DOCSLIB.ORG

Oligomeric A2 + B3 Approach to Branched Poly(Arylene Ether Sulfone)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

“One-Pot” Oligomeric A2 + B3 Approach to Branched Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondensation

A thesis submitted in partial fulfillment of the requirements for the degree of
Master of Science

By
ANDREA M. ELSEN
B.S., Wright State University, 2007

2009
Wright State University
WRIGHT STATE UNIVERSITY
SCHOOL OF GRADUATE STUDIES

June 19, 2009
I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY
SUPERVISION BY Andrea M. Elsen ENTITLED “One-Pot” Oligomeric A2 + B3 Approach to Branched Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondenstation BE ACCEPTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science.

_________________________
Eric Fossum, Ph.D.
Thesis Director

_________________________
Kenneth Turnbull, Ph.D.
Department Chair

Committee on Final Examination

____________________________ Eric Fossum, Ph.D.

____________________________ Kenneth Turnbull, Ph.D.

____________________________ William A. Feld, Ph.D.

____________________________ Joseph F. Thomas, Jr., Ph.D. Dean, School of Graduate Studies

Abstract

Elsen, Andrea M. M.S., Department of Chemistry, Wright State University, 2009. “One-Pot” Oligomeric A2 + B3 Approach to Branched Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondensation

The synthesis of fully soluble branched poly(arylene ether)s via an oligomeric A2 + B3 system, in which the A2 oligomers are generated in situ, is presented. This approach takes advantage of the significantly higher reactivity toward nucleophilic aromatic substitution reactions, NAS, of B2, 4-Fluorophenyl sulfone, relative to B3, tris(4-Fluorophenyl) phosphine oxide. The A2 oligomers were synthesized by reaction of Bisphenol-A and B2, in the presence of the B3 unit, at temperatures between 100 and 160 °C, followed by an increase in the reaction temperature to 180 °C at which point the branching unit was

31

incorporated. The presence of branching was confirmed via P NMR spectroscopy and the thermal properties of the polymers were evaluated utitilizing TGA and DSC analyses.

iii

Table of Contents

1. Introduction…………………………………………………………………………….1
Linear polymers………………………………………………………...…2 Dendrimers………………………………………………………………...5 Branched poymers………………………………………………………...9 Poly(arylene ether sulfone)s……………………………………………..14 Current project…………………………………………………………...17
2. Experimental…………………………………………………………………………..19
Synthesis of 4,4-bis-(4-methylphenoxy)diphenyl sulfone,1b……………20 Synthesis of mono-substituted tris-(4-Fluorophenyl)phosphine oxide, 3a………...………………………………………..20
Representative procedure for model reactions…………………………...20 Representative polymerization procedure………………………………..21 General procedure for reverse precipitations……………………….…....21 Preparation of GC/MS calibration curve………………………………...22 Polymerization of A2 + B2 +B2’ monomers, linear analog………………22 Synthesis of A2 capped oligomers, 2a…………………………………...22 Synthesis of branched poly(arylene ether sulfone)s, 6g…………………23
3. Results and Discussion………………………………………………………………..24
Nucleophilic aromatic substitution………………………………………24 Reactivity determination…………………………………………………24 GC/MS calibration curve………………………………………………...26 Simulation of in situ oligomeric A2 formation…………………………..30

iv
Synthesis of branched poly(arylene ether sulfone)s……………………..33 Incorporation of B3 monomer……………………………………………38 Estimation of degree of branching, DB…………………………………..39 Thermal Analysis………………………………………………………...44 Conclusions………………………………………………………………47
4. References……………………………………………………………………………..48

v

List of Figures
I. Introduction:

Figure 1. Chain Entanglements……………………………………………………...…....1 Figure 2. Intrinsic or inherent viscosity versus Mn for a generic linear polymer……...…2 Figure 3. Young’s Modulus versus temperature plot for a generic linear polymer…........3 Figure 4. Poly(amido amine)……………………………..………………………….…...6 Figure 5. Generic scheme of a branched polymer…………...…………………………...9 Figure 6. Comparison of mechanical properties versus degree of branching for linear, dendritic and branched polymers………………………………………………………...10 Figure 7a. Comparison of linear, dendritic and branched polymer viscosity versus degree of branching……………………………………………………………………………...11 Figure 7b. Comparison of linear, dendritic and branched polymer viscosity versus Mw………………………………………………………………………………………..11

II. “One-Pot” Oligomeric A2 + B3 Polymerization of Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondensation

Figure 8. 4-Fluorophenyl sulfone, tris-(4-Fluorophenyl)phosphine oxide and bis-(4- Fluorophenyl)phenyl phosphine oxide…………………………………………………..25 Figure 9. The 300 MHz 1H NMR spectrum (CDCl3) of 1b……………………………..27 Figure 10. The 75 MHz 13C NMR (CDCl3) spectrum of 1b…………………………….28 Figure 11. The 121 MHz 31P NMR (CDCl3) spectrum of 3a mixture…………………..30

Figure 12. GPC overlay of 6b and 6b1…………………………………………………..34

Figure 13. Overlay of “one-pot” polymers, 6a-f………………………………………..35 Figure 14. Overlay of MeOH soluble, insoluble and crude polymer……………………36

vi

Figure 15. Overlay of 6d, 6f and 6g……………………………………………………..38

Figure 16. The 300 MHz 1H NMR spectrum (CDCl3) of 6c……………………………39 Figure 17. Potential B3 structural units…………………………………………………40 Figure 18. The 121 MHz 31P NMR (CDCl3) spectrum of 6d mixture…………………..41 Figure 19. Overlay of 31P NMR spectra of 6a-h………………………………………...43 Figure20 Overlay of TGA traces under N2………………………………...……………45 Figure 21. Overlay of DSC spectra for samples 6a-h…………………………………...46

vii

List of Schemes
I. Introduction:

Scheme 1. Divergent and convergent methods for synthesis of dendrimers…………....8 Scheme 2. Various syntheses of hyperbranched polymers...............................................13 Scheme 3. Generic synthesis of polysulfones…………...………………………………15 Scheme 4. Generic synthesis of the oligomeric A2 + B3 system………………………...16 Scheme 5. Synthesis of branched PAES via the oligomeric A2 + B3 system……………17

II. “One-Pot” Oligomeric A2 + B3 Polymerization of Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondensation

Scheme 6. NAS mechanism……………………………………………………………..34

Scheme 7. Synthesis of 1b……………………………………………………………….27

Scheme 8. Synthesis of phosphoryl based compounds 3a-c…………………………….29 Scheme 9. Model Reaction Scheme……………………………………………………..31

Scheme 10. Conversion of 3 to 2a as an AB2 oligomer………………………………...32

Scheme 11. Branched PAEs polymer synthesis…………………………………………33 Scheme 12. Synthesis of PAEs via “two-pot” literature method………………………..37

Scheme 13. Synthesis of 6h……………………………………………………………...37

viii

List of Tables
I. “One-Pot” Oligomeric A2 + B3 Polymerization of Poly(arylene ether sulfone)s: Reactivity Ratio Controlled Polycondensation

Table 1. Reactivity data of 4-Fluorophenyl sulfone, tris(4-Fluorophenyl)phosphine oxide and bis-(4-Fluorophenyl)phenylphosphine oxide……………………………………….26 Table 2. GC/MS data of model reactions………………………………………………..32 Table 3. Reaction conditions utilized for the preparation of branched PAEs…………...33 Table 4. Mn and PDI values of PAEs…………………………………………………...44 Table 5. Incorporation of B3 monomer………………………………………………….39 Table 6. Degree of branching values…………………………………………………….42 Table 7. TGA and DSC data for 6a-h…………………………………………………...45

ix

Acknowledgements

I would first like to thank Dr. Eric Fossum for his guidance, support and encouragement throughout my career at Wright State University as well as the faculty and staff of the Chemistry department. Also, many thanks to my husband, Nick, my parents, Jack and Donna, and to my sister, Laura. This could not have been accomplished without their endless love and support.

x

INTRODUCTION
Linear Polymers

Linear polymers are the most basic of polymers, consisting of only a simple back bone with two end groups. While linear polymers all have the same global structure, their individual structure will influence the conformation they exhibit. For example, poly (pphenylene terephthalamide) will exhibit a rigid-rod like structure.1 This means the polymer is in a defined rod-like shape and very little movement is allowed. On the other hand, polymers with a structure which has flexible bonds, as in poly(ether)s, will allow for random coil behavior, meaning there is no defined pattern within the structure of the polymer. While movement in rigid rod polymers is restricted, random coil polymers can participate in chain entanglements, where the chains become intertwined with one another or themselves (Figure 1). Specifically, these chain entanglements bestow mechanical properties to the polymer.

Figure 1. Chain Entanglements.
Intermolecular forces can also play a role in the ability of polymers to participate in chain entanglements. While the structure of the polymer may not be rigid on its own,

1when enough time is allowed, the polymer chains can align their intermolecular forces to form a crystalline material. For example, poly(ethylene terephthalate) can either be amorphous or crystalline depending on the time allotted for cooling. If cooled slowly, crystallites will form and the polymer’s amorphous material will be “tied down” by the crystalline material until the crystallites melt. In this semi-crystalline material, only the small portions between crystallites can have chain entanglements, significantly reducing the total number of chain entanglements within the polymer and therefore also changing the mechanical properties.
While many factors influence the ability of a polymer to participate in chain entanglements, the number-average molecular weight (Mn) of the polymer is the most important. The lowest Mn value a polymer can have and still participate in chain entanglements is known as the Critical Point of Entanglement (Mc). The Mc for a specific polymer can be found by plotting viscosity versus Mn (Figure 2).

Mc

Mn

Figure 2. Intrinsic or Inherent viscosity versus Mn for a generic linear polymer.
2
Below Mc, the viscosity is determined through Equation 1 where KL is a constant for low degree of polymerization and Z is the number of monomer units in the polymer backbone. Within this range the viscosity scales with Mn to the 1.0 power.

η = KLZ1.0

(1)
Above Mc the viscosity is determined through Equation 2. Again, Z is the number of monomer units in the polymer backbone, while KH represents a constant for high degree of polymerization. Also note the difference in power with which viscosity scales with Mn, changing from 1.0 to 3.4. This was derived using scaling concepts by de Gennes.1

η = KHZ3.4

(2)
An example of a mechanical property is viscoelasticity behavior, which is the ability to relieve various stresses through the capacity of these chain entanglements to adopt different conformations. The viscoelastic behavior of a polymer can be described by Young’s Modulus.

Figure 3. Young’s Modulus versus temperature plot for a generic linear polymer.
3
Young’s Modulus measures a polymer’s response to an applied stress. This is described in Equation 3 as the stress on the polymer over the strain by the polymer and is simply a way to measure the stiffness of the polymer.
E = ε/σ

(3)

For a typical amorphous or semi-crystalline polymer there are five regions within
Young’s Modulus (Figure 3). Region 1 is the Glassy Region, which is found at low temperatures where polymers exhibit high modulus. High modulus means the material is very hard and brittle. Throughout this region, movement within the polymer is restricted to vibrations and very small rotations. As the temperature is increased, the polymer goes through the Glass Transition (Tg), which is shown as region 2. At this point the polymer gains enough energy to show signs of cooperative motion in the backbone resulting in a considerable drop in the modulus of the polymer. Next, the modulus flattens as the polymer continues to warm and enters region 3, the Rubbery Plateau. Within this region the polymer exhibits elastic behavior. The material has enough energy that it may be stretched out, causing the chains to straighten. When the stress is removed, the chains relax back into entropically favorable positions. Region 4, called the Rubbery Flow Region acts similarly to region 3 when the stress is applied on a short time scale, however, if the stress is applied over long periods of time, the polymer will not be able to snap back to its original shape like it would in region three. The final region is the Liquid Flow Region. Here, at very high temperatures, the polymer has enough energy that the chains can move relatively quickly past one another allowing for a liquid-like behavior.1
While the physical properties of linear polymers are very attractive for many applications, most do have one quality that is undesirable: high viscosity. Typically, the

4viscosity of linear polymers is very high and this becomes a major problem when trying to process the polymer after synthesis. Often, the polymer must be diluted with solvent to obtain a processable material; therefore, it is sought-after to find a similar material that maintains the physical properties, but with a lower viscosity than traditional linear polymers.

Dendrimers

A second class of polymers, dendrimers, differs significantly from linear polymers. Dendrimers are unique because at every monomer unit they are perfectly branched. The structure of dendrimers consists only of dendritic units and chain ends which affords their globular, spherical shape.2 The first dendrimer, Polyamidoamine (PAMAM), was synthesized by Dow in 1986 (Figure 4).3 Dendrimers are typically prepared by either a divergent or convergent approach. As used in the synthesis to produce PAMAM, the divergent method grows the dendrimer outward by starting with a core molecule and adding a “layer” of monomer with each reaction to every functional group at the current chain ends. While this method has proven to be very successful in the production of many dendrimers including poly(amidoamines)4, polyethers5, and poly(arylamines)6 there are several downfalls with the method. For example, late in the synthesis, the number of functional groups on the dendrimer required to react with the monomer for proper generation growth is quite high.7 It becomes quite difficult to ensure that all reactions have occurred, creating an imperfect dendrimer.

5

NH2 O
H2N
NH2

  • NH2
  • H2N

NH2
O

N
HN
NH

O
NH
HN

O
NH
O

O

  • O
  • NH

N
O
N
H

N
NH
N

  • O
  • N

O
O
HN
NH

  • NH2
  • N

H
H2N
O

HN
N
O

HN

N
H2N
O

HN
NH
N

O
N
NH2
O
O

NH

O
O
O
HN

NH

N
N
N
H
N

NH
O
O
NH2

O
O
O
HN
HN
N

H
H2N
HN

N
O

  • N
  • H2N

Chain End

HN
H2N

O
HN
O

Dendritic Unit

NH2
NH2

Figure 4. Poly(amidoamine).

An alternative approach, the convergent method, was first introduced by Fréchet and Hawker in 1990.8-10 It begins with the chain ends and works inward toward the center

6of the molecule to finally attach all “dendritic wedges” to a core molecule forming the completed dendrimer. This method often requires only two reactions for each generation growth7 thus allowing for a cleaner synthesis and, potentially, a more perfect structure.8,

11, 12

Unfortunately, this method limits the number of generations for the dendrimer as the focal point of the reaction becomes sterically crowded. However, regardless of which method is used to synthesize dendrimers, it is a very tedious process as both require several steps as well as extensive purification after each generation is formed (Scheme

1).13

7

  • Divergent
  • Convergent

2x
6x

Scheme 1. Divergent and convergent methods for synthesis of dendrimers
8
Due to the dense surfaces of dendrimers, they cannot have chain entanglements with other dendritic molecules. Therefore, dendritic materials generally exhibit poor mechanical properties and engineering applications are often limited to blending agents while biological applications range from molecular delivery agents to unimolecular micelles.14 An interesting characteristic of dendrimers is their intrinsic viscosity. Unlike linear polymers, whose viscosity continues to rise with increasing molecular weight, a dendrimer’s viscosity typically goes through a maximum as the density of the surface increases and is always lower than its linear counterpart.15

Branched Polymers

Branched polymers, are a hybrid of linear and dendritic polymers, both structurally and physically. In Figure 5 a generic structure of a branched polymer is shown and it is evident that these polymers consist of linear, dendritic and teminal units.

Terminal Unit
Linear Unit

Dendritic Unit
Figure 5. Generic representation of a branched polymer

9

Branched polymers are unique because their properties are directly related to the degree of branching (DB). The degree of branching, DB is defined by the number of linear (

L

), terminal (

T

  • ), and dendritic (
  • D) units present in each polymer (Equation 5).

D + T
DB =

(5)

D + T + L

So by changing the number of branching units within the polymer the physical properties should also change. Figure 6 depicts the relationship between mechanical properties and DB. Linear polymers have no branching (DB = 0) and their mechanical properties are very good. On the other hand, dendrimers have perfect branching (DB = 1) while their mechanical properties are very poor. Branched polymers are unique in that they can be prepared with varying DB values, thus, it should be possible to tailor their mechanical properties. For example, if a highly branched polymer is made, it should exhibit more dendritic-like qualities, while a very lightly branched polymer should exhibit qualities closer to those of linear polymers.

Recommended publications
  • And Ph-Dependent Oligomerization of the Thrombin-Derived C-Terminal Peptide TCP-25

    And Ph-Dependent Oligomerization of the Thrombin-Derived C-Terminal Peptide TCP-25

    biomolecules Article Concentration- and pH-Dependent Oligomerization of the Thrombin-Derived C-Terminal Peptide TCP-25 Ganna Petruk 1,* , Jitka Petrlova 1, Firdaus Samsudin 2 , Rita Del Giudice 3 , Peter J. Bond 2,4 and Artur Schmidtchen 1,5,6 1 Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, 22241 Lund, Sweden; [email protected] (J.P.); [email protected] (A.S.) 2 Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore; [email protected] (F.S.); [email protected] (P.J.B.) 3 Research Centre for Biointerfaces, Department of Biomedical Sciences and Biofilms, Malmö University, 20506 Malmö, Sweden; [email protected] 4 Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore 5 Copenhagen Wound Healing Center, Bispebjerg Hospital, Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark 6 Dermatology, Skane University Hospital, 22185 Lund, Sweden * Correspondence: [email protected]; Tel.: +46-46-22-23-315 Received: 18 October 2020; Accepted: 9 November 2020; Published: 19 November 2020 Abstract: Peptide oligomerization dynamics affects peptide structure, activity, and pharmacodynamic properties. The thrombin C-terminal peptide, TCP-25 (GKYGFYTHVFRLKKWIQKVIDQFGE), is currently in preclinical development for improved wound healing and infection prevention. It exhibits turbidity when formulated at pH 7.4, particularly at concentrations of 0.3 mM or more. We used biochemical and biophysical approaches to explore whether the peptide self-associates and forms oligomers. The peptide showed a dose-dependent increase in turbidity as well as α-helical structure at pH 7.4, a phenomenon not observed at pH 5.0.
  • Cationic/Anionic/Living Polymerizationspolymerizations Objectives

    Cationic/Anionic/Living Polymerizationspolymerizations Objectives

    Chemical Engineering 160/260 Polymer Science and Engineering LectureLecture 1919 -- Cationic/Anionic/LivingCationic/Anionic/Living PolymerizationsPolymerizations Objectives • To compare and contrast cationic and anionic mechanisms for polymerization, with reference to free radical polymerization as the most common route to high polymer. • To emphasize the importance of stabilization of the charged reactive center on the growing chain. • To develop expressions for the average degree of polymerization and molecular weight distribution for anionic polymerization. • To introduce the concept of a “living” polymerization. • To emphasize the utility of anionic and living polymerizations in the synthesis of block copolymers. Effect of Substituents on Chain Mechanism Monomer Radical Anionic Cationic Hetero. Ethylene + - + + Propylene - - - + 1-Butene - - - + Isobutene - - + - 1,3-Butadiene + + - + Isoprene + + - + Styrene + + + + Vinyl chloride + - - + Acrylonitrile + + - + Methacrylate + + - + esters • Almost all substituents allow resonance delocalization. • Electron-withdrawing substituents lead to anionic mechanism. • Electron-donating substituents lead to cationic mechanism. Overview of Ionic Polymerization: Selectivity • Ionic polymerizations are more selective than radical processes due to strict requirements for stabilization of ionic propagating species. Cationic: limited to monomers with electron- donating groups R1 | RO- _ CH =CH- CH =C 2 2 | R2 Anionic: limited to monomers with electron- withdrawing groups O O || || _ -C≡N -C-OR -C- Overview of Ionic Chain Polymerization: Counterions • A counterion is present in both anionic and cationic polymerizations, yielding ion pairs, not free ions. Cationic:~~~C+(X-) Anionic: ~~~C-(M+) • There will be similar effects of counterion and solvent on the rate, stereochemistry, and copolymerization for both cationic and anionic polymerization. • Formation of relatively stable ions is necessary in order to have reasonable lifetimes for propagation.
  • Structural Mechanisms of Oligomer and Amyloid Fibril Formation by the Prion Protein Cite This: Chem

    Structural Mechanisms of Oligomer and Amyloid Fibril Formation by the Prion Protein Cite This: Chem

    ChemComm View Article Online FEATURE ARTICLE View Journal | View Issue Structural mechanisms of oligomer and amyloid fibril formation by the prion protein Cite this: Chem. Commun., 2018, 54,6230 Ishita Sengupta a and Jayant B. Udgaonkar *b Misfolding and aggregation of the prion protein is responsible for multiple neurodegenerative diseases. Works from several laboratories on folding of both the WT and multiple pathogenic mutant variants of the prion protein have identified several structurally dissimilar intermediates, which might be potential precursors to misfolding and aggregation. The misfolded aggregates themselves are morphologically distinct, critically dependent on the solution conditions under which they are prepared, but always b-sheet rich. Despite the lack of an atomic resolution structure of the infectious pathogenic agent in prion diseases, several low resolution models have identified the b-sheet rich core of the aggregates formed in vitro, to lie in the a2–a3 subdomain of the prion protein, albeit with local stabilities that vary Received 17th April 2018, with the type of aggregate. This feature article describes recent advances in the investigation of in vitro Accepted 14th May 2018 prion protein aggregation using multiple spectroscopic probes, with particular focus on (1) identifying DOI: 10.1039/c8cc03053g aggregation-prone conformations of the monomeric protein, (2) conditions which trigger misfolding and oligomerization, (3) the mechanism of misfolding and aggregation, and (4) the structure of the misfolded rsc.li/chemcomm intermediates and final aggregates. 1. Introduction The prion protein can exist in two distinct structural isoforms: a National Centre for Biological Sciences, Tata Institute of Fundamental Research, PrPC and PrPSc.
  • Photopolymerization Reactions Under Visible Lights: Principle, Mechanisms and Examples of Applications J.P

    Photopolymerization Reactions Under Visible Lights: Principle, Mechanisms and Examples of Applications J.P

    Progress in Organic Coatings 47 (2003) 16–36 Photopolymerization reactions under visible lights: principle, mechanisms and examples of applications J.P. Fouassier∗, X. Allonas, D. Burget Département de Photochimie Générale, UMR n◦7525, Ecole Nationale Supérieure de Chimie, 3 Rue Alfred Werner, 68093 Mulhouse Cedex, France Received 22 June 2002; received in revised form 19 November 2002; accepted 20 December 2002 Abstract A general overview of visible light photoinduced polymerization reactions is presented. Reaction mechanisms as well as practical efficiency in industrial applications are discussed. Several points are investigated in detail: photochemical reactivity of photoinitiating system (PIS), short overview of available photoinitiators (PIs) and photosensitizers (PSs), mechanisms involved in selected examples of dye sensitized polymerization reactions, examples of applications in pigmented coatings usable as paints, textile printing, glass reinforced fibers, sunlight curing of waterborne latex paints, curing of inks, laser-induced polymerization reactions, high speed photopolymers for laser imaging, PISs for computer-to-plate systems. © 2003 Elsevier Science B.V. All rights reserved. Keywords: Photopolymerization; Visible light; Radiation curing 1. Introduction Radical, cationic and anionic polymerizations can be ini- tiated by the excitation of suitable photoinitiating systems Radiation curing technologies provide a number of eco- (PISs) under lights. Most of these systems were originally nomic advantages over the usual thermal operation among sensitive to UV lights but by now a large number of various them: rapid through cure, low energy requirements, room systems allows to extend the spectral sensitivity to visible temperature treatment, non-polluting and solvent-free for- lights. According to the applications which are developed, mulations, low costs.
  • On the Mechanism of Oligomer Formation in Condensations of Alkyl Cyanoacetates with Formaldehyde

    On the Mechanism of Oligomer Formation in Condensations of Alkyl Cyanoacetates with Formaldehyde

    Polymer Journal, Vol. 13, No. 10, pp 975-978 (1981) NOTE On the Mechanism of Oligomer Formation in Condensations of Alkyl Cyanoacetates with Formaldehyde J. M. ROONEY Loctite (Ireland) Limited, Whitestown Industrial Estate, Ta//aght, Co. Dublin. Ireland. (Received December II, 1980) KEY WORDS Alkyl Cyanoacetates I Formaldehyde / Condensation Anionic Polymerization I Cyanoacrylate I Chain Transfer I Industrial synthetic routes to the production of Since the apparent activation energy of the over­ alkyl cyanoacrylate monomers frequently involve all process was found to be similar to that of the base-catalyzed condensations of alkyl cyanoacetates condensation of diethyl dicyanoglutarate with for­ with formaldehyde to form low molecular weight maldehyde, the addition of diethyl dicyanoglutarate polymers. 1 Early studies attributed polymer for­ to formaldehyde is assumed to be the rate­ mation to a stepwise condensation2 of the form,3.4 determining step. CN CN I I CH2 + HCHO _..... CHCH20H I I COOR COOR CN CN CN CN I I I I CHCH2 0H + CH2 -----. CH-CH2-CH + H2 0 I I I I COOR COOR COOR COOR CN CN CN CN I I I I CH-CH2-CH + HCHO -----. CH-CH2-C-CH20H I I I I COOR COOR COOR COOR CN CN CN I I I CH-CH2-C-CH20H + CH2 etc. I I I COOR COOR COOR Subsequently, a kinetic study of the reaction of philic displacement of the hydroxyl group by cya­ formaldehyde with methyl cyanoacetate5 yielded noacetate anion. Instead, it is postulated that evidence that methyl cyanoacrylate monomer is an essential step in water evolution is the formation of intermediate in oligomer formation.
  • Polymer Exemption Guidance Manual POLYMER EXEMPTION GUIDANCE MANUAL

    Polymer Exemption Guidance Manual POLYMER EXEMPTION GUIDANCE MANUAL

    United States Office of Pollution EPA 744-B-97-001 Environmental Protection Prevention and Toxics June 1997 Agency (7406) Polymer Exemption Guidance Manual POLYMER EXEMPTION GUIDANCE MANUAL 5/22/97 A technical manual to accompany, but not supersede the "Premanufacture Notification Exemptions; Revisions of Exemptions for Polymers; Final Rule" found at 40 CFR Part 723, (60) FR 16316-16336, published Wednesday, March 29, 1995 Environmental Protection Agency Office of Pollution Prevention and Toxics 401 M St., SW., Washington, DC 20460-0001 Copies of this document are available through the TSCA Assistance Information Service at (202) 554-1404 or by faxing requests to (202) 554-5603. TABLE OF CONTENTS LIST OF EQUATIONS............................ ii LIST OF FIGURES............................. ii LIST OF TABLES ............................. ii 1. INTRODUCTION ............................ 1 2. HISTORY............................... 2 3. DEFINITIONS............................. 3 4. ELIGIBILITY REQUIREMENTS ...................... 4 4.1. MEETING THE DEFINITION OF A POLYMER AT 40 CFR §723.250(b)... 5 4.2. SUBSTANCES EXCLUDED FROM THE EXEMPTION AT 40 CFR §723.250(d) . 7 4.2.1. EXCLUSIONS FOR CATIONIC AND POTENTIALLY CATIONIC POLYMERS ....................... 8 4.2.1.1. CATIONIC POLYMERS NOT EXCLUDED FROM EXEMPTION 8 4.2.2. EXCLUSIONS FOR ELEMENTAL CRITERIA........... 9 4.2.3. EXCLUSIONS FOR DEGRADABLE OR UNSTABLE POLYMERS .... 9 4.2.4. EXCLUSIONS BY REACTANTS................ 9 4.2.5. EXCLUSIONS FOR WATER-ABSORBING POLYMERS........ 10 4.3. CATEGORIES WHICH ARE NO LONGER EXCLUDED FROM EXEMPTION .... 10 4.4. MEETING EXEMPTION CRITERIA AT 40 CFR §723.250(e) ....... 10 4.4.1. THE (e)(1) EXEMPTION CRITERIA............. 10 4.4.1.1. LOW-CONCERN FUNCTIONAL GROUPS AND THE (e)(1) EXEMPTION.................
  • Specifications Guide Americas Petrochemicals Latest Update: July 2020

    Specifications Guide Americas Petrochemicals Latest Update: July 2020

    Specifications Guide Americas Petrochemicals Latest update: July 2020 Definitions of the trading locations for which Platts publishes daily indexes or assessments 2 Olefins 3 US aromatics 6 Latin American aromatics 8 US polymers 10 Latin American polymers 13 US intermediates 16 US hydrocarbon solvents 17 US chlor alkali 18 US oxygenated solvents 19 Liquid and gas chemical freight 21 Global petrochemical indices 22 Revision history 23 www.spglobal.com/platts Specifications Guide Americas Petrochemicals: July 2020 DEFINITIONS OF THE TRADING LOCATIONS FOR WHICH PLATTS PUBLISHES DAILY INDEXES OR ASSESSMENTS The following specifications guide contains the primary specifications for S&P Global Platts petrochemical assessments in the Americas. All the assessments listed here employ Platts Assessments Methodology, as published at https://www.spglobal.com/platts/plattscontent/_assets/_files/en/our-methodology/methodology-specifications/platts-assessments-methodology-guide.pdf. These guides are designed to give Platts subscribers as much information as possible about a wide range of methodology and specification questions. This guide is current at the time of publication. Platts may issue further updates and enhancements to this methodology and will announce these to subscribers through its usual publications of record. Such updates will be included in the next version of this guide. Platts editorial staff and managers are available to provide guidance when assessment issues require clarification. OLEFINS Assessment CURRENCY CODE Mavg Wavg TYPE
  • Guidance for Monomers and Polymers

    Guidance for Monomers and Polymers

    GUIDANCE Guidance for monomers and polymers April 2012 Version 2.0 Guidance for the implementation of REACH Annankatu 18, P.O. Box 400, FI-00121 Helsinki, Finland | Tel. +358 9 686180 | Fax +358 9 68618210 | echa.europa.eu Guidance for monomers and polymers 2 Version 2.0 April 2012 Version Changes Date Version 0 First edition June 2007 Version 1 Section 2.2 - More explanations given on the 18/03/2008 definition of polymer (including different types of additives). Most of section 3.3 transferred to here. Section 3.1 - Clarification of cases where the substance is used both as monomer and as intermediate under strictly controlled conditions. Section 3.2.1.1 - Addition of a sentence to clarify that there is no need to register stabilisers Section 3.2.1.2 - The section has been modified in order to reflect a proposal for solution for those substances already notified. Section 3.2.1.3 - Some wording change for clarification that only the substance used for the modification of the natural polymer needs to be registered when ending up chemically bound to the polymer. Section 3.2.1.4 - Need for update acknowledged. Previous Section 3.3 - Deleted and mostly transferred to section 2.2. Version 1.1 Section 3.2.1.2 - Based on the comments 27/05/2008 received from Ireland after the CA meeting in December 2007 some additional guidance on what needs to be done for notified polymers has been added (4 pages). Version 2.0 Section 2.1 and 3.1 – Reference to monomers as April 2012 intermediate reworded in order to be consistent with new clarification of intermediate definition.
  • Polymer of Acrylic Acid Oligomer, Its Preparation and Use in Coating And

    Polymer of Acrylic Acid Oligomer, Its Preparation and Use in Coating And

    Europaisches Patentamt European Patent Office © Publication number: 0 036 294 Office europeen des brevets A2 © EUROPEAN PATENT APPLICATION © Application number: 81301029.5 © int. ci 3: C 08 F 20/28 © Date of filing: 12.03.81 © Priority: 14.03.80 US 130323 © Applicant: Rohm and Haas Company Independence Mall West Philadelphia, Pennsylvania 191051US) @ Date of publication of application: 23.09.81 Bulletin 81/38 © Inventor: Merritt, Richard Foster 1811 Shelly Lane © Designated Contracting States: Fort Washington Pennsylvania 19034IUS) BE CH DE FR GB IT LI NL SE © Inventor: Larsson, Bjorn Eric Swamp Road Rushland Pennsylvania 18956(US) © Representative: Angell, David Whilton et al, Rohm and Haas Company Patent Department Chesterfield House Barter Street London WC1A2TP(GB) © Polymer of acrylic acid oligomer, its preparation and use in coating and/or impregnating compositions and the moderation of copolymer glass transition temperature using the oligomer. © Acrylic acidacid oligomeroligomer of thethe formulaformula: : 0 0 CH =CH-C-0(CH, •0) H @CH2C n where n has anan average value value (n) (n) of from greater thanthan 1 to 10 is polymerised, alone or with other ethylenicallyethylenicaliy unsaturated monomer, by emulsion or solution polymerisation. When When nn is from 2 to 10 any known polymerisation technique may be used, but emulsion or solution polymerization is preferred. The be used moderate the transition CM monomer may to glass of The polymer be used in < temperature copolymers. may coating and/or impregnating compositions such as inks, caulks, sealants, adhesives, fabric print pastes and non- Gi woven fabric binders. CM CD CO o Q. UJ Croydon Printing Company Ltd.
  • Bio-Based and Biodegradable Plastics – Facts and Figures Focus on Food Packaging in the Netherlands

    Bio-Based and Biodegradable Plastics – Facts and Figures Focus on Food Packaging in the Netherlands

    Bio-based and biodegradable plastics – Facts and Figures Focus on food packaging in the Netherlands Martien van den Oever, Karin Molenveld, Maarten van der Zee, Harriëtte Bos Rapport nr. 1722 Bio-based and biodegradable plastics - Facts and Figures Focus on food packaging in the Netherlands Martien van den Oever, Karin Molenveld, Maarten van der Zee, Harriëtte Bos Report 1722 Colophon Title Bio-based and biodegradable plastics - Facts and Figures Author(s) Martien van den Oever, Karin Molenveld, Maarten van der Zee, Harriëtte Bos Number Wageningen Food & Biobased Research number 1722 ISBN-number 978-94-6343-121-7 DOI http://dx.doi.org/10.18174/408350 Date of publication April 2017 Version Concept Confidentiality No/yes+date of expiration OPD code OPD code Approved by Christiaan Bolck Review Intern Name reviewer Christaan Bolck Sponsor RVO.nl + Dutch Ministry of Economic Affairs Client RVO.nl + Dutch Ministry of Economic Affairs Wageningen Food & Biobased Research P.O. Box 17 NL-6700 AA Wageningen Tel: +31 (0)317 480 084 E-mail: [email protected] Internet: www.wur.nl/foodandbiobased-research © Wageningen Food & Biobased Research, institute within the legal entity Stichting Wageningen Research All rights reserved. No part of this publication may be reproduced, stored in a retrieval system of any nature, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher. The publisher does not accept any liability for inaccuracies in this report. 2 © Wageningen Food & Biobased Research, institute within the legal entity Stichting Wageningen Research Preface For over 25 years Wageningen Food & Biobased Research (WFBR) is involved in research and development of bio-based materials and products.
  • Aim: to Prepare Block Copolymers of Methyl Methacrylate (MMA) and Styrene

    Aim: to Prepare Block Copolymers of Methyl Methacrylate (MMA) and Styrene

    Conducting A Reversible-Deactivation Radical Polymerization (RDRP) Aim: To Prepare Block Copolymers of Methyl Methacrylate (MMA) and Styrene. Polymers are ubiquitous in the modern world. They provide tremendous value because the chemical and physical properties of these materials are determined by the monomers that are used to put them together. One of the most powerful methods to construct polymers is radical-chain polymerization and this method is used in the commercial synthesis of polymers everyday. Methyl methacrylate is polymerized to form poly(methyl methacrylate) (PMMA) which is also known as acrylic glass or Plexiglas (about 2 billion pounds per year in the US). This material is lightweight, strong and durable. The polymer chains are rigid due to the tetrasubstituted carbon atom in the polymer backbone and they have excellent optical clarity. As a consequence, these materials are used in aircraft windows, glasses, skylights, signs and displays. Polystyrene (PS), which can also be synthesized from radical chain polymerization, has found extensive use as a material (also approximately 2 billion pounds per year in the US). One of the forms of PS, Styrofoam, is used extensively to make disposable cups, thermal insulation, and cushion for packaging. Scheme 1. Radical polymerization of methyl methacrylate or styrene. While there are extensive uses for these polymers, when synthesizing any material using a free-radical polymerization, samples are obtained with limited control over molecular weight and molecular weight distribution. New methods have been developed directly at Carnegie Mellon (https://www.cmu.edu/maty/) which lead to improved control in this process. This new method is a reversible-deactivation of the polymerization reaction where highly reactive radicals toggle back and forth between an active state, where the polymer chain is growing, and a dormant state, where the polymer chain is capped (Scheme 2).
  • Random-Sequence Genetic Oligomer Pools Display an Innate Potential For

    Random-Sequence Genetic Oligomer Pools Display an Innate Potential For

    RESEARCH ARTICLE Random-sequence genetic oligomer pools display an innate potential for ligation and recombination Hannes Mutschler1†‡*, Alexander I Taylor1†, Benjamin T Porebski1, Alice Lightowlers1§, Gillian Houlihan1, Mikhail Abramov2, Piet Herdewijn2, Philipp Holliger1* 1MRC Laboratory of Molecular Biology, Cambridge, United Kingdom; 2REGA Institute, Katholieke Universiteit Leuven, Leuven, Belgium Abstract Recombination, the exchange of information between different genetic polymer strands, is of fundamental importance in biology for genome maintenance and genetic diversification and is mediated by dedicated recombinase enzymes. Here, we describe an innate capacity for non-enzymatic recombination (and ligation) in random-sequence genetic oligomer pools. Specifically, we examine random and semi-random eicosamer (N20) pools of RNA, DNA and *For correspondence: the unnatural genetic polymers ANA (arabino-), HNA (hexitol-) and AtNA (altritol-nucleic acids). Correspondence to: ph1@mrc- While DNA, ANA and HNA pools proved inert, RNA (and to a lesser extent AtNA) pools displayed lmb.cam.ac.uk; [email protected] diverse modes of spontaneous intermolecular recombination, connecting recombination mechanistically to the vicinal ring cis-diol configuration shared by RNA and AtNA. Thus, the † These authors contributed chemical constitution that renders both susceptible to hydrolysis emerges as the fundamental equally to this work determinant of an innate capacity for recombination, which is shown to promote a concomitant Present address: