [24], the latter of which synthesize telomer based fluorinated polymers. DuPont Company is also the only U.S. manufacturer of ammonium perfluorooctanoate - a

5 compound often used as an emulsifying agent in perfluorinated polymer (eg. polytetrafluoroethylene) synthesis [24].

Fluorotelomer alcohols are the precursors to fluorotelomer acrylates, which are used in the synthesis of fluorotelomer based polymers. These fluorotelomer-based polymers, in turn, are widely used in textile treatments [25], and upholstery and carpet industries as components of oil and water repelling coatings. Of the estimated 5000 tons (year 2000-2002 estimates) of FTOHs produced in the world annually, approximately 80% [26] is directed toward the synthesis of fluorotelomer based polymers. Many common industrially used fluorotelomer-based polymers are synthesized with fluorotelomer acrylate monomers [27] such as the 8:2 acrylate (2,2,3,3,4,4- 5,5,6.6.7,7.8,8,9,9-hexadecafluorononyl acrylate), which impart the oil and water repelling properties to the polymer, and non-fluorinated monomers such as hydrocarbon acrylates to improve the solubility of the polymer [28]. Polymer synthesis generally proceeds via radical polymerization [29]. A synthesis of a fluorotelomer based polymer is summarized in Figure 1-3:

w ci \\

Model Fluoiolelomer Potymer

Figure 1-3. Fluorotelomer-based polymer synthesis

A preliminary investigation into the lability of 8:2 fluorotelomer acrylate and methacrylate under bacterial conditions similar to those present in municipal waste water mixed liquor (a combination of raw sewage and a floe of microbial enzymes) has shown that these monomers

6 undergo degradation leading to PFCA precursor formation [20], and this formation is likely due to bacterial/microbial action [30]. Furthermore, it is probable that esterases would be active in the mixed liquor considering that these enzymes, in addition to proteases and lipases, are common additives to the mixed liquor bacterial floe [31]. As many different ester compounds have been shown to degrade in mixed liquor waste water samples, it is not surprising that fluorotelomer acrylate compounds, which contain ester linkages, would be susceptible to ester bond cleavage.

It has been surmised that about 60% of the total amount of fluorotelomer acrylate (whether incorporated polymeric or monomeric form) produced ultimately are emitted into the environment [32]. Of these emissions, approximately one-third is released into wastewaters while the remaining two-thirds are directed toward landfill sites. In turn, one of the fates of wastewater sludge (the organic material remaining at the end of the treatment process) is application to farmer's fields as fertilizer. With the high volume of FTOH production directed toward polymeric synthesis [26], much of the fluorotelomer chemicals released into the environment is found in polymeric forms such as polyethers. polyurethanes. and polyesters. Figure 1 -3 shows that the fluorinated and alkyl appendages are connected to the carbon chain backbone of the polymer by ester linkages. As these linkages are quite labile, it is foreseeable that degradation of the polymer would occur at these locations of the polymer leading to the release of FTOHs as degradation products. Degradation easily could be facilitated by bacterial/microbial and/or hydrolytic activities in an aqueous medium.

A 2002-2003 preliminary investigation completed by 3M Environmenlal Technology and Safety Services on the biodegradability of fluoroaliphatic polymers containing ester linkages in wastewater sewage sludge (project identification E02-0913) suggested that polymers containing fluoroaliphatic ester linkages have the potential to undergo degradation in microbially rich wastewaters [33]. In this study however, degradation was assessed on measuring the evolution of suspected degradation products rather than measuring the loss of the polymeric material. In 2008, Russell et al. published the first widely recognized peer-reviewed article on the biodegradation potential of fluoroacrylate polymer products in soils [34|. In this study, the degradation of a test substance - a complex mixture of fluoro acrylate polymers, residual 7 materials, hydrocarbon surfactants, and water - in soils was evaluated. The study attempted to capture the evolution of both suspected volatile and involatile polymer degradation products in the experimental vessels. It was ultimately concluded at the end of this study that fluorotelomer acrylate polymers have half-lives of 1000-2000 years in soil environments, suggesting that fluorotelomer acrylate polymers do not rapidly degrade in the environment. However, there were numerous potential sources of errors with this experiment. Firstly, residual materials were not removed from the test substance. This is problematic considering that these residual materials include compounds that have been shown to degrade into products that are the same compounds as those being monitored in the experiment. Therefore, it would have been difficult for the investigators to differentiate degradation coming residual products, and degradation originating from the tested fluoroacrylate polymer. In addition, experimental conditions did not simulate natural conditions as experimental soils were devoid of vegetation growth. Soil microbes exist symbiotically with plants and an absence of plants decreases soil microbial activity. Thirdly, the viability of the microbes in the soil was not tested, and as a result, it would have been difficult to determine if microbes were even active during the experiment. Lastly, the concentration of the investigated polymer over the course of the experiment was not determined. Such experimental difficulties would naturally call into question the validity of the obtained results, and the continuing uncertainty of the potential contribution from fluorotelomer polymers to the PFCA burden on the environment thus laid the research foundations outlined in the current thesis.

1.4 Research Objectives

The purpose of the research documented in the current thesis was to assess the degradation potential of fluorotelomer acrylate based polymers in surface waters and sewage wastewaters. Specifically, the lability of the ester linkages between the fluorinated appendages, which upon breakage would yield fluorotelomer alcohols and subsequently perfluorinated acids, and the polymeric carbon chain backbone was investigated. The research was divided into two studies: a hydrolysis study and a wastewater biodegradation study. The research hoped to provide further insight on the fate of fluorotelomer acrylate polymers in environmentally relevant waterways. Unlike previous experiments which replied solely on monitoring for suspected

8 degradation products to determine the extent of degradation of a target compound, the current thesis, in addition to monitoring for the evolution of suspected degradation products of the FT acrylate polymer, monitored for the loss of the fluorotelomer acrylate based polymer over the duration of the experiment.

9 1.5 Literature Cited

I] Key BD, Howell RD, Criddle CS. 1997. Fluroinated organics in the biosphere. Environ. Sci. Technol. 31: 2445-2454.

2] Simons JH, Francis HT. Hogg JA. 1949. Journ. Electrochem. Soc. 95: 53-55

3] Kissa. E. 2001. Fluorinated surfactants and repellants. Marcel Dekker, New York, USA.

4] Conte L. Gambaretto G. 2004. Electrochemical fluorination: state of the art and future tendencies. /. Fluorine Chem., 125: 139-144.

5] Szajdzinska-Pietek E. Schlick S. Plonka A. 1994. Self-assembling of perfluorinated polymeric surfactants in water. Electron-spin resonance spectra of nitroxide spin probes in Nation solutions and swollen membranes. Langmuir. 10: 1101-1109.

'6] Giesy JP, Kannan K. 2002. Perfluorochemical surfactants in the environment. Environ. Sci. Technol. 36: 146A-152A

7] Martin J, Whittle DM, Muir DCG. Mabury SA. 2004. Perfluoroalkyl contaminants in a food web from lake Ontario. Environ. Sci. Technol. 38: 5379-5385.

8] Lau C, Anitole K, Hodes C, Lai D, Pfahles-Hutchens A, Seed J. 2007. Perfluoroalkyl acids: a review of monitoring and toxicological findings. Tox. Sci. 99: 366-394.

9] Lau C, Butenhoff JL, Rogers JM. 2004. The developmental toxicity of perfluoroalkyl acids and their derivatives. ToxApp. Pharmacol. 198: 231-241.

40] Butenhoff JL, Kennedy GL, Frame SR, O'Connor JC, York RG. 2004. The reproductive toxicology of ammonium perfluorooctanoate (APFO) in the rat. Toxicology. 196: 95-116.

II] Ikeda T Aiba K. Fukuda K, Tanaka M. 1985. The induction of peroxisome proliferation in rat-liver by perfluorinated fatty-acids, metabolically inert derivatives of fatty-acids. /. Biochem. 98: 475-482.

12] Langley AE, Pilcher GD. 1985. Thyroid, bradycardic and hypothermic effects of perfluoro-n-decanoic acid in rats../. Toxicol. Environ. Health. 15: 485-491.

13] Hagen DF. Belisle J, Johnson JD. Venkateswarlu P. 1981. Characterization of fluorinated metabolites by a gas chromatographic-helium microwave plasma detector - the biotransformation of 1H, 1H. 2H. 2H-perfluorodecanol to perfluorooctanoate. Anal. Biochem. 118: 336-343.

10 [14] Ellis DA, Martin JW, de Silva AO. Mabury SA, Hurley MD, Andersen MPS, Wallington TJ. 2004. Degradation of fluorotelomer alcohols: A likely atmospheric source of perfluorinated carboxylic acids. Environ. Sci. Technol. 38: 3316-3321.

[15] Hurley MD, Ball JC, Wallington TJ. Andersen MPS, Ellis DA. Martin JW, Mabury SA. 2004. Atmospheric chemistry of 4:2 fluorotelomer alcohol (CF3(CF2)(3)CH2CH20H): Products and mechanism of CI atom initiated oxidation. /. Phys.Chem. A. 108: 5635-5642.

[16] Dinglasan MJA, Ye Y, Edwards EA. Mabury SA. 2004. Fluorotelomer alcohol biodegradation yields poly- and perfluorinated acids. Environ. Sci. Technol. 38: 2857- 2864.

[17] Wang N. Szotek B, Folsom PW. Sulecki LM. Capka V, Buck RC, Berti WR, Gannon JT. 2005. Aerobic biotransformation of 14C-labeled 8-2 telomer B alcohol by activated sludge from a domestic sewage treatment plant. Environ. Sci. Technol. 39: 531-538.

[18] Wang N, Szotek B, Buck RC. Folsom PW. Sulecki LM, Capka V, Berti WR. Gannon JT. 2005. Fluorotelomer alcohol biodegradation-direct evidence that perfluorinated carbon chains breakdown. Environ. Sci. Technol. 39: 7516-7528.

[19] Martin JW, Mabury SA. O'Brien PJ. 2005. Metabolic products and pathways of fluorotelomer alcohols in isolated rat hepatocytes. Chem. Biol. Interact. 155: 165-180.

[20] Dinglasan-Panlilio, M.J.A. PhD Thesis. University of Toronto, 2007.

[21] Butt CM. Mabury SA, Muir DCG. 2008. Bioaccumulation and biotrnsformation of 8:2 FTOH acrylate in Rainbow Trout. Research Triangle Park, NC, USA. June 3-4. 2008. (poster)

[22] Hung MH, Farnham WB, Feiring AE, Rozen S. Chapter 4: Functional fluoromonomers and fluoropolymers. In Fluoropolymers 1: Synthesis. Hougham G, Cassidy PE. Johns K, Davidson T, Eds.: Plenum Press: New York, 1999. pp. 51-67.

[23] Rao NS, Baker BE. Textile finishes & fluorosurfactants. Organofluorine Chemistry. Principles and Commercial Applications. Banks RE. Smart BE, Tatlow JC, Eds.; Plenum Press: New York, 1994. pp. 321-326.

[24] EPA. Fluoropolymers in the Environment. U.S. EPA Administrative Record. EPA-HQ- OPPT-2003-0012-0267: 2003.

[25] Dinglasan MJA. Ye Y, Edwards EA. Mabury SA. 2004. Fluorotelomer alcohol biodegradation yields poly- and perfluorinated acids. Environ. Sci. Tec hnol. 38: 2857- 2864.

11 [26] DuPont DuPont Global PFOA Strategy - Comprehensic Source Reduction, U.S. Environmental Protection Agency.

[27] Castelvetro V. Aglietto M, Ciardelli F. Chiantorre O. Lazzari M. 2002. Structure control, coating properties, and durability of fluorinated acrylic-based polymers. /. Coatings Technol. 74: 57-66.

[28] Imae T. 2003. Fluorinated polymers. Curr. Opin. Colloid interface Sci. 8: 307-314.

[29] Saidi S, Guittard F, Guimon C, Geribaldi S. 2006. Fluorinated acrylic polymers: surface properties and XPS investigations. /. Appl. Pol. Sci. 99: 821-827.

[30] Krupka RM. 1967. Evidence for an intermediate in acetylation reaction of acetylcholinesterase. Biochem. 6: 1183-1190.

[31] Boczar BA. Forney LJ, Begley WM, Larson RJ, Federle TW. 2001. Characterization and distribution of esterase activity in activated sludge. Wat. Res. 35: 4208-4216.

[32] Van Zelm R. Huijbregts MAJ. Russell MH, Jager T, van de Meent D. 2008. Modeling the environmental fate of perfluorooctanoate and its precursors from global fluorotelomer acrylate polymer use. Env. Tox. Chem. 27: 2216-2223.

[33] 3M Environmental Technology and Safety Services. Inherent Aerobic Aquatic Biodegradability of Fluoroaliphatic Polymeric Ester of [ ]. Project Identification E02- 0913. 2003.

[34] Russell MH, Berti WR, Szostek B, Buck RC. 2008. Investigation of the biodegradation potential of fluoroacrylate polymer product in aerobic soils. Environ. Sci. Technol. 42: 800-807.

12 Chapter Two:

Degradation of Fluorotelomer-based Polymers in Sewage Wastewaters

13 2 Degradation of Fluorotelomer based Polymers in Wastewaters

The results presented in the current thesis chapter are intended for future publication.

2.1 Abstract

The presented studies explored the susceptibility of a residual-free solubilized fluorotelomer (FT) acrylate polymer to hydrolysis, and microbe mediated degradation in wastewater mixed liquor. In the hydrolysis study, evolution of 8:2 FTOH from polymer hydrolysis followed a logarithmic trend, suggesting pseudo-first order degradation kinetics of the polymer. Fluorotelomer-acrylate polymer "'half-lives" at pHs 6. 8, and 10 were calculated to be 90±10 days, 80±10 days, and 10.0±0.6 days respectively. Evidence of hydrolytic degradation of the fluorotelomer acrylate polymer was further supported by spectral data gained from 19F NMR spectroscopy and MALDI-ToF analyses, both of which suggest FT polymer degradation potential at environmentally relevant conditions, and near complete to complete FT polymer degradation at pH 10 conditions. In the wastewater mediated study, the formation of 8:2 FTOH greater than what can be attributed to hydrolysis was observed in the test vessels as compared to control vessels. In addition, significant formation of PFHxA. PFHpA, PFOA, and 8:2 FTUCA was observed in the test vessels. No such trends were observed in the control vessels. Production of PFHxA, PFHpA, PFOA peaked at 12±2. 10±2, and 11 ±2 days; the greatest concentration of 8:2 FTUCA in the test vessels were observed at approximately 5.5 days. The findings of the two conducted studies suggest that FT acrylate polymer degradation proceeds hydrolytically and microbially. It is suggested from the results that the degradation of fluorinated polymers contributes potentially to the perfluorocarboxylate (PFCA) burden on the environment.

14 2.2 Introduction

The ubiquitous presence of perfluorocarboxylates [F(CF2)nCOO", PFCAs] in environmental waters [1,2] and sediment [3], arctic biota [4], and humans [5] has caused scientific concern considering that PFCAs consisting of seven or greater number of carbons in their backbone have been shown also to be bio accumulative and potentially toxic [6]. It has been suggested that the direct release of PFCAs from industrial applications is a significant contributor of historical PFCA emissions [7]. As direct sources of PFCA emission already have been shown to contribute to environmental PFCA concentrations, scientific research is now focusing on the potential contribution of indirect sources to the environmental PFCA burden.

Fluorotelomer alcohols (FTOHs) are linear fluorinated alcohols that are employed as manufacturing intermediates for a variety of consumer and industrial products [8]. It has been shown that FTOHs undergo atmospheric [9,10], metabolic [11.12] and microbial [13] degradation pathways that ultimately lead to the production of PFCAs and other analytes. FTOHs are produced globally at an estimated rate of 5000 to 6500 tons per year (between 2000 and 2002), of which an estimated 80% is directed toward polymer synthetic applications [14]. Ruorotelomer acrylates, which are used to synthesize FT-based acrylate polymers [15]. are themselves synthesized from fluorotelomer alcohols. With wide industrial applications in textile, upholstery, carpet, apparel and leather industries as components of surface protecting coatings [16], it is appropriate therefore to investigate the potential environmental fate of FT-based acrylate polymers. Currently, only two published studies have been dedicated to studying the potential fate of fluorinated polymers [15,17]. and this may reflect a long-standing, but scientifically unsubstantiated, presumption that fluorotelomer acrylate polymers, owing to their size and bulk, would not readily undergo degradation.

One of the main hurdles in investigating the environmental fate of polymers is differentiating between potential polymer degradative products and residual compounds of the polymer. Residual compounds can be viewed as unreacted synthesis reagents or impurities that remain

15 associated either on or in the intended product. For example, residual compounds for an FT- based acrylate polymer include FT-acrylate, FTOHs. PFCAs. and other fluorinated species [15] and have been shown to account for up to 4% (on the basis of mass per dry mass of initial material) of the total synthesized product [18]. Without proper removal of residual compounds, the polymer degradation cannot be effectively monitored. In the first widely recognized peer- reviewed article that addressed FT-based acrylate polymer degradation in the environment, Russell et al. studied the fate of fluoro acrylate polymers in soils and suggested that the biodegradation half-life of these polymers was between 1200-1700 years [15]. There are, however, improvements that should have been made to this initial study. Firstly, fluorotelomer residual compounds were not removed from the experimental system. As fluoro acrylate polymers potentially degrade to the same compounds as the residual compounds, it would have been difficult for the investigators to distinguish between the production of degradation compounds as a result of polymer degradation versus the degradation of residual compounds. Secondly, the soil environment used in the experiment was devoid of vegetation growth and as a result was not representative of conditions found in nature. Thirdly, as Ihe viability of the microbes in the soil was not tested, it would not have been possible to ascertain the activity of the soil microbes during the experiment. Also, the polymer concentration was not monitored. A modelling study complementary to the aforementioned research, however, supports the notion that fluorotelomer based acrylate polymers are longdived in the environment [17].

Because of the continued uncertainty surrounding the potential contribution of FT-based polymer degradation to the environmental PFCA burden, the degradation potential of a residual-free solubilized FT-based acrylate polymer in two water systems was investigated. The studied FT- based polymer was in-house synthesized and modeled the fluorinated polymers potentially used commercially. The first study investigated the susceptibility of the polymer to hydrolysis at various pH levels. The second study investigated the degradation potential of the polymer in an undiluted wastewater mixed liquor medium. Fluorochemicals have been previously observed in wastewater treatment plants [19] and it has been shown that fluorinated chemicals enter these systems through industrial and consumer waste disposal procedures. In the current studies, the

16 lability of the ester linkages in the model FT-based acrylate polymer under environmentally relevant conditions was investigated. The investigation of the degradation potential of the synthesized polymer described in the current thesis was a model for the fate of FT-based acrylate polymers in the environment.

2.3 Experimental Section

2.3.1 Chemicals

2(pertluorooctyl)ethyl acrylate (8:2 FTOH acrylate, 97%) and hexadecyl acrylate (97%) were acquired from Oakwood Research Chemicals (West Columbia, SC) and Monomer-Polymer & Dajac Laboratories (Feasterville, PA) respectively and used in polymer synthesis. 8:2 fluorotelomer alcohol (8:2 FTOH, 97%) and perfluorohexanoic acid (PFHxA, 95%) standards were acquired from Oakwood Research Chemicals. Perfluoroheptanoic acid (PFHpA, 99%) perfluorooctanoic acid (PFOA, 96%), perfluorononanoic acid (PFNA, 97%), perfluorodecanoic acid (PFDA, 98%), perfluoroundecanoic acid (PFUDA, 95%), and mercuric chloride were purchased from Aldrich Chemical Co. (Milwaukee, WI). The saturated telomer acid (8:2 FTCA) and the unsaturated telomer acids (6:2 and 8:2 FTUCA) were prepared according to Achilefu et al (20) to a purity of >95%. Sodium perfluoro-1-octane sulfonate (PFOS) and the stable isotope 13 13 13 13 standards of C4-PFOA, C5-PFNA, C4-PFOS, 8:2 C2-FTUCA were provided by Wellington Laboratories (Guelph, ON). 2H,2H,3H,3H-perfluorodecanoic acid (7:3 telomer acid, 97%) was acquired from Synquest Co. (Alachua, Fl).

2.3.2 Polymer Synthesis

The co-polymerization of 8:2 FTOH acrylate and hexadecyl acrylate in equal molar ratios was performed in ethyl acetate; a,a-azobis-isobutyronitrile (A1BN) was employed as the radical initiator. The solvent and monomer reagents were mixed in a 90:10 (w/w) ratio. The synthesis was performed in a nitrogenous environment in a three-necked round bottom flask equipped with a condenser. AIBN was used in the reactions at 0.1% (w/w) and the polymerization reaction proceeded for 19 hours. The temperature was maintained at 70°C throughout the duration of the

17 reaction. The product was then precipitated in methanol, vacuum filtered and finally air-dried in the fumehood. Unreacted reagents were removed initially from the product through a series of washes using a 75:25 methanol: water solution. The total recovery was between 70 to 80%.

+ AIBN

hexadecyl acrylate 8:2 FT acrylate

Figure 2-1. Fluorotelomer-based acrylate polymer synthesis

2.3.3 Polymer Characterization

The synthesis of the fluorinated polymer was confirmed using iyTF and H NMR spectroscopy on a Varian 400MHz system with an ATB8123-400 auto switchable probe. Deuterated chloroform was utilized as the solvent with tetramethylsilane (TMS) as the internal standard for *H NMR spectroscopy. 4-trifluoromethoxyacetanilide, which has a chemical shift of -58 ppm, was used as the internal standard for 19F NMR spectroscopy. 0.0 ppm is defined as the 19F NMR chemical shift of CFCI3. A schematic of the fluorotelomer acrylate based polymer and a 19F NMR spectrum are provided in Figure 2-2.

18 (a) (b)

5 4

6 5

o= o 1 I I i i r~i 1 i i i i | i i i i [ r~ —|—\—i—'—i—(—r r-p-r -BO -tO -It -80 -WO -110 -130 PP"

Figure 2-2. (a) Schematic of Model Polymer (b) 19F NMR spectrum of polymer

For identification purposes, fluorine atoms corresponding to their positions on the fluorotelomer appendage have been replaced with numbers in Figure 2-2a, and the corresponding signals have been identified on the 19F NMR spectrum shown in Figure 2-2b. Similar 19F NMR characterizations have been performed previously on related perfluorinated compounds [21, 22, 23]. For reference, the broad signals attributed to the synthesized polymer in Figure 2-2b (signals 1, 6, 5, 4, 3, and 2) were compared to the narrow signal (-58 ppm) of the internal standard compound, 4-trifluoromethoxyacetanilide. Additional ]H NMR characterization on this synthesized polymer has been described previously in Joyce Dinglasan-Panlilio's Ph.D thesis [24]. The 'H NMR spectra of the 8:2 fluorotelomer acrylate and hexadecyl acrylate monomers used in the polymer synthesis process showed the presence of vinylic hydrogen atoms in the monomers. However, the ' H NMR spectrum of the synthesized polymer showed no evidence of vinylic hydrogen atoms, suggesting that the expected radical polymerization process had occurred during polymer synthesis. 'H NMR spectra supporting this observation can be found in the fifth chapter of Joyce Dinglasan's Ph.D thesis [24].

19 Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) was used to gain information on the chemical structure of the synthesized polymer. The polymer was characterized in the linear and positive ion modes of a Waters Micromass MALDI micro MX1M time-of-flight mass spectrometer. At the time of sample analysis, the backing/inlet and analysis pressures were set at 10" mbar and 10" mbar respectively; the flight tube voltage was set at 12,000V; a 337 nm laser was used for data acquisition and fired at a frequency of 5Hz. 10 scans at a scanning rate of 0.6 seconds per scan comprise a spectrum, and a minimum of 40 spectra were acquired. Mass to charge ratios of less than 1000 were suppressed during analyses. In preparation for MALDI analysis, sample wells were initially coated with a thin layer of graphite deposited onto the wells through a graphite/chloroform mixture. The aqueous mixture was prepared by vigorously vortexing the mixture for one hour. The mixture was then applied to the sample wells and allowed to air-dry. leaving behind a thin coating of graphite. A solution of lOmg/mL of Dithranol and 1 mg/lmL of lithium trifluoroacetate was then applied to the graphite coated sample well. The actual fluorotelomer acrylate based polymer sample was then applied to the sample well, and the sample was allowed to dry thoroughly prior to analysis.

The MALDI spectrum of the fluorotelomer acrylate based polymer used in this study is presented in Figure 2-3.

20 ^/.tui'. MilMw^Mvytiv^toMw s ^ * or-o 1500 WMMA j' "o i VAC or co a> a trhio ^o x>c *& sn J&J 9G9J s^ioc Figure 2-3. MALDI Spectrum of synthesized fluorotelomer acrylate based polymer

The weight average molar weight (Mw) of the polymer was calculated according to the following equation:

Mw = XAW (1) where M represents the masses of the polymer and N represents the intensity of the monitored m/z signals. The number average molar weight (Mn) was determined as follows:

Mn = SLY, 1 (2)

It was suggested from MALDI analysis that the synthesized polymer had an Mw and Mn of 4570 and 3430 respectively, and a polydispersity index of 1 33

Gel permeation chromatography (GPC) was used to determine the average molecular weight

(Mn) and size average (Mw) of the polymei Samples for GPC analysis were prepared in

21 tetrahydrofuran (THF) and analyzed using a Viscotek Model 100 system equipped with a refractive index detector (calibrated with polystyrene standards) and a phenogel linear X3 column at a 1.0 mL/min flow rate. The Mn and Mw determined by GPC analysis of the synthesized polymer were 11.100 amu and 25.900 amu respectively. The polydispersity index (PDI) of the synthesized polymer was 2.33. However, GPC is prone to solvent effects, such as polymer micellation or dimerization, that would lead to an artificial increase of measured molecular weight values.

2.3.4 Polymer Solubility and Residual Removal

40 mg of the in-house synthesized fluorotelomer acrylate based polymer was added to 200 mL of Barnstead E-pure water with a resistivity of 18 MQcm"1 that had been buffered to pH = 4 using acetic acid and sodium acetate. Dodecylamine hydrochloride and sodium salicylate acted as the surfactant and hydrotrope respectively. A hydrotrope/surfactant solution was selected owing to their ability to solubilize high molecular weight organic compounds [25]. The polymer:surfactant, polymer:hydrotrope w/w ratios were 1:10 and 1:6 respectively. The polymer was allowed to solubilize at 308 K over 24 hours, and the solution was then continuously purged with Supelco Supelpure1M HC carbon trap filtered air for a 30 day period prior to the start of the present studies. Owing to the volatility of both the 8:2 FTOH acrylate and 8:2 FTOH, residual compounds that were present in the solubilized solution were removed effectively during the 30 day period. Other residual compounds [15] typically found in industrial fluorotelomer acrylate based polymer syntheses were not monitored for in the described studies; these compounds were never used in the synthetic process described in section 2.3.2, and therefore were not expected to be present as residuals in the currently described model polymer.

After 30 days, a 5 mL aliquot of the prepared solution was spiked into a glass vessel (see Figure 2-5) with 200 mL of I8MQCI1T1 water each and aerated continuously for 2 days. Volatile compounds were collected on XAD cartridges. The prepared solution was deemed ''residual- free" if the aliquot measurements yielded no levels beyond those of background levels of 8:2 acrylate or 8:2 FTOH in the subsequent GC-MS analysis. A GC chromatogiam of the polymer

22 solution after the residual removal process is provided in Figure 2-4. No 8:2 FTOH acrylate and low 8:2 FTOH amounts native to the polymer solution (0.036% by weight) were detected.

38C

34Q VTA^VAJ. \W-1KJ^M*AVT^A^'

300

26C 8:2 FT acrvlate

22C 8:2 FTOH 1

14C

IOC

4.00 5.00 6.00 7.00 8.00 i.OO 10.00 11.00 12.00

Figure 2-4. GC chromatogram of polymer solution after 30 days of residual purging, immediately prior to the start of the experiment

The amount of polymer dissolved in solution was determined by performing 19F NMR spectroscopy on a Varian 400 MHz system with an ATB8123-400 auto switchable probe. A linear calibration curve was created by comparing the intensity of the trifluoromethoxyacetanilide signal (-58 ppm) against the -CF3 groups (-81 ppm) of the fluorinated appendages of the polymer. A KJmL aliquot of the solubilized polymer solution was removed and evaporated to dryness in the fume-hood. The dried aliquot was then reconstituted in 5mL of deuterated chloroform (d-chloroform), and the d-chloroform fraction was then back extracted three times with three 5 mL pH = 12 water fractions to remove acetic acid and sodium salicylate that may have been present in the d-chloroform. The d-chloroform fraction was finally concentrated to 0.5 mL.

The polymer remained within the d-chloroform fraction during the back-extraction procedure as subsequent 19F NMR analyses of the back-extraction water fractions showed no fluorine signals

23 beyond background. NMR samples consisting of 0.46 mL of the prepared d-chloroform fraction, 0.3 mL of deuterated chloroform, and 0.04 mL of 800ppm chloroform solution of 4- trifluoromethoxyacetanilide, were prepared. 19FNMR samples were run at 298 K. The relaxation delay was set at 10 seconds, and an average of 560 scans was performed per sample. Through these analyses, it was determined that the prepared polymer solution actually had a dissolved polymer concentration of 54±3 ppm. A further description of the quantification of the polymer concentration in solution is provided in the appendix in section 4.1.

Polymer solubility was integral to investigating the degradation of the synthesized polymer. Solubilizing the polymer in this experiment served two functions. Firstly, it allowed any volatile residuals trapped within the polymer matrix to be released prior to the start of the studies. The removal of residuals from the polymer system was necessary to avoid potential residual degradation from interfering with the analysis of potential polymer degradation. The prepared polymer solution used in the studies was deemed "residual-free" and as a result, any observed degradation in the studies documented in this thesis would have originated solely from the degradation of the solubilized polymer under the stated experimental conditions. Secondly, solubilizing the polymer would mimic polymer solutions available to consumers and industrial purposes [26,27] as many of these polymers are applied in solution form lo fabric as part of protective coatings.

2.3.5 Experimental Set-up

Two studies were completed in the investigation of the degradation potential of fluorotelomer acrylate based polymers in the environment: a hydrolysis study, and a wastewater study.

Hydrolysis Study: A modification of the purge and trap experimental design, as described in Dinglasan-Panlilio et al. [18], was used in this experiment. The aqueous medium accounted for 200mL of the vessel volume with 75 mL of volume allotted for headspace. A 1 OmL aliquot of the 54±3 ppm polymer solution was added to 190 mL of the aqueous medium. As a result, the starting concentration of polymer per experimental vessel was 2.7±0.2 ppm. Bottle caps were

24 modified to accommodate Orbo Amberlite XAD-2 cartridges (lOOmg). Vessels were tightly sealed and carbon filtered in-house air was continuously introduced into the vessels throughout the experiments with the XAD cartridge being the only channel of air removal from the vessels. The fate of the solubilized fluorotelomer acrylate based polymer at 295.5K and four pH treatments - 4.00±0.01, 6.00±0.01, 8.00±0.01, and 10.00±0.01 - was investigated in the hydrolysis study. Barnstead E-pure water with a resistivity of ISMQcm"1 was used as the aqueous medium. XAD cartridges were periodically sampled for the volatile compounds of 8:2 FTOH acrylate and 8:2 FTOH. All pH conditions were tested in triplicate. The hydrolysis experiment proceeded for 80 days.

XAD • I Air Line

Experimental V essel

Figure 2-5. Schematic Diagram of Experimental Set-up for Hydrolysis/Wastewater Studies

Results from the hydrolysis experiment were also gathered by 19F NMR spectroscopy and MALDI-MS analyses. For these two analyses, experimental vessels, at the end of the 80 day study, were concentrated to 10 mL in volume. These concentrated experimental samples were then extracted with three lOmL fractions of chloroform. The chloroform fractions were then concentrated to 5 mL and back extracted with pH 12 water fractions. The chloroform was then passed through a silica gel column, and concentrated to the desired volume. For 19F NMR spectroscopy analysis, the collected chloroform fraction was concentrated to 0.5mL. From the 0.5 mL fraction, a 0.46 mL aliquot was removed and added to 0.3 mL of deuterated chloroform, and 0.04 mL of an 800 ppm chloroform solution of 4-trifluoromethoxyacetanilide to comprise the 19F NMR sample. 19F NMR samples were run at 298 K. The relaxation delay was set at 10

25 seconds, and an average of 560 scans was performed per sample. Experimental samples intended for MALDI-MS analyses were concentrated to 250 uL, and analysed according to the procedure outlined in section 2.3.3.

Wastewater Study: Mixed liquor is a product of one of the primary processes in treating industrial wastewater (raw sewage) where a microbial floe is combined with the raw sewage to reduce the organic content in the sewage. In the wastewater mediated study, undiluted mixed liquor was collected in one litre polypropylene bottles from the Ashbridges Bay Wastewater Treatment Facility in Toronto, Ontario and transferred into the experimental glass vessels at the collection site. Samples were stored on ice during transport to the laboratory.

Similar to the hydrolysis study, the aqueous medium accounted for 200 mL of the vessel volume with 75mL of volume allotted for headspace. 10 mL aliquots of the 54±3 ppm polymer solution were added to 190 mL of the sewage sludge media, resulting in a starting polymer concentration per experimental vessel of 2.7±0.2 ppm. Six vessels that were to serve as controls were autoclaved at 394 K for 30 minutes (liq30 cycle) using a Steris SG-120 Scientific Gravity Sterilizer. The remaining vessels were immediately put under aeration. 0.2 mL of a 0.125 ppm solution of mercuric chloride (biocide) was added weekly into the autoclaved vessels. These autoclaved vessels with biocide were then placed under aeration as well. Vessels were purged for two days prior to the start of this study to remove any potential volatile target analytes native to the mixed liquor. During this study, vessels were shaken on a Lab-line 4626 bench-top shaker set at 130 r.p.m. to ensure even mixing of aqueous and solid suspensions in the vessels. Control and experimental vessels used in this study were prepared in at least triplicate and are described in Table 2-1. pH measurements were taken at the beginning and end of the experiment for all vessels. A pH level of 6.0±0.1 (SD) was recorded for all vessels at the time of measurement. The wastewater sewage experiment proceeded for 156 days.

26 Vessels: Number of Replicates:

Control Vessels:

1. NON-ACTIVE mixed liquor and biocide WITHOUT polymer three

2. NON-ACTIVE mixed liquor and biocide WITH polymer three

3. ACTIVE mixed liquor WITHOUT polymer three

4. ACTIVE mixed liquor WITH surfactant only three

5. ACTIVE mixed liquor spiked with 4ppb 8:2 FTOH. three

Test Vessels:

ACTIVE mixed liquor WITH polymer four

Table 2-1. Vessels used in the Mixed Liquor biodegradation experiment

2.3.6 Vessel Headspace Analysis

XAD cartridge contents were extracted with 2 mL of ethyl acetate Iwice. Extracts were recombined before being transferred into GC sampling vials. The breakthrough compartment of the XAD cartridge was extracted separately from the main XAD compartment. Samples were analyzed using a Hewlett-Packard 6890 gas chromatograph equipped with a 5793 inter mass spectrometer detector. The separation of the target analytes 8:2 FTOH acrylate and 8:2 FTOH was achieved using a 30m Zebron1M ZB-WAX column (0.25mm i.d., 0.25um film thickness). The temperature of the GC oven was initially held at 60°C from 0-1 minutes, then ramped at a 5°C/min rate from 60-75°C, 10°C/min from 75-130°C, and finally 50°C/min from 130-240°C. The total run time was 12.7 minutes. Helium was used as the carrier gas at a flow rate of lmL/min with pulsed splitless injection at an initial pressure of 20psi at 220°C. Analytes were identified under positive chemical ionization (PCI) mode in single ion monitoring mode, and the molecular ion (M+l) was monitored for 8:2 FTOH acrylate and 8:2 FTOH in both the hydrolysis and wastewater mediated studies. External calibration curves between 10 and 300 pg/uL for both analytes were used to quantify the concentrations of analytes. Linearity (r~ > 0.99) was observed

27 for the calibration curves. The limit of quantitation was defined as the lowest standard to yield a signal to noise ratio of >10 which corresponded to the lOpg/uL standard for both the 8:2 FT acrylate and 8:2 FTOH analytes.

2.3.7 Vessel Aqueous Medium Analysis

Quantitative analysis of aqueous media was performed on the Waters Acquity ultra performance liquid chromatography system (UPLC"') coupled to a Quattro microm high performance triple quadrapole mass-spectrometer (LC-MS/MS) in negative electrospray mode. Injection volumes were 25uL and the flow rate was 360uJL/min. Chromatography was done on a Phenomenex Luna 2.5um C18(2)-HST column (50 mm in length, 2 mm i.d., 2.5 um particle size) preceded by a CI8 guard column (4.0 by 2.0 mm. Phenomenex, Torrance, CA). The mobile phase was a lOmM ammonium acetate buffered methanol/water mixture and the analytes were separated using gradient conditions. An initial 60:40 methanol:water mixture was increased to 80:20 methanokwater over 6 minutes followed by a 2 minute hold, before reverting to initial conditions. Compounds analyzed for in the aqueous media included perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA). perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnA), 7:3 and 8:2 FTCA, 8:2 FTUCA, and perfluorooctane sulfonate (PFOS).

Analyte concentrations in samples were determined by internal calibration. The final

1 % concentration of each internal standard in each sample was 12.5 ng/mL. Q-PFOA was used for 13 13 PFHxA, PFHpA, and PFOA, C5-PFNA was used for PFNA, PFDA, and PFUnA, 8:2 C2- 13 FTUCA was used for 6:2 and 8:2 FTUCA as well as 7:3 and 8:2 FTCA, and C4-PFOS was used for PFOS. All internally labelled standards were donated by Wellington Laboratories (Guelph, ON). Samples were extracted and prepared for LC analysis using the ion-pairing method described by Hansen et al. [5]. Since the Hansen method was introduced in 2001, other methods of PFCA extraction from environmental matrices have been developed. One method that has garnered attention for its extraction efficiency is a method presented by Higgins et al. [3]. A comparison between the PFCA extraction methods of Hansen et al. [5] and Higgins et al.

28 [3], and a justification for the use of the Hansen method in this study are provided in section 4.2 located in the appendix of the current thesis.

2.3.8 Data Analysis

PFHxA, PFHpA, and PFOA formations shown in Figure 2-10 were modeled by a 2D sigmoidal with an offset equation:

y = a/(1.0 + e(-(x"bVc)) + d (3) where a is a scaling factor, b is the position of maximum change, c is the spread of data (time in this study) around b, d is an offset value (analyte background level in this study), y is amount of analyte in nanograms, and x is time. The purpose of sigmoidal modeling is to determine the time of peak analyte formation as denoted by variable b in the equation. 8:2 FTUCA peak concentration shown in Figure 2-lOd was modeled by a 2D cubic function:

y = a + bx + ex2 + dx3 (4)

The results were modeled according to the fit of the data relative to parabolic curve of the cubic function. The derivative of this resulting equation was taken and the change in response over time (dy/dx) was set to zero to determine the time of peak concentration.

2.3.9 Quality Assurance and Control

QA/QC data included instrumental blanks, procedural blanks, and at least triplicate analyses of sample sets. Recoveries from three trials of the targeted PFCAs were 80% and above. 8:2 FTOH was spiked into an aerated aqueous medium of 18 MQcm"1 water. The recovered percentage of 8:2 FTOH through headspace analysis after three days was 88±3% via external calibration (EC) analysis. The viability of the wastewater mixed liquor medium was monitored by adding 6:2 FTUCA to a set of control bottles that contained only undiluted, aerated mixed liquor, and monitoring for the evolution of PFHxA. The viability test is discussed further in section 2.4.2.

29 2.4 Results and Discussion

Compounds that are either directly or indirectly used in the synthesis of FT-based acrylate polymers such as the fluorotelomer alcohols, as well as the fluorotelomer acrylate and methacrylate monomers have been shown to form PFCAs as metabolites of microbial degradation under aerobic conditions [13, 28. 29, 30]. However, a limited number of studies have investigated the potential fate of FT-based acrylate polymers in the environment. It has been hypothesized that, in addition to landfills, fluorotelomer acrylate materials enter wastewater systems as well as surface waters. The results presented in the current section of the thesis elucidate the potential fate of fluorotelomer acrylate polymers in the latter two environmental systems.

2.4.1 Hydrolysis Study

Headspace Analysis: The experimentally observed levels of 8:2 FTOH production at pHs 4, 6, 8, and 10 are depicted in Figure 2-6. Experimental vessels had polymer concentrations of 2.7±0.3 ug/mL (ppm) of solubilized polymer, which would translate to 540±40 ug of solubilized polymer, at the beginning of the experiment. MALDI-MS results suggest that the average polymer solubilized in solution had a fluorotelomer appendage to hexadecyl appendage ratio of 1:3.1: on a mass basis, the fluorinated appendages represented 32.1% of the total mass of the polymer. Therefore, the theoretical maximum mass of 8:2 FTOH that can be recovered was 170±12 ug or 370±30 nmol of 8:2 FTOH equivalents. "FTOH equivalents" in the current thesis was previously defined in Russell et al. [15], and measures the concentration of PFCAs, FTCAs, and FTOHs in terms of FTOH concentrations. The determination of the aforementioned FT appendage to hexyldecyl appendage ratio is provided in Table 4-5 of the appendix.

30 50 • pH4 O pH6 T pH8 A pH 10 §> 40

T3 S O (D =5 30-| 5 o I O h- u_ CM 20 CO a: XI "5 a 10 J a

-•-4*- 20 40 60 80 Time (days)

Figure 2-6. Evolution of 8:2 FTOH at pHs 4, 6,8 and 10.

Owing to the structure of the model polymer, 8:2 FTOH was expected to be the first dominant product of the FT-based acrylate polymer yielded upon degradation. In the hydrolysis study, the results suggest that the formation of 8:2 FTOH from hydrolysis followed a logarithmic trend. The amount of 8:2 FTOH recovered after 80 days at pHs 4, 6, 8, and 10 were 0.88 (RSD 4%), 16.6 (3%), 19.5 (2%), and 40.5 (3%) ug respectively. The 8:2 FTOH concentrations recovered from the experimental vessels are presented in Table 2-2.

FTOH Recovered (nmol) Standard Error

pH = 4 1.9 0.1

pH = 6 36 2

pH = 8 42 2

pH=10 87 4

Table 2-2. 8:2 FTOH Equivalents recovered from Hydrolysis Experimental Vessels

31 These values would translate to 0.55±(SE 0.04)%, 10.1 ±0.7%, 12.2±0.8%, and 25±2% respectively of degradation of polymer owing to hydrolysis, assuming that every fluorinated appendage of the polymer was accessible to degradation. Corrected for 8:2 FTOH recoveries in the extraction and analysis procedure, 8:2 FTOH evolution from the ph = 4, 6, 8, and 10 experimental vessels would be 0.63±0.04%, 11.5±0.8%, 13.9±1%, and 29±3% respectively. The results are summarized in Table 2-3. Tables containing the amounts of 8:2 FTOH from the experimental vessels collected at each time point of the experiment are provided in section 4.3 of the appendix.

% of theoretical amount of Standard Error 8:2 FTOH recovered after degradation

pH = 4 0.63 0.04

pH = 6 11.5 0.8

pH = 8 13.9 1

pH =10 29 3

Table 2-3. Hydrolysis Study - percent of theoretical amount of 8:2 FTOH recovered

The results indicate that the solubilized polymer undergoes base catalysed hydrolysis and is susceptible to hydrolysis at environmentally relevant pH conditions. No 8:2 FT acrylate was detected during the experiment suggesting that 8:2 FT acylate is not a degradation product of FT- based polymer hydrolysis, and further supporting the fact that residuals did not affect experimental results. 8:2 FT acrylate is an important residual as it is used directly in the synthesis of FT-based acrylate polymers.

19F NMR Spectroscopy: 19F NMR spectroscopy analyses were used to further understand the degradation extent of the fluorotelomer acrylate based polymer. Four samples were analysed in this investigation: pH = 4 solution with the FT polymer at day 0, pH = 4 solution with the FT polymer at day 80, pH = 6 solution with the FT polymer at day 80, and the pH = 10 polymer

32 solution with the FT polymer at day 80. A summary of the results is provided in Table 2-4. 19Fr NMR spectra of the described samples are provided in the appendix, section 4.2.

POLYMER DAY •CF3 I.S. -81ppm/ Corrected Degradation SAMPLE (-81ppm) (-58ppm) -58ppm Ratio signal signal intensity intensity

pH = 4 0 84.6±0.3 15.4±0.3 5.5±0.2 11 .O±0.3 0%

pH = 4 80 84.2±0.3 15.8±0.3 5.3±0.2 10.6+0.3 3.7±0.2%

pH = 6 80 88.2+0.4 U.9±0.4 7.4±0.3 7.4+0.3 33±2%

pH=10 80 0 100 0 0*0 100 %

Table 2-4.19F NMR analysis of FT acrylate polymer hydrolytic degradation

The intensity of the -CF3 signal from the fluorinated appendages of the polymer (-81 ppm) was compared to the intensity of the internal standard signal (-58 ppm). pH = 4 samples were prepared differently from the other pH samples in that 0.04 mL of a 1600 ppm internal standard solution was used instead of a 800 ppm l.S. solution. This analytical modification accounts for the observed intensity ratios shown in Table 2-4. Owing to the limited number of samples, the pH = 4 samples were not re-prepared.

19F NMR spectroscopy data show that high amounts of polymeric material remained in the experimental vessels buffered to pH = 4. suggesting that at pH = 4, the fluorotelomer acrylate based polymer underwent limited hydrolytic degradation. These results were supported by the observation of limited 8:2 FTOH evolution in the pH = 4 experimental vessels during the study. Spectral evidence suggests that 3.7±0.2% of the FT polymer's fluorinated appendages had been released over the 80 day duration of the study at pH = 4. The observed degradation is significant (see statistical data presented in the appendix in section 4.4) when compared to the amount of polymer present in the experimental vessels at day 0 of the hydrolysis study. 19F NMR spectral data for pH = 6 experimental vessels at day 80 showed a ratio intensity decrease of 33±2% which

33 suggests that 33±2% of the polymer's fluorinated appendages had been released. pH = 10 experimental vessels at day 80 showed no evidence of fluorinated signals except for the internal standard at -58 ppm (see Figure 4-6 in the appendix). This potentially suggests that the fluorotelomer acrylate based polymer underwent 100% degradation, in terms of release of fluorinated appendages from the polymeric backbone, under pH = 10 conditions. This phenomenon is supported in part by the observed 'leveling-off of 8:2 FTOH evolution in the pH = 10 experimental vessels over the course of the hydrolysis experiment.

MALDI-ToF Analysis: Using the procedure described in section 2.3.3, experimental samples from the hydrolysis study were analysed by MALDI-ToF, Figure 4-7 is a MALDI spectrum of the polymer solubilized in the water solution prior to the start of the hydrolysis experiment. While the synthesized polymer had a fluorotelomenhexadecyl appendage ratio on the order of 1:1, the average FT appendage to hexadecyl appendage ratio was 1:3.1 in the hydro trope/surfactant solution (the solution used in the studies). The change in ratio suggests that FT-acrylate polymers of higher alkyl content are more easily solubilized in the prepared surfactant/hydro trope solution than FT-acrylate polymers of higher fluorotelomer content.

Shown in Figure 4-8 in the appendix is the MALDI spectrum of the polymer content in the pH = 4 experimental vessels at day 80 (the end of the experiment). When compared to Figure 4-7, it can be seen that the overall polymer distribution is preserved at pH = 4, which suggests that the polymer, on the whole, is not readily susceptible to degradation at pH = 4. I lowever, the signal intensities of higher molecular weight polymers (>8500 m/z on the spectrum) are diminished and this may suggest that the degradation of higher molecular weight polymers precedes the degradation of lower molecular weight polymers. An examination of the 5500-7500 m/z spectral ranges of the two samples (see appendix) further highlights the diminished signal intensities of higher molecular weight polymers after day 80 of hydrolysis at pH = 4. The low degradation potential of the polymer at pH = 4 is supported by the low evolution of 8:2 FTOH from the pH = 4 experimental vessels, and the slight decrease in the ratio of intensities between the terminal -CF3 groups of the fluorinated appendages of the polymer as observed in 19F NMR

34 spectroscopy. The base catalysed hydrolysis of esters has been previously documented [31.32]. Figure 4-9 shows a MALDI spectrum of the polymer content in the pH = 6 experimental vessels at day 80, and displays a loss of higher molecular weight polymer species (>7000 m/z) over the duration of the hydrolysis study. The loss of polymer content as a result of pH conditions is further highlighted in MALDI spectrum of polymer content in the pH = 10 experimental vessels at day 80 (Figure 4-10) which shows a disappearance of signals beyond 2000 m/z.

Results from MALDI analysis highlight three points regarding FT acrylate polymer degradation. Firstly, hydrolytic degradation of the investigated fluorotelomer acrylate polymer is base catalysed. Secondly, high molecular weight polymers appear to be susceptible to hydrolytic degradation. This suggests that increasing the molecular weight of fluorotelomer acrylate polymers may not hinder the hydrolysis of FT-acrylate polymers. Thirdly, hydrolytic degradation of the investigated FT acrylate polymer is significant at pH = 6 and essentially complete after 80 days at pH = 10. This point is supported by the results of 19F NMR spectroscopy, and the saturation of 8:2 FTOH evolution in the pH = 10 experimental vessels over the duration of the hydrolysis experiment.

Hydrolytic Degradation Rates: 19F NMR spectroscopy and MALDI-ToF results suggest that the degradation of the investigated fluorotelomer acrylate polymer goes to completion, or near completion, in a pH = 10 water solution. However, the 8:2 FTOH evolution in the pH = 4, 6, 8, and 10 experimental vessels accounted for 0.55±0.04%, 10.4±0.7%, 12.2±0.8%, and 25±2% of the theoretical amount of 8:2 FTOH appendages present in the polymer respectively. There are possible explanations for the lower than expected recoveries of 8:2 FTOH from these experimental bottles. Firstly, though the only points of exit from the experimental vessels theoretically were through the XAD cartridges, it is possible that 8:2 FTOH was removed from the experimental vessels through other openings in the experimental set-up that were not accounted for. Secondly, the sorption potential of the FT polymer to the metal syringe through which air was delivered into the experimental vessels was not accounted for. Thirdly, 8:2 FTOH may have sorbed onto the rubber septa of the experimental vessels. Wang et al. had previously

35 shown that 8:2 telomer B alcohol sorb to PTFE septa in preference to glass surfaces [28]. Nevertheless, the near cessation of 8:2 FTOH evolution in the pH = 10 experimental vessels during the hydrolysis study coupled with 19F NMR spectroscopy and MALDI-ToF results suggests strongly that near complete to complete degradation of FT-acrylate polymers had indeed occurred at those conditions.

8:2 FTOH evolution in the pH = 6, 8, and 10 hydrolysis experimental vessels followed logarithmic trends suggesting that hydrolytic degradation of the FT polymer is first order. With support from 19F NMR spectroscopy and MALDI-MS results, and the fact that 8:2 FTOH evolution reached a plateau in the pH = 10 experimental vessels, it is believed that near complete to complete degradation had occurred to the fluorotelomer acrylate polymer at pH = 10 aqueous conditions. It would therefore be appropriate to scale the results of 8:2 FTOM evolution from all the experimental vessels relative to the results of the pH = 10 experimental vessels to calculate the first-order kinetics that govern the degradation of the FT polymer at the various pH conditions. The first-order degradation rates at various pH conditions of the FT polymer are presented in Figure 2-7 and Table 4-7. Polymer degradation trends at plls 6, 8, and 10 all exhibited statistically significant (p<0.005) pseudo first-order kinetic rates. The rates and corresponding half lives are summarized in Table 2-5. Further information is provided in Table 4-6 of the appendix. Degradation rates were not calculated for pH = 4 conditions as the polymer under those conditions had not undergone sufficient degradation needed to calculate half lives. With the scaling of 8:2 FTOH evolution relative to the pH = 10 data, the results of 8:2 FTOH evolution measured in the experimental vessels at the four pH conditions complement the pH dependency of polymer hydrolytic degradation as suggested by 19F NMR spectroscopy.

36 OpH 10

• pH8

ApH6

20 30 40 60 time (days)

Figure 2-7. Hydrolytic degradation rates of FT polymer at various pH conditions

Degradation Rate Half Life

hr standard error days standard error

pH = 4

-4 4 PH = 6 3.3*10 0.4* 10" 90 10

pH = 8 3.8*10 -4 0.4* 10~4 80 10

pH = 10 2.8*10 •3 0.1*10" 10.6 0.6

Table 2-5. Degradation Rates and Half Lives of FT polymer at various pH conditions

37 Contrary to the results suggested by Russell et al. [15] and Van Zelm et al. | 17] who suggested that fluorotelomer acrylate polymers have an environmental half-life of 1000-2000 years, the results of the currently described study suggest that FT acrylate polymers may undergo relatively rapid hydrolytic degradation even at environmentally relevant pH conditions. This suggests that FT acrylate polymers are susceptible to degradation in environmental surface waters.

2.4.2 Wastewater Study

Viability Test: sludge activity was tested in three 200 mL active mixed liquor vessels that underwent continuous aeration during the experiment. 1 mL of a 2500 ppb stock solution of 6:2 FTUCA in methanol was spiked into these vessels at day 33 and again at day 57 of the experiment. 6:2 FTUCA was selected as the compound to probe microbial viability owing to its involatility and projected transformation to PFHxA. The evolution of PFHxA after both spikes was an indication that the mixed liquor was active over the duration of the experiment. The transformation of 6:2 FTUCA and subsequent evolution of PFHxA are shown in Figure 2-8.

PFHxA 6 2 FTUCA

3 4

C/) % 3

CO £ 2

c I 1 <

0 #0—0-

Figure 2-8. Transformation of 6:2 FTUCA to PFHxA - Viability Test

The viability of the pH = 6 mixed liquor medium was monitored with the addition of 6:2 FTUCA to the control vessels that contained only aerated active mixed liquor. The degradation of 6:2

38 FTUCA to PFHxA was expected, and therefore the formation of PFHxA was monitored by LC- MS/MS. It was shown that 25±1% of the 6:2 FTUCA was transformed into detectable PFHxA 15 days after each addition. 100% recovery was not believed to have been possible as other products besides PFHxA would have formed from the degradation 6:2 FTUCA The results of the viability test supported the assumption that the sewage sludge in the experimental vessels was active during the entire study. Additional information is provided in the appendix in section 4.7.

Headspace Analysis: The results from the headspace analysis of the "NON-ACTIVE mixed liquor and biocide with 10 ppm polymer" vessels (control set 2) and the '"test" vessels are provided in Figure 2-9.

2.0

1.8i • - 1.6 11111 A 3 1.4 5 III Microbial S 1.2 £ degradation

P 0.8 $ t ££ 5 5 5 5 CM 0.6 CO 5E s Hydrolytic 0.4 cP degradation o 0.2 V o.o Joo- 0 20 40 60 80 100 120 Time (days) Figure 2-9. 8:2 FTOH evolution in Control Set 2 and Experimental Vessels

Experimental and Control vessels were aerated prior to the addition of the solubilized FT polymer into the vessels. No evolution of 8:2 FTOH in any of the vessels was noted prior to day 0 of the experiment. "NON-ACTIVE sludge*' denotes sewage sludge that has been autoclaved and mixed with biocide. The formation of 8:2 FTOH in "NON-ACTIVE sludge WITH polymer" (control set 2) can be accounted by hydrolytic degradation, a potential mode of fluorotelomer polymer degradation that was described in section 2.4.1. More importantly, however, is the

39 observed formation level of 8:2 FTOH in the "test" vessels two times greater than that of "control set 2". These results show that microbial activity is also a polential degradation pathway of the FT-based acrylate polymers.

The headspace analyses of control sets 1, 3, and 4 (see Table 2-1) showed no evolution of 8:2 FTOH nor 8:2 FTOH acrylate beyond that of background noise supporting the fact that no detectable residuals were present in the experimental vessels. Similarly, no target analytes of the aqueous media in these vessels were detected beyond those of background levels. Background levels of all experimentally relevant analytes were established through the analyses of these control vessels. Figure 2-9 suggests that the initial degradation of an FT polymer in a microbial environment is much greater than in a hydrolytic environment. For instance, the amount (ng) of 8:2 FTOH collected in the "active mixed liquor with polymer" vessels (the experimental vessels) by day 2 greatly exceeded the amount (ng) of 8:2 FTOH collected in control vessels 2 over the entire study; control vessels 2 were believed to model the hydrolytic degradal ion potential of the FT polymer in mixed liquor sewage sludge. Figure 2-9 provides support for the hypothesis that microbial degradation of the solubilized FT polymer occurs in environmental conditions. It is believed that solubilized polymer that was immediately accessible was completely degraded within the first 10 days of the experiment. The subsequent evolution of 8:2 FTOH was due to the release of polymer, over time, from the sewage organic matrix. A comparison of the aggregate amounts of 8:2 FTOH collected at each time point from the control and experimental vessels in wastewater sewage studies is provided in the appendix in Table 4-9.

Aqueous Analysis: PFHxA, PFHpA, PFOA, PFNA and PFOS maintained steady background concentrations of 0.6ng/mL (RSD 10%), O.Ong/mL, 0.7ng/mL (27%), 0.5ng/mL (25%) and 0.5ng/mL (27%) in the control sludge vessels respectively. PFDA and PFUnA were detected, but not above the LOQ. 8:2 FTCA and 7:3 FTCA were occasionally detected but were not quantifiable. Highlighted in Figure 2-10 are the amounts of some of the monitored analytes over the course of the experiment. The graphs depict method blank corrected data. The amounts of the

40 "test" vessels are indicated by the black dotted series. All other series correspond to the various control vessels.

0 20 40 60 80 100 120 140 160 0 20 40 60 80 100 120 140 160 Time (days) Time (clays)

0 20 40 60 80 100 120 140 160 0 20 40 60 80 100 120 140 160 Time (days) Time (days)

Figure 2-10. Amounts of 8:2 FTOH metabolites detected in Sample Vessels (a) PFHxA; (b) PFHpA; (c) PFOA; (d) 8:2 FTUCA.

8:2 FTUCA (Figure 2-10d) showed an initial increase in concentration (in "test" vessels only) that peaked at approximately 5.5 days into the experiment; this was followed by a subsequent decrease in concentration to background levels. The increase and decrease in concentration of 8:2 FTUCA coincided with the observed subsequent increase in concentration of PFOA in the experimental vessels (Figure 2-10c). The time of peak analyte formation was calculated for

41 PFHxA, PFHpA, and PFOA by fitting the data to the 2D sigmoidal function presented in section 2.3.8. The results suggest that the peak times of PFHxA, PFHpA, and PFOA formation were 12±2, 10±2, and 11 ±2 days respectively. The uncertainties associated with the values represent the spread of the data around the value (variable c).

The evolution of PFHxA has been previously noted in the degradation of 8:2 FTOH in aerobic soils [33] and it was postulated that the production of PFHxA results from the decarboxylation of 7:3 FTUCA, a suspected degradation product of 8:2 FTUCA [33]. However, unlike PFHpA and PFOA. a second increase in PFHxA concentration was observed at approximately 80 days into the study before reaching steady-state concentration by the end of the study. Though unanticipated, the observed increase could have been due to the aforemenl toned processes. In analyzing the purity of the starting material 8:2 FT acrylate, it was discovered that 6:2 FT acrylate was present in the starting material - albeit in exceedingly small (<0.5%) concentrations. Following similar degradation pathways as 8:2 FTOH, 6:2 FTOH would lead to the evolution of 6:2 FTUCA and PFHxA could be accounted for in part by the incorporation of impurities present in the starting monomeric materials into the synthesized polymer during the polymerization process. Support for the presence of 6:2 FT acrylate impurities can be found in Table 4-5. Highlighted in the table is a prominent m/z ratio that cannot be attributed to any combination of 8:2 FT acrylate and hexadecyl acrylate; however, an oligomer consisting of three 6:2 FT acrylate components has a mass that corresponds with the unidentified m/z ratio. In addition, 6:2 FTOH was observed intermittently during the hydrolysis and wastewater studies, but not consistently enough to have its concentration monitored over time. The evolution of PFHpA (Figure 2-10b) has been postulated to evolve from the breakdown mechanism of 8:2 FTOH -^ 8:2 FTUCA ^ 7:3 FTUCA ^ PFHpA [29]. Nabb et al. have also speculated the possibility of PFHpA production from 8:2 FTCA [34] and Butt et al. have shown that PFHpA can form from 7:3 FTCA (a potential degradation metabolite of 8:2 FTOH) degradation [35]. The degradation of 8:2 FTOH to PFOA has been previously documented in the literature [12, 13, 34], and although 8:2 FTCA was not detected in this current study, it was assumed that the transformation of 8:2 FTCA to 8:2 FTUCA was rapid [36]. In addition, no sample recorded an

42 evolution of PFNA beyond background concentrations suggesting that alpha-oxidation of 8:2 FTCA as a result of microbial activity [11] had not occurred. This finding has been observed in previous studies which investigated the degradation 8:2 FTOH in aerobic sewage sludge [13,29].

In the wastewater study, 1.5±0.2% of the 8:2 FTOH equivalents delivered into the experimental vessels was recovered in the form of 8:2 FTOH and its degradation products. As previously noted, the theoretical amount of 8:2 FTOH in the experimental vessels was 170±12p.g or 370±30 nmol. 8:2 FTOH recovered in headspace analysis of experimental vessels equaled 3.6±0.1 nmol (black series of Figure 2-9), while PFHxA, PFHpA, and PFOA recovered in aqueous analysis of experimental vessels (Figure 2-10), when translated into 8:2 FTOH equivalents [15], were approximately 1.0, 0.7, and 1.0 nmol after background correction. An aggregate total of 6.3nmol of 8:2 FTOH equivalents were recovered therefore, which accounts for 1.5±0.2% of the total amount of 8:2 FTOH equivalents available. Remarkably, most of the degradation to the polymer occurred within the first 20 days of the experiment, as noted by the "plateau-ing" of 8:2 FTOH evolution in the experimental vessels 11 days after the start of the experiment, and the steady concentrations of PFHxA, PFHpA, and PFOA observed in the aqueous phase 20 days after the start of the experiment. These results suggest that microbial degradation of available FT-based polymer is rapid in the wastewater system. Any increase in concentration of PFCAs measured in the aqueous phase, and amount of 8:2 FTOH measured in the headspace was from the degradation of polymeric material that had sorbed rapidly to wastewater organic matter.

By the end of the wastewater study, the amount of 8:2 FTOH that had evolved from the hydrolysis of the polymer alone (white series of Figure 2-9) was 1.8±0.1 nmol, or 0.40±0.02% of the amount of 8:2 FTOH equivalents delivered in the system. Compared to the amount of 8:2 FTOH recovered in the pH = 6 experimental vessels (11.5±0.8%) in the hydrolysis study presented in section 2.4.1, the amount of 8:2 FTOH recovered in the vessels that modeled polymer hydrolysis in wastewater was 33 times lower.

43 The apparent low recoveries in the wastewater study, as compared to the hydrolysis study, can be explained as follows. Firstly, it is conjectured that given the amount of organic content in the wastewater study, sorption of 8:2 FTOH to the sewage sludge organic material preventing 8:2 FTOH from volatilizing into the headspace had occurred. In addition to 8:2 FTOH sorption, it is hypothesized that sorption of the fluorotelomer acrylate polymer to the sewage sludge organic material had occurred, thus preventing the polymer from undergoing degradation. First, to determine if 8:2 FTOH sorbed to sewage sludge, 8:2 FTOH standard aliquots were added to deactivated mixed liquor vessels and immediately aerated. After four days of aeration, 77±3%) of the original 8:2 FTOH amount spiked into the vessels were recovered, suggesting that 8:2 FTOH sorbs to sewage sludge. Subsequent aqueous analysis of these test vessels did not show any evolution of suspected 8:2 FTOH degradation metabolites beyond background levels. Next, 8:2 FTOH aliquots were spiked into deactivated mixed liquor systems and the systems were left unaerated for a day. Air was then purged through the systems until 8:2 FTOH recovery had reached saturation. Here, the recovery of 8:2 FTOH from the test vessels was 22±3%. Corrected for the extraction efficiency of the method, the amount of 8:2 FTOH recovered after 0 and 1 days of interaction with sewage sludge were 87±3% and 25±3% respectively. Results are summarized in Table 2-6 and demonstrate that 8:2 FTOH potentially sorbs to the organic material in the mixed liquor aqueous medium. Sorption of 8:2 FTOH to organic matter has been previously documented in the literature [37] and partially accounts for the observed low recoveries of fluorinated compounds in the wastewater study.

Polymer sorption to sewage sludge was monitored by 19F NMR spectroscopy. Test vessels containing 190mL of autoclaved pH = 6 sewage sludge wastewater were spiked with 10 mL each of the prepared 54±5 ppm polymer solution. Three time points were taken: 0.042 day, 2 days, and 7 days post polymer solution addition. The results are summarized in Table 2-6. Supporting information is located in the appendix in section 4.8. Using the results of the pH = 4 polymer solution of the hydrolysis experiment at day 0 (Table 2-4) as the reference, 71 ±2%, 62±2%, and 54±2% of the FT polymer were recovered from the experimental vessels after 0.042 day, 2 days, and 7 days respectively. The results suggest that, in addition to 8:2 FTOH sorption to sewage

44 organic matter, FT polymeric material sorbs to sewage organic matter rendering the polymeric material inaccessible to immediate degradation.

8:2 FTOH Sorption to Sewage Sludge (GC-MS)

Day % recovered SE

0 87 3

1 25 3

Polymer Sorption to Sewage Sludge (19F NMR)

Day -CF3 LS. -81ppm/-58ppm (-81 ppm) signal (-58 ppm) signal intensity intensity

0.042 88.6±0.3 11.4+0.3 7.8±0.2

2.000 87.2±0.1 12.8+0.1 6.8±0.1

7.000 85.5±0.2 14.5±0.2 5.9±0.1

Table 2-6. 8:2 FTOH and Polymer Sorption to Sewage Organic Matter

As mentioned previously. l.5±0.2% of the 8:2 FTOH equivalents delivered into the wastewater experimental vessels was recovered in the form of 8:2 FTOH and its degradation products, while the amount of 8:2 FTOH that had evolved from the hydrolysis of the polymer alone (white series of Figure 2-9) was 0.40±0.02% of the amount of 8:2 FTOH equivalents delivered in the system. It has been demonstrated that these low recoveries are at least partially accounted for by sorption processes. Nevertheless, in observing relative amounts of 8:2 FTOH equivalents yielded in the wastewater control 2 and experimental vessels, it is suggested that hydrolytic activity accounts for up to 27±3% of the observed degradation of an FT-based polymer in a wastewater environment. Given the "plateau-ing" of evolution of 8:2 FTOH. and concentrations of PFCAs in the experimental vessels, it is probable that FT-based polymers available to degradation completely and rapidly degrade in a wastewater environment. 45 2.5 Environmental Implications

Hydrolysis and wastewater mediated studies were performed to investigate the degradation potential of an in-house synthesized FT-based acrylate polymer model solubilized in water and removed of residual compounds. The findings in the hydrolysis study suggest that FT-based acrylate polymers are susceptible to hydrolysis, as supported by the increase in 8:2 FTOH evolution with increasing pH. The site of degradation is believed to be at the ester bonds that link the fluorinated and aliphatic side-chain groups to the polymer backbone chain. The wastewater mediated study suggests that FT-based acrylate polymers solubilized in solution are highly susceptible to biodegradation. This is demonstrated by the evolution of 8:2 FTOH in the "test" vessels above what can be accounted for by hydrolysis, and also the increase in concentration of various 8:2 FTOH degradation products over the study. In fact, the results suggest that complete degradation of accessible polymer occurred within the first 20 days of the study. However, FT- polymers also show high potential to sorb to organic matter with slow release over time. With 80% of the 5000 to 6500 tons of industrially manufactured FTOHs going toward the production of fluorinated polymers, it would be important to continue to evaluate the potential contribution of FT-based polymers to the environmental PFCA burden.

2.6 Acknowledgements

The following individuals and organizations are acknowledged for their assistance: 1. Dr. Daniel Jones of Michigan State University for MALDI-ToF analysis suggestions 2. Dr. Bill Coggio of Dyneon for valuable discussion on polymer synthesis 3. Dr. Richard Thomas of Omnova for discussion on polymer synthesis 4. Wellington Laboratories (Guelph, ON) for their generous donation of labelled standards 5. Environment Canada for financial support

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[27] Satoh, K.; Nakazumi. H.; Morita, M. Novel fluorinated inorganic-organic finishing materials for nylon carpeting. Textile Res. J. 2004. 74, 1079-1084.

[28] Wang, N.; Szostek, B.; Folson, P.W.; Sulecki, L.M.; Capka, V.; Buck, R.C; Berti, W.R.; Gannon, JT. Aerobic biotransformation of 14C-labeled 8-2 telomer B alcohol by activated sludge from a domestic sewage treatment plant. Environ. Sci.Technol. 2005. 39, 531-538.

[29] Wang, N.; Szostek, B.; Buck, R.C; Folsom, P.W.; Sulecki, L.M.; Capka. V.; Berti, W.R.; Gannon, JT. Fluorotelomer alcohol biodegradation - direct evidence that perfluorinated carbon chains breakdown. Environ. Sci. Technol. 2005. 39, 7516-7528

[30] Dinglasan-Panlilio, M.J.; Edwards, E.A.: Mabury. S.A. Biodegradation of fluorotelomer based monomers as a source of fluorotelomer alcohols, (in preparation).

[31] Garrett. E.R. The Kinetics of Solvolysis of Acyl Esters of Salicylic Acid. /. Am. Chem. Soc. 1957.79,3401-3408.

[32] Garrett. E.R. Evidence for General Base Catalysis in an Ester Hydrolysis. 1. Hydrolysis of an Alkyl Aminoacetylsalicylate. /. Am. Chem. Soc. 1957. 79, 5206-5209.

[33J Wang, N.; Szostek, B.; Buck. R.C; Folsom, P.W.; Sulecki, L.M.; Gannon, JT. 8-2 fluorotelomer alcohol aerobic soil biodegradation: Pathways, metabolites, and metabolite yields. Chemosphere. 2009. doi: 10.1016/j.chemosphere.2009.01.033

49 [34] Nabb. L.D.; Szostek, B.; Himmelstein. M.W.; Mawn, M.P.; Gargas, M.L.; Sweeney. L.M.; Stadler, J.C; Buck, R.C; Fasano, W.J. In vitro metabolism of 8-2 fluorotelomer alcohol: interspecies comparisons and metabolic pathway refrinement. Toxicol. Sci. 2007. 100, 333- 344.

[35] Butt, CM.; Mabury, S.A.; Muir, D.C.G. Bioaccumulation and biotransformation of 8:2 FTOH in Rainbow Trout, (poster). PFAA Day II, Research Triangle Park, NC, June 2-3 2008.

[36] Myers, A.L. The Environmental Fate of Fluorotelomer Acids. MSc Thesis, University of Toronto, 2008.

[37] Liu, J.X.; Lee. L.S. Solubility and sorption by soils of 8:2 fluorotelomer alcohol in water and cosolvent systems. Environ. Sci. Technol. 2005. 39, 7535-7540.

50 Chapter Three:

Polymer Synthesis and Future Directions

51 3 Research Directions and Future Considerations

Although it is believed that the fluorotelomer polymer investigated in the hydrolysis and wastewater sewage studies presented in chapter 2 of the current thesis is an adequate model of the fluorotelomer acrylate based polymers used in industry, it differs nevertheless from industrial fluorotelomer polymers in that the fluorotelomer polymer used in the presented investigations is composed of only two monomers whereas industrial fluorotelomer polymers are composed of three, four or even five monomers. The most outstanding issue is that the fluorinated appendages on the model FT polymer are potentially more sterically hindered than those of industrial FT polymers. With the incorporation of more monomers in industrial FT polymer syntheses, there are, in essence, more monomeric "spacers" in between each fluorinated appendage. Lower steric hindrance associated with each fluorinated appendage in an industrial polymer would suggest a higher degradation potential and higher degradation rate in comparison to the model FT polymer used in the current studies. Therefore, this suggests that the FT polymer degradation rates and degradation potential presented in the current thesis are, indeed, conservative estimates of industrial FT polymer degradation rates and potential. To model the degradation patterns of industrial FT polymers more closely, a polymer that is more similar to those used in industry as the one used in the studies presented in the current thesis should be synthesized.

3.1 Polymer Synthesis and Characterization

The synthetic route of the new model FT acrylate based polymer was inspired by two patents documenting the synthesis of fluorotelomer acrylate based polymers [ 1.2]. The new model polymer ideally has a distribution of the following nature: 40-75% of the appendages in this new polymer by weight will be fluorotelomer acrylate based, 10-35% of the appendages by weight will be vinyhdene chloride based, and 10-25% of the appendages by weight will be butyl acrylate based. A schematic diagram of new model polymer is presented in Figure 3-1.

52 Figure 3-1. Schematic of New Model Polymer

The polymer synthesis occurred in a three-neck round bottom flask equipped with a stir-bar and a dry ice condenser. The surfactants dodecylamine and dodecylamine hydrochloride, and the chain transfer reagent hexadecyl thiol were added to 150mL of Barnstead E-pure water with a resistivity of 18 MQcm"1. To this solution. 15.0g of 8:2 FT acrylate (CAS 27905-45-9) and 8.0g of butyl acrylate (CAS 141-32-2) were added, and the mixture was emulsified by agitation. The emulsion was added to the round bottom flask reaction vessel, and the system was purged with nitrogen gas for two and a half hours prior to synthesis at a temperature of 5 degrees Celsius. After two and a half hours of system purging, a solution containing 7.0g of vinyhdene chloride (CAS 75-35-4) dissolved in dry ice cooled acetone was introduced into the reaction vessel. A second solution containing l.Og of 2,2'-azobis(2-methylpropionamidine) dihydrochloride initiator dissolved in Barnstead E-pure water also was introduced into the reaction vessel. Over the course of one hour, the temperature of the reaction vessel was brought then to a steady temperature of 50 degrees Celsius. The polymerization reaction was allowed to proceed for 15 hours. Solid polymer product was collected via filtration. Polymer solubilized in solution was recovered by removing the water solvent. The yield of the synthesis was between 50 to 60%.

53 The synthesized fluorotelomer acrylate based polymer was then characterized using differential scanning calorimetry (DSC) and MALDI-MS. A DSC spectrum of the synthesized polymer was obtained from a 2920 MDSC V2.6A instrument with a DSC-standard modulated module. The temperature scanning range was -30°C to 180°C. The heating cycle was completed at a rate of 10°C/min, followed by a cooling cycle. It was determined by DSC that the polymer has a melting point of 67.8°C and a crystallization point at 55.3°C. There was no detection of a glass transition temperature (Tg), and it is hypothesized that the Tg is below -30°C and beyond the capabilities of the instrument. The DSC spectrum is provided in Figure 4-15 in the appendix.

Mass spectra of the synthesized polymer were acquired by using a Waters Micromass MALDI micro MX1M time-of-flight mass spectrometer in linear and positive ion modes. The backing/inlet and analysis pressures were set at 10"' mbar and 10" mbar respectively; the flight tube voltage was set at 12,000V; a 337 nm laser was used for data acquisition and fired at a frequency of 5Hz. 10 scans at a scanning rate of 0.6 seconds per scan comprise a spectrum, and a minimum of 40 spectra were acquired. Mass to charge ratios of less than 1000 were suppressed during analyses. In preparation for MALDI analysis, sample wells were initially coated with a thin film of graphite aqueous mixture. The mixture was then applied to the sample wells and allowed to air-dry, leaving behind a thin coating of graphite. A solution of lOmg/mL of Dithranol and lmg/lmL of lithium trifluoroacetate was then applied to the graphite coated sample well. A sample of the newly synthesized polymer dissolved in chloroform was then applied to the sample well, and the sample was allowed to dry thoroughly prior to analysis.

The synthesized polymer showed slight solubility in chloroform, tetrahydrofuran, methyl-tert-buytl ether, and acetone. The MALDI spectrum of the synthesized new model polymer is presented in Figure 3-2.

54 ICflC t533 3080 35GI? MMffl fsoc >an ' 85oo -nee ••sun woo a?oo

Figure 3-2. MALDI Spectrum of New Model Fluorotelomer acrylate based Polymer

The FT acrylate polymer is distributed over a mass range, most of which lie within m/z 1000 to 7500. The M* and M„ of the synthesized polymer are 4186.22 and 3351.75 respectively; this yields a polydispersity index of 1.249. The most prominent peaks of the spectra are separated by the mass of an 8:2 fluorotelomer acrylate component of the polymer. For example, it has been calculated that the m/z ratio 1302.78 contains one 8:2 FT acrylate monomer components while m/z ratio 6982.78 contains twelve 8:2 FT acrylate monomer components. The MALDI spectrum further revealed that a similar pattern of polymer signals occurs in between every prominent signal in the spectrum. As these patterns repeat themselves in the spectrum, each unit hence will be called a "repeat" unit. A visual example of the repeating units is represented in Figure 4-16 of Appendix B. Each of the polymer signals was identified as a unique combination of 8:2 FT acrylate, butyl acrylate, and vinyhdene chloride. MALDI spectra supporting the identity of each polymer signal is provided in

55 Figure 4-17 and Figure 4-18 provided in the appendix. A summary of the monomeric components of each polymer signal, and their relative abundances within each individual polymeric "repeat" unit is provided in Figure 3-3.

JISSMBO 100- X = £ 8:2 FT acrylate X = 4 X 3 Y = # butyl acrylate 4 Z= # vinyhdene chloride 40.6% % abundance in unit

i i idte^JULJUUbaw9*» "t«»Jfi»3 . .S?3. ^"tS^Aww^*

X X 3 4 : 4 4 x X X 3 x > 7.8% 5 6.9*. 4 5 I 2870 202 2 S X 4 3 X 3 4.6% 4.2% 4 5 S.0% ' 3.8% .MUS83 5 ! * ! » ima 301 x I x I l a«ss a*? 1.4% / \ A * s 0.8% A 3 y KJ X\A* , *w : 3 V*M# ^^W^, V/ / ^ 1 f#ffrf '[•'•"'•I1'"'1'!'" ' i iv| inn' "'''!'' "' ITftypffTt i 2800 i320 2&30 2862 2<3Ja ."Mi 2A80 2^83 3QC0 3023 3C41 2^63 MOO 3060 30SP 31 DO 3120

Figure 3-3. Summary of the identity of FT acrylate polymer signals

In Figure 3-3, "x" refers to the number of 8:2 FT acrylate monomers in the polymer "repeat" unit and will vary from one "repeat" unit to another. The unit shown in Figure 3-3 contains four 8:2 FT acrylate monomer components. The number below "x" refers to the number of butyl acrylate monomers incorporated into the particular polymer signal; the third number refers to the number of vinyhdene chloride monomers incorporated into the particular polymer signal. It is believed that the

56 newly synthesized FT acrylate based polymer has structural characteristics that are similar to those of industrial FT based polymers.

3.2 The Degradation of Fluorotelomer Acrylate Polymers in Soils

It has been estimated that one-third of the fluorotelomer acrylates produced industrially, most of which is incorporated into polymer synthesis, is ultimately released into wastewaters [3]. Wastewaters are treated before being delivered into natural waters, leaving behind organic solids, or sewage sludge, at the treatment plant. Owing to its high nitrogen and phosphorous content and carbonmitrogen ratio [4,5], sewage sludge is often used as fertilizer on agricultural fields and benefits soil quality from nutritional, physical, chemical, and biological standpoints. However, despite these benefits, sewage sludge - being the end product of the sewage treatment cycle - is a source of accumulation of many naturally occurring, and anthropogenic compounds that did not undergo degradation in the sewage treatment process. Another concern regarding the application of sewage sludge to agricultural soils is the indirect transfer of heavy metals, which accumulates in the sludge during the treatment process, to the fields [6]. Taking a cautionary approach, many countries of the European Union have opted to dispose sewage sludge by other means in lieu of land applications. North America, on the other hand, continues to use land applications as the main method of sludge disposal with 41% of the biosolids generated in the United States annually being applied to fields as fertilizer [6].

Given the high production of fluorotelomer acrylate based polymers and their disposal into wastewaters, it is quite probable that fluorotelomer acrylate based polymers would be inadvertently applied to agricultural soils as part of the sewage sludge fertilizer application process. It is estimated that, in Ontario alone, 120,000 tons of sewage sludge are applied annually on 15,000 hectares of agricultural farm fields. Agricultural soils consist of a variety of bacterial and microbial populations with the highest population densities of these organisms existing at the soil-plant root interface known as the rhizosphere. Through the photosynthetic process, plants excrete, at their roots, nutrients on which these populations sustain. In turn, these populations promote plant growth through numerous activities including nitrogen fixation, antibiosis of potentially plant harming

57 organisms, soil stabilization, and water uptake [7]. The addition of fertilizers such as sewage sludge would serve to promote the health of these populations in the soils, thereby promoting the health of agricultural crops. Given the existence of microbial populations in soils, it would be important to evaluate the potential fate of fluorotelomer acrylate based polymers in agricultural settings.

The work of Russell et al. is widely regarded as the first attempt to understand the biodegradation potential of fluoroacrylate polymer products in soil environments [8]. Based on their results, it was concluded that fluorotelomer acrylate polymers do not readily undergo degradation in soil environments and have half-lives of one to two millenia. Unfortunately, residual materials were not removed from the test polymer, and it would have been impossible to differentiate degradation coming residual products, and potential degradation originating from the tested fluoroacrylate polymer. In addition, experimental conditions did not model natural conditions because the soil environment used in the experiment was devoid of vegetation growth. Soil microbes exist symbiotically with plants and an absence of plant growth discourages soil microbial activity. Furthermore, soil microbe activity was not evaluated. Lastly, the concentration of the investigated polymer during the experiment was not determined. The currently described study serves to test a residual-free fluorotelomer-based acrylate polymer in an environment similar to a typical North American agricultural farm field.

3.2.1 Residual Removal and Polymer Solubility

The new polymer precipitate collected post-synthesis was continually vacuum suctioned, and washed with an 80:20 methanokwater solution for 14 days. After the washes, the polymer was collected in a 250mL beaker, and melted by immersing the beaker in a 95 degree Celsius oil bath. A gentle stream of in-house air filtered by a carbon trap was passed over the surface of the melted polymer to increase the rte of residual removal. This procedure continued for consecutive 20 days and any volatile fluorotelomer residual compounds were expected to be removed within this period. After the 20 day period, 0.1892±0.0001g of the polymer was tested for residuals by re-melting the fraction in another glass vessel. A gentle stream of in-house air filtered by a carbon trap was passed over the surface of the melted polymer for 3 consecutive days, and any volatile compounds were

58 collected on XAD cartridges. XAD cartridges were then extracted and analyzed according to the procedure outlined in section 2.3.6. After the 3 days, the masses of 8:2 FTOH and 8:2 FT acrylate collected on the XAD cartridges were approximately 0.00022% and 0.00014%' respectively of the mass of the fraction tested. The values suggest that residuals were effectively removed prior to the start of the experiment. The polymer was solubilized in a water:acetone:chloroform mixture in an 80:10:10 ratio after vigorous shaking and sustained heating at 70°C. Dodecylamine was present in the water fraction at a 10 mg/mL concentration.

3.2.2 Experimental Set-Up

Two control sets and two experimental sets are used in this experiment. Descriptions of the vessels are provided in Table 3-1.

Experimental Sets Number of Vessels

Control Sets

Soil + Plant + Sludge 12

Soil + Polymer 12

Test Sets

Soil + Plant + Sludge + Polymer 12

Soil + Polymer + Plant 12

Table 3-1. Soil Study: Controls and Experimental Vessels Centrifuged biosolids, solid sewage material remaining at the end of the wastewater treatment process, were collected from Ashbridge's Bay Wastewater Treatment Plant in Toronto, Ontario. It is this organic waste material, in its diluted form, that is typically applied to agricultural fields. A 20% (w/v) biosolid aqueous solution (henceforth referred to as sewage sludge) was made and mixed, by using an Odjob M concrete mixer, with sandy loam soils at a rate of 10 metric tons per acre, or 16g of sludge per kilogram of soil. Sandy loam soils were collected from an agricultural field in Cobourg. Ontario.

59 Medicago truncatula is used as the model plant in this study and grown in sandy loam soils. Soils in all vessels will be inoculated with rhizobia prior to planting. The study will span a 4 month period from plant seeding to apotosis. 0.050g of the solubilized FT polymer is dosed into approximately 600g of soil in the appropriate pots. Three vessels per control and experimental sets will be sacrificed per time point - 0 months. 1.5 months. 4 months and a timepoint beyond 4 months that has yet to be determined. The evolution of suspected 8:2 FTOH degradation products over the experiment will be monitored for in the soil. In addition to monitoring the soils for FTOH, PFCA and FTCA evolution, the medicago truncatula plants will also be analyzed for 8:2 FTOH metabolites; through this, the utility of plants as a remediation method of perfluorinated chemicals in soils will be evaluated. This project is of immediate interest.

3.3 Thermal and Mechanical Degradation

Though the evaluation of the atmospheric and microbial degradation processes of the 8:2 fluorotelomer acrylate monomer and polymer deserve scientific attention, an equally important form of degradation that may eventually be a source of fluorinated chemical release is polymeric thermal degradation. Besides their common applications in consumer goods, national defence departments have begun to investigate the utilities of fluorinated polymers as additives in blast, chemical, and biological resistant coatings on land, air and water crafts pT|. Given the natural dangers that come with protecting the sovereignty of one's nation, it is undoubtedly true that these motor devices may potentially be subjected to extreme physical stresses such as high heat, high speeds, and strong impacts. Beyond these potential applications, fluorinated polymers are also seeing new utility in broadband technologies such as optical networking owing to their low transmission losses at telecommunication operating wavelengths (1310 and 1550nm) [10].

In the first known study of the thermal degradation processes of fluorotelomer-based acrylate polymers, it was suggested that high thermal conditions, such as those observed in municipal incinerators, would lead to the destruction of polymeric compounds and therefore suppress the formation of PFCAs [11]. However, the study did not analyze for the formation of potential precursors, including alcohols, aldehydes, or acrylate fragments, of PFCAs. In another study,

60 however, fluorinated polymers with a chemical architecture similar to those described for fluorotelomer-based polymers were shown to be labile to heat stresses (450 to 750 degrees Celsius); in addition, thermal degradation occurred most often at the main chain leading to the degradation products of the monomer, dimer, and trimer forms the units used in the polymeric synthesis [10]. An investigation into the thermal lability of poly-n-alkyl acrylates has shown that main chain alcohol compounds are produced [12]. The suggested mechanism of this degradation is provided in Figure 3-4 where the hydrogen atom on the carbon adjacent to the carbon with the hydroxyl group would first experience intramolecular hydrogen bonding with the carbonyl oxygen. This would facilitate a transfer of electrons from bond to bond resulting in the eventual formation of an alcohol and ethylene group containing the "R" tail: X

H2 I H2 I H2 I H2 I -C C- -C C- -C C- -C- + H2C= -C- -c- H

>r O' o^o O

X=HorCH3

Figure 3-4. Proposed mechanism of thermal degradation of 8:2 FT acrylate polymers

For the purposes of fluoro-telomer degradation however, attention should be drawn to the other degradation product - the olefin - for which the "R" group can be replaced by a suitable perfluorinated or fluorotelomer chain. If such a thermal degradation process were to occur in the environment, it is foreseeable that the ethylene would atmospherically degrade by the route shown in Figure 3-5 where the hydroxyl radical would preferentially add to the double bond. This is followed by O2 oxidation and finally formation of a perfluorinated aldehyde:

zCH, OH 0 R, .OH H R2—-\ 2C

H Figure 3-5. atmospheric oxidation pathway of ethylene thermal degradation product

61 The resulting perfluorinated aldehyde would require only one more appropriate oxidative step to be rendered a PFCA. Though this mechanism has not been substantiated, a kinetic and mechanistic study on atmospheric oxidation of the fluorinated 4:2 and 6:2 olefins suggested that this is a very probable degradative pathway of this product of thermal degradation [13]. Regardless, studies for this proposed mechanism of FT-based polymer degradation would clearly need to include an evaluation of the physical characteristics of the generated ethylene species such as volatility, its partitioning tendencies, and finally its susceptibility to initial OH radical addition at the double bond. Though the mechanism presented in Figure 3-5 bypasses the formation of FTOHs, it is foreseeable that thermal degradation of FT-based polymers could potentially lead to the formation of the alcohol species [10]. In the mechanism proposed in Figure 3-6. thermal degradation would initially lead to the fragmentation of the main chain rendering alkyl radicals on the main carbon chain. The structure would then electronically re-arrange itself until the radical is found on what once was a carbonyl group. This oxygen would then attack the carbonyl of the adjacent side chain thereby eliminating the RO group of the attacked side chain from the polymeric fragment:

R R R ? s R2 2 Ra R2 R2 R2 Figure 3-6. Proposed mechanism of FTOH evolution from polymeric thermal degradation The RO radical would easily acquire a hydrogen atom by abstracting a hydrogen atom from an alpha carbon in the main chain and in doing so would proliferate the production of RO radicals and therefore ROH until the polymer is fully cyclised and devoid of "R" tails. In an open air environment, the resulting FTOH would accordingly escape into the troposphere and be oxidized according to previously hypothesized mechanisms. To investigate the viability of the mechanism presented in Figure 3-6, the kinetics of the radical reaction would have to be determined. Moreover, the thermal threshold beyond which degradation would occur ought to be determined as this may be important in designing fluorinated species with high thermal tolerance as desired in optical networking technologies, and protective coatings. In addition to thermal stresses, mechanical

62 stresses of polymers may also have an effect on the degradation processes of fluorotelomer-based polymers.

Mechanical stresses are often imparted onto polymers during the actual processing, such as extrusion, calendaring and moulding, of polymers [14]. Of significance to fluorotelomer-based polymers is the process of extrusion where raw polymeric materials would be melted under high shear forces, pressures and heat and formed into a homogeneous liquid for further processing. In addition, elevated stresses and strains imparted to the polymeric system by processing equipment can lead to a compromised chemical structure. Generally, all polymers are extruded at least once during the manufacturing process when polymers are pelletized at the end of the polymerization reaction, or when additives and modifiers are incorporated into the polymeric system [14]. Degradation as a result of mechanical stresses may be especially important in the areas of side- chain lability, main chain stability, and even thermal stability. While it is relatively straightforward to investigate the thermal and thermo-oxidative degradation processes of a chemical compound, analysis of the effects of mechanical strains and stresses to the stability of a chemical compound are difficult as the contribution of each component of the manufacturing process would have to be accounted for. Nevertheless, the manufacturing process of fluorotelomer based polymers may influence the degradation properties of the polymers, and it may be important to investigate thermal and mechanical effects on the environmental fate of fluorotelomer acrylate based polymers.

3.4 Future Considerations

Two studies investigating the potential environmental fate of fluorotelomer acrylate based polymers were described in the current thesis: a hydrolysis study, and a sewage wastewater study. Both studies show the degradation of fluorotelomer acrylate based polymers in environmentally relevant conditions. In the hydrolysis study, significant hydrolytic degradation can occur to the polymer at environmentally pHs over time. Secondly, bacterial and microbial activity in wastewaters accelerates the fluorotelomer polymer degradation process. In the case of fluorotelomer acrylate polymers, their degradation unfortunately leads to metabolites and products that have proven toxicity, environmental persistence, and bioaccumulation potential. Based on the

63 findings presented in the current thesis, the appropriate direction would be to reassess the synthetic processes of fluorinated polymers, and develop materials that, while maintaining the desired properties, have low environmental contamination potential. Such modifications may include shifting towards shorter chained fluorinated appendages, and more stable linkages.

64 3.5 Literature Cited

T] Greenwood EJ. Lore AL, Rao NS. Oil- and water- repellent copolymers. United States Patent 4,742,140. May 3. 1988.

^2] Ralford KG, Greenwood EJ, Dettre RH. Water- and oil-repellent fluoro(meth)acrylate copolymers. United States Patent 5,344,903. September 6, 1994.

;3] Van Zelm R, Huijbregts MAJ. Russell MH, Jager T. van de Meent D. 2008. Modeling the environmental fate of perfluorooctanoate and its precursors from global fluorotelomer acrylate polymer use. Env. Tox. Chem. 27: 2216-2223.

4] Boyd SA, Sommers LE. 1980. Change in the humic acid fraction of soils resulting from sludge application. Soil Sci. Soc. Am. J. 44: 1179-1186.

5] lakimenko O, Otabbong E, Sadovnikova L. Persson J. Nilsson I, Orlov D. Ammosova Y. 1996. Dynamic transformation of sewage sludge and farmyard manure components. Agri. Ecosyst. Environ. 58: 121-126.

6] Renner, R. 2000. Sewage Sludge, Pros & Cons. Environ. Sci. Technol. 34: 430A-435A.

7] Lynch JM. 1990. The Rhizosphere. John Wiley & Sons, Chichester, UK.

8] Russell MH. Berti WR, Szostek B. Buck RC. 2008. Investigation of the biodegradation potential of fluoroacrylate polymer product in aerobic soils. Environ. Sci. Technol. 42: 800- 807.

9] Szabo JP, Hacker D, Underhill RS, Leidner J. Formulation of Polyurea coatings for blast mitigation, (in preparation)

10] Zuev VV, Bertini F. Audisio G. 2006. Investigation on the thermal degradation of acrylic polymer s with fluorinated side-chains. Polym. Degrad. Stab. 91: 512-516.

11] Yamada T, Taylor PH, Buck RC, Kaiser MA, Giraud RJ. 2005. Thermal degradation of fluorotelomer treated articles and related materials. Chemosphere. 61: 974-984.

12] Bertini F, Audisio G, Zuev VV. 2005. Investigation on the thermal degradation of poly-n- alkyl- acrylates and poly-n-alkyl methacrylates. Polym. Degrad. Stab. 89: 233-239.

65 [13] Vesine E, Bossoutrot V, Mellouki A, Le Bras G, Wenger J, Sidebottom H. 2000. Kinetic and mechanistic study of OH- and CI- initiated oxidation of two unsaturated HFCs: C4FgCH=CH2 and C6F]3CH=CH2. J. Phys. Chem. A. 104: 8512-8530.

[14] Capone C, Di Landro L, Inzoli F. Thermal and mechanical degradation during polymer extrusion processing. Polym. Eng. Sci. 47: 1813-1819.

66 4 Appendix

4.1 Section 2.3.4 - Polymer Solubility and Residual Removal

As stated in section 2.3.4. a lOmL polymer solution aliquot was concenti'ated to 0.5mL. A four point calibration curve containing points for 0.5ppth, l.Oppth, 1.5ppth, and 2.0ppth polymer solutions was used to quantify the concentration of polymer actually dissolved in solution. The calibration standards used were representative of 25ppm, 50ppm, 75ppm, and lOOppm FT polymer solutions respectively. The calibration curve is presented in Figure 4-1 and the statistical parameters of the calibration curve are presented in Table 4-1.

Concentration of polymer in prepared solution 25 o Calibration Curve • Polymer Solution m £ 20 tn c a> 15 <6 (0

Figure 4-1. Concentration of Polymer in the prepared polymer solution

67 Statistical Analysis ofl F NMR Calibration Curve R F SE of Estimates 0.9913 0.9826 1.1035 Variable Value SE t P b -0.7948 1.3515 -0.5881 0.6160 m 10.5001 0.9870 10.6386 0.0087

Table 4-1. Polymer Quantification Calibration Curve Parameters

The triangle presented in the Figure 4-1 suggests that the prepared polymer solution had approximately 27±3% of the expected concentration of polymer in solution. As a result, the prepared polymer solution most likely had a polymer concentration of approximately 54±5ppm, and not the intended 200ppm. Error bars associated with the calibration pomis were obtained by integrating the fluorine signals attributed to the internal standard (-58ppm) and the terminal CF3 group of the fluorinated appendages of the polymer (-81 ppm) multiple times. These error bars are indicative of software variability associated with signal integration, and not experimental variability. The relative integrations of the fluorinated signals are provided in Table 4-2. 0.5ppth l.Oppth l.Sppth 2.0ppth -81ppm -58ppm -81ppm -58ppm -81ppm -58ppm -Hlppm -58ppm

82.03 17.97 90.61 9.39 93.47 6.53 95.65 4.35 81.9 18.1 90.67 9.33 93.07 6.93 95.21 4.79 82.37 17.63 90.93 9.07 92.96 7.04 95.59 4.41 84.44 15.56 91.08 8.92 93.11 6.89 95.29 4.74 82.58 17.48 91.02 8.98 93.2 6.8 95.47 4.53 81.58 18.48 93.23 6.77 95.5 4.5 avg 82.48 17.53 90.86 9.13 93.17 6.82 95.45 4.55 stdev 1.02 1.03 0.21 0.21 0.19 0.19 0.18 0.19 4.7+0.3 9.9±0.2 13.7:tO. 4 21.0±0.9 Table 4-2. Integration Values of 19F NMR calibration curve of polymer concentration

68 For reference, the F NMR spectrum of the lOOppm polymer sample standard is provided in Figure 4-2 below.

Ait rex-

• 90* jart-

Figure 4-2. 19F NMR spectrum of the lOOppm polymer calibration standard

69 4.2 Section 2.3.7 - Vessel Aqueous Medium Analysis

The extraction efficiencies of both the Hansen et al. and Higgins et al. methods, as mentioned in section 2.3.7 of the thesis, are summarized in Figure 4-3. AH methods of extraction were performed in quadruplicate. Analytes were analysed by HPLC-MS/MS according to the conditions specified in section 2.3.7. • Hansen • Higgins 1.20

1.00

5 0-so e•o W 0.60

0.40 -

0.20

0.00 lllllllPFHxA PFHpA PFOA PFNA PFDA PFUnA 8:2 FTUClA 32 FTCA Analytes of Interest

Figure 4-3. Comparison of the Hansen and Higgin methods of PFCA extraction

Both methods had high recoveries for the PFCA analytes that were monitored for in the studies presented in chapter 2 of the thesis. However, the Hansen method was selected over the Higgins method owing to the amount of time needed to perform the Higgins method of extraction.

70 4.3 Section 2.4.1 - 8:2 FTOH Evolution

Amount of 8:2 FTOH (ng) collected per time point

pH4 vessels pH 6 vessels pH 8 vessels pH 10 vessels

standard standard standard standard DAY: average error average error average error average error

1 55.1 17.2 866.8 43.2 1349.5 87.4 10903.6 362.2

4.3 86.1 2.1 3306.9 216.3 4276.5 81.8 13409.1 839.8

8 50.1 1.8 2078.4 132.0 2852.9 122.8 3237.8 36.7

10.83 35.9 1.5 1259.8 85.6 1236.0 59. S 1860.2 66.7

15 48.1 2.4 1136.3 25.0 1139.5 118.4 1695.3 62.1

21 60.8 11.7 1861.2 122.8 1857.0 105.4 2427.1 67.7

29 149.9 6.6 2211.5 9.6 1890.0 51.

36 77.0 3.0 911.8 212.9 838.8 2.4 1116.9 92.4

45 72.8 3.8 660.9 8.4 1011.0 119.7 750.8 40.0

53 59.3 1.4 745.6 30.4 661.8 39.6 1065.9 39.6

60 54.7 2.6 762.1 223.4 741.1 6.7 657.9 46.3

70 56.1 9.3 651.2 294.9 825.8 53.3 253.3 45.2

80 76.4 1.7 230.3 9.9 855.5 108.8 169.8 22.3

Table 4-3. Hydrolysis Experiment: Amount of 8:2 FTOH (ng) collected per time point

71 Aggregate Amount of 8:2 FTOH (ng) collected by each time point

pH 4 vessels pH 6 vessels pH 8 vessels pH 10 vessels amount standard amount standard amount standard amount standard DAY: collected error collected error collected error collected error

1 55.1 17.2 866.8 A3.2 1349.5 87.4 10903.6 362.2

4.3 141.2 17.3 4173.7 220.6 5626.0 119.7 24312.7 914.6

8 191.3 17.4 6252.1 257.1 8478.9 171.5 27550.5 915.3

10.83 227.2 17.5 7511.9 270.9 9714.9 181.6 29410.6 917.7

15 275.3 17.6 8648.2 272.1 10854.4 216.8 31105.9 919.8

21 336.1 21.2 10509.3 298.5 12711.4 241.1 33533.0 922.3

29 486.0 22.2 12720.9 298.7 14601.4 246.6 36523.3 931.1

36 563.0 22.4 13632.7 366.8 15440.2 246.6 37640.2 935.7

45 635.8 22.7 14293.6 366.9 16451.2 274.1 38391.0 936.6

53 695.1 22.7 15039.3 368.1 17113.1 277.0 39457.0 937.4

60 749.9 22.9 15801.4 430.6 17854.1 277.1 40114.9 938.6

70 806.0 24.7 16452.6 521.9 18680.0 282.1 40368.2 939.6

80 882.3 24.7 16682.9 522.0 19535.5 302.4 40538.0 939.9

Table 4-4. Aggregate Amount of 8:2 FTOH (ng) collected by each time point

72 lass/Charge Intensity Intensity average average # of weighted weighted

relative to #ofFT- hexadecyl FT-acrylate Cw acrylate

m/z 1490 acrylate (Ci6) contribution contribution acrylate

1046.088 1.99E+03 0.18 2 0 0.369 0

1120.063 3.63E+03 0.34 2 0.337 0.673

1194 5.65E+03 0.52 0 4 0 2.096

1268.055 7.26EA-03 0.67 unidentified unidentified unidentified unidentified

1341.939 8.78E+03 0.81 2 1 1.629 0.814

1416.708 9.42E+03 0.87 1 3 0.874 2.622

1489.844 1.08E+04 1.00 0 5 0 5

1564.648 1.03E+04 0.95 3 0 2.864 0

1638.626 1.03E+04 0.95 2 2 1.909 1.909

1712.564 1.00E+04 0.93 1 4 0.928 3.711

1785.483 9.04E+03 0.84 0 6 0 5.030

1860.362 9.16E+03 0.85 3 2.548 0.849

1935.175 7.87E+03 0.73 2 1.460 2.190

2007.216 7.10E+03 0.66 1 5 0.659 3.295

2082.103 7.24E+03 0.67 0 7 0 4.701

2155.855 6.77E+03 0.63 3 2 1.885 1.257

2230.686 6.42E+03 0.60 2 4 1.191 2.382

2305.462 5.35E+03 0.50 1 6 0.496 2.979

73 2379.052 5.09E+03 0.47 0 8 0 3.775

^ 2452.066 5.10E+03 0.47 3 j 1.418 1.418

2526.037 4.60E+03 0.43 2 5 0.853 2.133

2600.735 4.36E+03 0.40 1 7 0.405 2.832

2674.712 4.06E+03 0.38 0 9 0 3.387

2748.503 3.70E+03 0.34 3 4 1.029 1.372

2822.524 3.57E+03 0.33 2 6 0.662 1.987

2896.272 3.30E+03 0.31 1 8 0.305 2.445

2969.939 3.11E+03 0.29 0 10 0 2.881

3043.887 2.83E+03 0.26 3 5 0.786 1.311

3117.85 2.68E+03 0.25 2 7 0.497 1.740

3191.464 2.51E+03 0.23 1 9 0.232 2.092

3266.854 2.27E+03 0.21 2 7.5 0.420 1.575

3340.09 2.13E+03 0.20 3 6 0.592 1.184

3414.223 2.00E+03 0.19 2 8 0.371 1.483

3488.136 1.91E+03 0.18 1 10 0.177 1.769

3563.102 1.74E+03 0.16 2 8.5 0.322 1.369

3635.612 1.64E+03 0.15 3 7 0.456 1.063

3709.74 1.61 E+03 0.15 2 9 0.299 1.345

3784.257 1.43E+03 0.13 1 11 0.132 1.456

3857.251 1.37E+03 0.13 2 9.5 0.253 1.204

3932.314 1.27E+03 0.12 3 8 0.353 0.940

74 4005.055 1.22E+03 0.11 2 10 0.226 1.129

4079.114 1.11E+03 0.10 1 12 0.103 1.230

4152.443 1.11E+03 0.10 2 10.5 0.206 1.080

4225.192 9.28E+02 0.09 3 9 0.258 0.775

4301.633 9.50E+02 0.09 2 11 0.176 0.969

4375.19 9.28E+02 0.09 1 13 0.086 1.118

4447.912 8.03E+02 0.07 2 11.5 0.149 0.857

4523.293 7.62E+02 0.07 3 10 0.212 0.707

4595.847 7.39E+02 0.07 2 12 0.137 0.824

4672.066 7.10E+02 0.07 1 14 0.065 0.922

4746 6.63E+02 0.06 2 12.5 0.123 0.770

4818.287 6.43E+02 0.06 5 7.5 0.298 0.447

4892.345 5.92E+02 0.05 4 9.5 0.220 0.522

5040.808 3.89E+02 0.04 4 10 0.144 0.360

5114.464 3.70E+02 0.03 7 5 0.240 0.172

5189.284 3.56E+02 0.03 6 7 0.198 0.231

5263.907 3.29E+02 0.03 5 9 0.153 0.274

5337.785 3.23E+02 0.03 4 11 0.120 0.330

5411.319 3.03E+02 0.03 7 6 0.197 0.168

5484.062 2.81 E+02 0.03 6 8 0.157 0.209

5557.615 2.70E+02 0.03 5 10 0.125 0.250

5632.862 2.67E+02 0.02 4 12 0.099 0.297

75 5707.955 2.40E+02 0.02 7 7 0.156 0.156

5780.44 2.46E+02 0.02 6 9 0.137 0.205

5854.833 2.12E+02 0.02 5 11 0.098 0.216

5928.467 1.97E+02 0.02 4 13 0.073 0.237

5999.737 1.95E+02 0.02 7 8 0.126 0.144

*masses >6000 had negligible impact on the calculated ratio

30.995 94.868

Ratio: 1 3.07

Table 4-5. Determination of FT-acrylate to hexadecyl acrylate Ratio of the Polymer

76 4.4 Section 2.4.1 - iyF NMR Spectroscopy Analysis

The following is the statistical analysis performed on the l9F NMR spectroscopic results investigating the degradation of FT-acrylate based polymers in pH = 4 conditions. Results of the statistical evaluation suggest that observed degradation of the polymer at pH = 4 is significant.

Group Statistics

Std. Error group N Mean Std. Deviation Mean value 1.00 6 5.5789 .15131 .06177 2.00 6 5.3283 .11695 .04774

Independent Samples Test

Levene's Test tor •quality of Variances t-test for Equality of Means 95% Confidence Interval of the Mean Std. Error Difference F Sifl. t df 3ig. (2-tailed) Difference Difference Lower Upper value Equal variance .262 .620 3.210 10 .009 .2507 .07807 .07669 .42461 assumed Equal variance 3.210 9.403 .010 .2507 .07807 .07518 .42612 not assumed

77 OVfZTX-*-

r-4

Figure 4-4. 19F NMR spectrum of hydrolysis Sample Experimental Vessel at Day 0

78 »*• zzx-

Figure 4-5. 19F NMR spectrum of hydrolysis pH = 4 Experimental Vessel at Day 80

79 0.,

o 1

o at

o i-

'3-

Figure 4-6.19F NMR spectrum of hydrolysis pH = 10 Experimental Vessel at Day 80

80 4.5 Section 2.4.1 - MALDI-ToF Analysis

Figure 4-7. MALDI Spectrum of Polymer in Sample Experimental Vessel at day 0 (I)

81 : & • o-.

r Z T— "K_

Figure 4-8. MALDI Spectrum of Polymer in pH =4 Experimental Vessel at day 80 (I)

82 E

- £2

- o -O

O -O •s

Figure 4-9. MALDI Spectrum of Polymer in pH =6 Experimental Vessel at day 80 (I)

83 E

o O oo

o o

- o — -So3

- o o to

- o - s

3 C5

Figure 4-10. MALDI Spectrum of Polymer in pH =10 Experimental Vessel at day 80 (I)

84 Figure 4-11. MALDI Spectrum of Polymer in Sample Experimental Vessel at day 0 (II)

85 Figure 4-12. MALDI Spectrum of Polymer in pH = 4 Experimental Vessel at day 80 (II)

86 Figure 4-13. MALDI Spectrum of Polymer in pH = 6 Experimental Vessel at day 80 (II)

87 88

(II) 08 ^BP *B F'lS3A pmwuiuadxa QI = Hd UI Jam^oj; jo uinjpdds IQIVPVI 'PVP 3Jtn8M 4.6 Section 2.4.1 - Hydrolytic Degradation Rates

Shown in the table below are the logarithmic trends of 8:2 FTOH evolution in experimental vessels buffered to pHs 6, 8, and 10. Logarithmic trends suggest that the polymer undergoes pseudo first-order degradation kinetics.

y= a*ln(x) + b a R value

pH = 4 -

pH = 6 3953 -928 0.9730

PH = 8 4291 40 0.9883

pH = 10 6667 13000 0.9849

Table 4-6. Degradation trends of hydrolysis experimental vessels

Shown in the table below is the statistical analysis performed in determining if the degradation rates observed did mimic pseudo first-order degradation kinetics. Calculations based on the results observed were statistically significant. y=mx+b value 95% 95% standard t-value p-value R~ value lower upper eiTor of bound bound value pH = 6 m -0.00816 -0.010 -0.006 0.001 -3.966 0.004 0.9188

b -0.09524 -0.151 -0.040 0.024 -9.512 0.000 pH = 8 m -.00909 -0.012 -0.007 0.001 -8.244 0.000 0.8946

b -0.140 -0.212 -0.069 0.031 -4.551 0.002 pH=10 m -0.067 -0.075 -0.059 0.004 -19.044 0.000 0.9787

b -0.496 -0.722 -0.270 0.098 -5.057 0.001

Table 4-7. Hydrolytic Degradation Rates of the FT polymer at various pH conditions

89 4.7 Section 2.4.2 - Wastewater Sludge Viability Test

DAY Standard Error Amount of Standard Error Amount of PFHxA 6:2 FTUCA evolution (ug)

0.5 0.076 0.001 0.0000 0.0000

4 - - 0.0000 0.0000

14 - - 0.0000 0.0000

20 0.120 0.0O3 0.0000 0.0000

27 0.131 0.003 0.0000 0.0000

33 0.122 0.015 0.0000 0.0000

34 0.355 0.039 2.2760 0.2081

35 0.530 0.032 1.4424 0.0620

40 0.614 0.027 1.4605 0.0688

48 0.726 0.039 1.0118 0.1708

55 0.728 0.032 4.1531 0.2877

57 0.966 0.050 - -

61 1.333 0.076 0.6229 0.0472

67 1.343 0.056 0.2567 0.0304

75 1.362 0.045 0.1040 5.4035e-3

88 1.413 0.048 0.0000 0.0000

105 1.502 0.090 0.0000 0.0000

131 1.611 0.057 0.0000 0.0000

153 1.566 0.074 0.0000 0.0000

Table 4-8. Viability Test - Evolution of PFHxA from 6:2 FTUCA

90 4.8 Section 2.4.2 - Headspace Analysis

Control Vessel 2 Experimental Vessel

ng 8:2 FTOH ng 8:2 FTOH DAYS collected SE collected SE

0.5 95.2 4.7 723.6 44.4

2 150.5 12.6 1293.1 84.9

4 183.8 21.1 1389.7 85.4

7 259.7 23.3 1430.8 85.5

9 293.5 24.6 1434.5 85.6

14 373.1 25.8 1434.5 85.6

20 417.3 27.6 1444.6 85.6

27 478.5 28.0 1463.2 85.6

34 602.2 29.8 1560.7 86.0

40 622.3 35.9 1560.7 86.0

47 650.4 38.7 1569.0 86.4

54 661.9 38.7 1579.8 86.4

61 676.3 39.7 1598.6 86.4

75 724.0 40.7 1626.2 86.7

89 750.0 41.0 1646.1 87.0

109 813.0 42.2 1681.4 87.0

Table 4-9. Aggregate amount of 8:2 FTOH collected in control and experimental vessels.

91 4.9 Section 2.4.2 - Aqueous Analysis

PFHxA Evolution (ng) in Experimental Vessels over time

Test Std. Con. Std. Con. Std. Con Std. Con Std. Con Std.

DAY Vessel Error 1 Error 2 Error 3 Error 4 Error 5 Error

0.5 123.7 16.0 149.7 0.0 90.7 9.3 75.7 1.0 111.4 11.1 110.7 17.0

4.0 121.6 17.4 123.6 22.3 ------85.9 11.1

9.0 111.4 11.1 120.2 2.7 ------

14.0 222.7 17.8 134.0 16.2 80.9 22.7 120.2 2.7 - - 103.4 7.1

20.0 272.2 14.5 107.9 6.7 70.7 9.5 130.9 2.7 91.6 2.3 113.0 5.3

27.0 280.5 13.1 89.5 5.1 83.0 8.9 91.3 5.0 132.2 7.4 119.0 7.8

40.0 281.0 16.1 - -

49.0 275.0 14.0 - - 99.4 16.7 109.8 12.3

61.0 280.3 19.3 - - 77.6 10.7 Converted to 145.6 9.6 75.0 277.8 12.0 - - - Viability Test . . . .

88.0 327.8 14.4 - - 81.6 4.8 98.0 0.0

105.0 378.1 19.1 99.4 16.7 - - 98.0 0.0 118.9 0.0

131.0 416.6 39.3 - - 85.1 6.7 -

153.0 425.1 26.2 - 85.1 6.7 92.7 4.6

Table 4-10. PFHxA Evolution in Experimental Vessels over time

* dash marks indicate that either measurements were not taken, or that amounts could not be determined.

92 PFHpA Evolution (ng) in Experimental Vessels over time

Test Std. Con. Std. Con. Std. Con Std. Con Std. Con Std. DAY Vessel Error 1 Error 2 Error 3 Error 4 Error 5 Error

0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

9.0 50.4 4.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

14.0 103.9 7.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

20.0 118.4 6.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

27.0 115.4 6.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

40.0 136.0 5.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

49.0 122.7 6.6 - - 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

61.0 126.5 1.3 - - 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

75.0 145.2 4.7 - - 0.0 0.0 0.0 0.0 - - 0.0 0.0

88.0 134.3 3.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

105.0 126.5 1.3 - - 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

153.0 132.3 6.9 - - 0.0 0.0 - - - - 0.0 0.0

Table 4-11. PFHpA Evolution in Experimental Vessels over time

* dash marks indicate that either measurements were not taken, or that amounts could not be determined.

93 PFOA Evolution (ng) in Experimental Vessels over time

Test Std. Con. Std. Con. Std. Con Std. Con Std. Con Std. DAY Vessel Error 1 Error 2 Error 3 Error 4 Error 5 Error

0.5 39.6 10.5 20.2 16.5 11.6 7.1 56.6 11.8 21.9 4.3 45.0 10.3

4.0 38.3 8.0 30.7 9.7 11.5 3.3

9.0 107.4 20.2 33.2 9.1 22.2 2.7

14.0 328.9 19.9 34.6 4.1 - - 12.8 9.6 32.2 4.9 35.3 6.5 20.0 362.7 14.4 51.2 2.3 23.0 6.9 12.4 7.9 17.3 4.1 42.9 8.2

27.0 370.6 10.4 20.2 16.5 9.3 8.8 - - - - 15.4 2.6

34.0 374.5 14.2 - - 40.8 10.6 9.7 5.2 - - 24.5 2.9

49.0 374.1 16.9 18.2 1.1 - - 11.0 5.2 2.6 0.1 - -

61.0 395.1 13.2 - - 23.0 6.8 39.2 5.5 11.0 5.5 - -

75.0 402.8 30.0 - - - - 17.4 2,6 - - - -

88.0 448.8 14.6 ------60.4 5.5

105.0 368.8 31.9 - - 9.3 8.8 40.0 0.0 - - - -

131.0 423.0 24.7 1.4 0.3 - - - - 32.6 0.0 28.7 0.0

153.0 431.3 66.7 - - - - 12.8 3.2 - - - -

Table 4-12. PFOA Evolution (ng) in Experimental Vessels over time

* dash marks indicate that either measurements were not taken, or that amounts could not be determined.

94 8:2 FTUCA Evolution (ng) in Experimental Vessels over time

Test Std. Con. Std. Con. Std. Con Std. Con Std. Con Std. DAY Vessel Error 1 Error 2 Error 3 Error 4 Error 5 Error

0.5 41.9 0.8 16.3 0.0 16.4 1.0 32.9 2.9 13.1 1.4 15.6 0.8

4.0 127.6 6.4 24.1 1.0 9.4 0.4 30.9 2.1 11.6 1.5 - -

9.0 69.6 1.9 22.5 5.1 2.5 1.3 26.6 2.9 7.7 2.4 - -

14.0 33.9 3.8 17.0 1.8 - - 19.5 3.0 2.6 1.9 5.4 0.6

20.0 11.8 2.9 15.2 0.2 8.1 1.4 32.2 1.4 8.0 0.6 12.5 0.4

27.0 13.2 4.2 2.2 1.2 9.2 1.2 29.0 1.4 14.4 1.5 - -

34.0 17.7 0.9 12.0 6.0 9.5 0.4 29.0 3.4 8.5 1.2 - -

40.0 11.2 1.8 2.6 1.3 - - 8.7 1.5 11.6 1.5 8.4 0.6

49.0 8.8 1.9 16.1 0.3 - - 27.0 4.7 - - - -

61.0 16.1 2.9 - - - - 38.9 4.3 8.0 0.5 19.0 0.0

75.0 1.4 0.3 - - - - 19.6 4.5 - - - -

88.0 4.2 3.3 9.1 2.3 - - 24.9 3.7 11.6 0.0 4.4 0.5

105.0 6.1 1.5 24.5 0.0 16.1 2.9 ------

131.0 13.8 1.3 - - - - 13.8 3.8 - - 9.1 2.3

153.0 7.6 3.3 - - - - 19.5 3.0 - - - -

Table 4-13.8:2 FTUCA Evolution (ng) in Experimental Vessels over time

* dash marks indicate that either measurements were not taken, or that amounts could not be determined.

95 F NMR Spectroscopy - Polymer Sorption to Sewage Sludge

0.042 Days 2.000 Days 7.000 Days

-81ppm -58ppm -81ppm -58ppm -81ppm -58ppm

88.6 11.4 87.31 12.69 85.67 14.33

88.93 11.07 87.12 12.88 85.8 14.2

88.38 11.62 87.13 12.87 85.49 14.51

88.52 11.48 87.33 12.67 85 23 14.77

88.72 11.28 87.23 12.77 85.5 14.5

88.23 11.77 87.18 12.82 85.47 14.53

88.82 11.18 87.04 12.96 85.3 14.7

88.6±0.3 11.4±0J 87.2±0.1 12.8±0.1 85.5±0.2 14.5±0.2

ratio 7.8±0.2 6.8±0.1 5.9±0.1

Table 4-14. F NMR Spectroscopy - Polymer Sorption to Sewage Sludge

96 4.10 Section 3.1 - Polymer Synthesis and Characterization

a -up

,too

o 1a ~<9 o o O •O o

(6/M) Moy je&H

Figure 4-15.DSC - Melting and Crystallization Points of newly synthesized polymer Figure 4-16. Repeating Polymeric Units in the Polymer Distribution im 330 i Na+aMtKt

butyl acrylate + butyl acrylate

vinylidene chloride + butyl acrylatt

vinylidene chloride + vinylidene chloride 11

butyl aery late

vinylidene chloride

&>iin;

• ' n lOi. i*il I • i ; \ ! „.rj^.» ! * t 8-'niiinynii|ii'n i,,,),,,,,,,,,!,,,,,.,,, u.„ „,,,„,„,„!, MI,,,,, i )•'•><" «V< •!'" •'" ,,',7""!' '•"""', •, uT• I ,iv.,p-f!~r»rr,.ji^>{ n, lyrrrr -r!,.i».|rt ^YTfr/l,lTi-i.-.i,) .1.71., "i1 V,...,.|, trr',, „,.,„„,, I.I, |M ^. ,| p, V^^?lVn^,?;frr: r>m>lf, 2M0 2&*0 ifcbO 135C SOD IV.T? 25'* :'"60 29SO 3000 rtOP 3C1C 30ol) bCtl S'CJ J 20 i'43 31a0 ;.

• ""^~

to ^ ~s IB a> i ~ Ti XI "-=_ L^ '*-> a* 'Ti a^ J^T , =5 l ~ -Q a

Figure 4-18. Determination of FT acrylate polymer signals (2)

100