DOCSLIB.ORG

Basics of GPC (SEC) Separation Including Calibration Options

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Basics of GPC (SEC) Separation Including Calibration Options FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Basics of GPC (SEC) separation including calibration options Dr. Harry J.A. Philipsen Workshop at the International Symposium on GPC/ SEC and related techniques Amsterdam, September 26, 2016 FOR INTERNAL USE ONLY Some words on myself.. - 2016-now: Senior Scientist/ Project Director and Competence Lead Molecular Structures and Quantification of Synthetic Polymers. - 2011-2016: Resources manager Polymers Cluster at DSM Resolve, Geleen. - 2014-now: Project director “(Bio)Macromolecular Characterization” – part of the DSM corporate Analysis & Characterization program. - 2009-2012: Visiting scientist capacity group Polymer Chemistry (SPC) at TU/e and lecturer Analytical Chemistry at TU/e. - 2007-2010: New Business Development Manager at DSM Resolve, Geleen. - Until 2007: Researcher/ group leader (analytical chemist) at Océ Technologies, Venlo. -1997-now: Chairman Discussion group Separation methods of Polymers (DSP) of KNCV. - 2002-now: Board member and chairman Section Analytical Chemistry (SAC) of KNCV. - 1998: PhD Analytical Chemistry (polymer characterization), TU/e. Page 1 1 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY SEC in industrial applications - 2016 o Big gap between academic research and industrial practice on polymer separations. o SEC: one of the most used techniques for polymer characterization in industry. o Considered as simple, but still many pitfalls. o Real life accuracy and precision often cumbersome.. Page 2 FOR INTERNAL USE ONLY What is GPC/ SEC? GPC and SEC are different names for the same technique; • GPC: Gel Permeation Chromatography. • SEC: Size Exclusion Chromatography: the official IUPAC name. • Liquid chromatography technique that separates molecules according to their size (but only when performed properly). • Used for: o Separation and quantification, like in other LC-modes. o Sample prep (separation of high molecular mass substances from low molecular mass molecules of interest). o MAIN APPLICATION: determination of molar mass averages and molar mass-distribution of polymers/ macro molecules. Page 3 2 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Dispersity of polymers • Synthetic polymers and some natural polymers (e.g. starch) are polydisperse. • Types of distributions o Molecular Mass Distribution (MMD). o Branching distribution. o Chemical Composition Distribution (CCD). o Functional Type Distribution (FTD). o Charge Density Distribution (CDD). o Intrinsic Viscosity Distribution (IVD). Page 4 FOR INTERNAL USE ONLY Molar mass distribution A polymers’ molar mass and its distribution determine to a large extent final (mechanical) properties. • Various methods to assess molar mass averages and molar mass distributions. • Different statistical averages correlate to different properties: o Mn: brittleness. o Mw: processing. o Mz: elasticity. Page 5 3 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Methods for molar mass determination Various methods to assess molar mass averages and – distributions. Distributions can ONLY be determined by separation based methods. Most applied Page 6 FOR INTERNAL USE ONLY Principle of Size Exclusion Chromatography • Passadiluted (!) polymer solution over a porous gel (packed in a column) with a chosen pore size/ distribution. • Pore volume that can be accessed by small molecules is larger than that of larger molecules. Small molecules are more retained. • If this process is not influenced by enthalpic (adsorptive) interactions then elution volume can be correlated to molar mass. Therefore: (ΔH = 0) should be met. Else you will end up with mess! Page 7 4 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Scheme for SEC (or HPLC) • In essence SEC and HPLC only differ in their thermodynamic conditions. In SEC these are chosen such that no enthalpic interactions with the stationary phase occur (ΔH = 0). • Solvents: in SEC only 1 solvent is used (‘isocratic analysis’); in interactive forms of HPLC solvent programming is used (‘gradient elution’). • Often more than 1 detector is used. In SEC: combination of refractive index (RI), UV (diode array), Differential Viscometry (DV) and light scattering (LS). In HPLC: combination of UV, Evaporative Light Scattering Detection (ELSD) and MS. Page 8 FOR INTERNAL USE ONLY Retention in chromatography Distribution coefficient: K = cs/cm K = as/am exp(– ΔG/RT) ΔG = ΔH –T ΔS Retention factor: k' = ns/nm = (cs.Vs) / (cm.Vm) k' = K (Vs/ Vm) k' = (tr -t0) / t0 Page 9 5 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Entropy of macromolecular retention in a pore The smaller molecule (left) has 4 times as many possibilities for retention as the larger molecule (right). Entropy decrease for the larger molecule is bigger than that of the smaller molecule. Page 10 FOR INTERNAL USE ONLY Separation modes in polymer chromatography ΔG = ΔH –T ΔS SEC: ΔH = 0 → ΔG = TΔS KSEC = exp(ΔS/R) 0 ≤ KSEC ≤ 1 LAC: TΔS << ΔH → ΔG ≈ ΔH KLAC = exp(– ΔH/RT) KLAC ³ 1 LCCC: ΔG≈0 LAC: Liquid Adsorption Chromatography LCCC: Liquid Chromatography under Critical Conditions Page 11 6 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Chromatography of polymers • SEC: for Molecular Mass Distribution (MMD). • Gradient LAC: for Chemical Composition Distribution (CCD). • LCCC: for Functional Type Distribution (FTD), Block Length Distribution (BLD). Page 12 FOR INTERNAL USE ONLY Calibration of SEC • Measuring retention of low polydispersity polymer standards (Pd << 1.1) with known molar masses. • From the obtained calibration curve the distribution of an unknown polymer can be transformed in a molar mass distribution with its statistical averages. Page 13 7 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Narrow standards (Refractive Index-signals) Commercially available: Mw/Mn <1.1: polystyrene, PMMA, PEO. Mw/Mn <1.2: pullulan. Mw/Mn <1.3: polyethylene. Mw/Mn >1.3: polydextran, polyacrylic acid. Page 14 FOR INTERNAL USE ONLY Nomenclature, time sliced peak output Number of molecules: Ni Number fraction: ni = Ni / SNi Weight of molecules: Wi Weight fraction: wi = Wi / SWi Ni = Wi / Mi A S ni = 1 i S wi = 1 Page 15 8 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Molar mass averages (1) Page 16 FOR INTERNAL USE ONLY Molar mass averages (2) Molar mass averages according to number or mass: Mn = S niMi Mw = S wiMi Example A: 1 chain with mass 100 M ? 1 chain with mass 10 n Example B: 1 chain with mass 100 Mw ? 10 chains with mass 10 Page 17 9 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Molar mass averages (3) Example A Example B M1 = mass chain 1 100 100 M2 = mass chain 2 10 10x10 ni = number fraction 1 ½ 1/11 n2 = number fraction 2 ½ 10/11 Mn = S niMi 55 18.2 w1 = weight fraction 1 = N1M1/SNiMi 10/11 ½ w2 = weight fraction 2 = N2M2/SNiMi 1/11 ½ Mw = S wiMi 91.8 55 z1 = z - fraction 1 = w1M1/SwiMi 100/101 10/11 z2 = z - fraction 2 = w2M1/SwiMi 1/101 1/11 Mz = S ziMi 99.1 91.8 Page 18 FOR INTERNAL USE ONLY MMD moments D= Mw/Mn Mn : Impact strength Mw : Melt viscosity Mz : Elastic properties of the melt Page 19 10 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY MMD’s with identical moments • Specific moments may be identical, distribution can differ à properties! • Important to determine distributions instead of only specific moments. Page 20 FOR INTERNAL USE ONLY Differential versus cumulative mass distribution Average Sample Id Mn Mw Mz • Final result of SEC: molar Polyquat-a 6.400 9.700 13.900 Polyquat-b 7.500 11.800 17.100 Polyquat-c 8.400 13.200 18.800 mass moments PLUS molar mass distribution! Overlay Plot: WF / dLog MW Vs. Log Molecular Weigh t Method: pmm aconv-000 4.vcm 1,35 quat-a -2_0 3-02 -200 9_01.vdt : pmm aconv-00 04.vcm quat-b -2_0 3-02 -200 9_01.vdt : pmm aconv-00 04.vcm quat-c-2 _03-02-2 009_01 .vdt : pmmaconv-0004.vcm 1,20 m c 1,10 v . 4 0 0 0 - 1,00 v n o c a 0,90 Differential distribution (upper m • m p : 0,80 d o h t e 0,70 M / t d v picture) mostly used. 0,60 1 0 _ 9 0 0,50 0 2 - 2 0 - 0,40 3 0 _ 2 - 0,30 a - t a u q 0,20 0,10 -0,00 3,0 3,1 3,2 3 ,3 3,4 3,5 3,6 3,7 3,8 3,9 4,0 4,1 4 ,2 4,3 4,4 4,5 4,6 4,7 4,8 L og Molecular Weight Overlay Plot: Cumulative Weight Fraction Vs. Log Molecular Weight Method: pmma conv-0004.vcm 1,00 quat-a-2_03-02-2 009_01 .vdt : pmmaconv-00 04.vcm quat-b-2_03-02-2 009_01 .vdt : pmmaconv-00 04.vcm 0,90 quat-c-2_0 3-02-2009_ 01.vdt : pm maconv-0004.vcm m c v . 0,80 4 0 0 0 - v n 0,70 o c a m m p : 0,60 d o h t e M / 0,50 t d v . 1 0 _ 0,40 9 0 0 2 - 2 0 - 0,30 3 0 _ 2 - a - t 0,20 a u q 0,10 0,00 3,0 3 ,1 3 ,2 3,3 3,4 3,5 3,6 3,7 3 ,8 3,9 4 ,0 4 ,1 4,2 4,3 4,4 4,5 4,6 4,7 4,8 Log Molecular Weight Page 21 11 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Optimizing resolution for a wider molar mass range Ksec = (VR –V0) / Vt –V0 → VR= V0 + Ksec Vi 0 ≤ K ≤ 1 in which: Vi = Vt –V0 SEC Page 22 FOR INTERNAL USE ONLY Resolution concept in SEC of Polymers Rsp = 0.58/sD2 • Rsp: Resolution in SEC • D2: slope of calibration curve – determined by pore size distribution and pore volume • Limiting value D2 ~ 1/ (3xpore volume) Page 23 12 FOR INTERNAL USE ONLY 9/20/2016 FOR INTERNAL USE ONLY Optimizing resolution: column combinations • For optimizing resolution for a specific molar mass range of interest: we need an appropriate pore size (combination).
Load more

Recommended publications
  • POLYMER STRUCTURE and CHARACTERIZATION Professor
    POLYMER STRUCTURE AND CHARACTERIZATION Professor John A. Nairn Fall 2007 TABLE OF CONTENTS 1 INTRODUCTION 1 1.1 Definitions of Terms . 2 1.2 Course Goals . 5 2 POLYMER MOLECULAR WEIGHT 7 2.1 Introduction . 7 2.2 Number Average Molecular Weight . 9 2.3 Weight Average Molecular Weight . 10 2.4 Other Average Molecular Weights . 10 2.5 A Distribution of Molecular Weights . 11 2.6 Most Probable Molecular Weight Distribution . 12 3 MOLECULAR CONFORMATIONS 21 3.1 Introduction . 21 3.2 Nomenclature . 23 3.3 Property Calculation . 25 3.4 Freely-Jointed Chain . 27 3.4.1 Freely-Jointed Chain Analysis . 28 3.4.2 Comment on Freely-Jointed Chain . 34 3.5 Equivalent Freely Jointed Chain . 37 3.6 Vector Analysis of Polymer Conformations . 38 3.7 Freely-Rotating Chain . 41 3.8 Hindered Rotating Chain . 43 3.9 More Realistic Analysis . 45 3.10 Theta (Θ) Temperature . 47 3.11 Rotational Isomeric State Model . 48 4 RUBBER ELASTICITY 57 4.1 Introduction . 57 4.2 Historical Observations . 57 4.3 Thermodynamics . 60 4.4 Mechanical Properties . 62 4.5 Making Elastomers . 68 4.5.1 Diene Elastomers . 68 0 4.5.2 Nondiene Elastomers . 69 4.5.3 Thermoplastic Elastomers . 70 5 AMORPHOUS POLYMERS 73 5.1 Introduction . 73 5.2 The Glass Transition . 73 5.3 Free Volume Theory . 73 5.4 Physical Aging . 73 6 SEMICRYSTALLINE POLYMERS 75 6.1 Introduction . 75 6.2 Degree of Crystallization . 75 6.3 Structures . 75 Chapter 1 INTRODUCTION The topic of polymer structure and characterization covers molecular structure of polymer molecules, the arrangement of polymer molecules within a bulk polymer material, and techniques used to give information about structure or properties of polymers.
    [Show full text]
  • Polymers Division
    National Institute of Standards and Technology Technology Administration U.S. Department of MSEL Commerce NISTIR 6796 FY 2001 PROGRAMS September 2001 AND ACCOMPLISHMENTS POLYMERS DIVISION Advance measurement methods to characterize microstructure failure in composites This optical image is a planar array of glass fibers embedded in epoxy resin matrix deformed under tension. The arrays are used to investigate the failure initiation in fibrous composites. In the optical image, the fibers are spaced (30 to 45) mm apart and the dark regions along each fiber are cracks that extend into the surrounding polymer matrix. The light blue regions that connect the fiber breaks show high deformation shear bands that emanate from the tips of the matrix cracks. National Institute of Standards and Technology Karen H. Brown, MATERIALS Acting Director Technology SCIENCE AND Administration ENGINEERING U.S. Department of Commerce Donald L. Evans, Secretary LABORATORY T OF C EN OM M M T E R R FY 2001 PROGRAMS A C P E E D AND U N A I C T I E R D E S M ACCOMPLISHMENTS T A ATES OF POLYMERS DIVISION Eric J. Amis, Chief Bruno M. Fanconi, Deputy NISTIR 6796 September 2001 Table of Contents Executive Summary ............................................................................................................................................................. 1 Technical Highlights Mass Spectrometry of Polyethylene ......................................................................................................................... 4 Combinatorial Study of
    [Show full text]
  • Dispersity in Polymer Science
    Pure Appl. Chem., Vol. 81, No. 2, pp. 351–353, 2009. doi:10.1351/PAC-REC-08-05-02 © 2009 IUPAC INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY POLYMER DIVISION SUBCOMMITTEE ON POLYMER TERMINOLOGY* DISPERSITY IN POLYMER SCIENCE (IUPAC Recommendations 2009) Prepared by a Working Group consisting of R. G. GILBERT (AUSTRALIA), M. HESS (GERMANY), A. D. JENKINS (UK), R. G. JONES (UK), P. KRATOCHVÍL (CZECH REPUBLIC), AND R. F. T. STEPTO (UK) Prepared for publication by R. F. T. STEPTO‡ Polymer Science and Technology Group, Manchester Materials Science Centre, School of Materials, The University of Manchester, Grosvenor Street, Manchester, M1 7HS, UK *Membership of the Subcommittee on Polymer Terminology† during the preparation of this report (2003–2008) was as follows: M. Barón (Argentina, Secretary until 2003); M. Hess (Germany, Chairman to 2005, Secretary, 2006–2007); R. G. Jones (UK, Secretary 2003–2005, Chairman, from 2006); T. Kitayama (Japan, Secretary, from 2008); G. Allegra (Italy); T. Chang (Korea); C. dos Santos (Brazil); A. Fradet (France); K. Hatada (Japan); J. He (China); K.-H. Hellwich (Germany); R. C. Hiorns (France); P. Hodge (UK); K. Horie (Japan); A. D. Jenkins (UK); J.-I. Jin (Korea); J. Kahovec (Czech Republic); P. Kratochvíl (Czech Republic); P. Kubisa (Poland); I. Meisel (Germany); W. V. Metanomski (USA); V. Meille (Italy); I. Mita (Japan); G. Moad (Australia); W. Mormann (Germany); C. Ober (USA); S. Penczek (Poland); L. P. Rebelo (Portugal); M. Rinaudo (France); I. Schopov (Bulgaria); M. Schubert (USA); F. Schué (France); V. P. Shibaev (Russia); S. Słomkowski (Poland); R. F. T. Stepto (UK); D. Tabak (Brazil); J.-P.
    [Show full text]
  • Beyond GPC Light Scattering for Absolute Polymer
    J U N E 2 0 1 6 BEYOND GPC: USING LIGHT SCATTERING FOR ABSOLUTE POLYMER CHARACTERIZATION BEYOND GPC: USING LIGHT TOC SCATTERING FOR ABSOLUTE Table of contents POLYMER CHARACTERIZation Adding MALS Detection to GPC Overcoming Fear, Uncertainty, and Doubt in GPC: The Need for an Absolute Measurement of Molar Mass 04 Mark W. Spears, Jr. Characterizing Polymer Branching Principles of Detection and Characterization of Branching in Synthetic and Natural Polymers by MALS 11 Stepan Podzimek Analyzing Polymerization Processes Light-Scattering Techniques for Analyzing Polymerization Processes An interview with Judit E. Puskas 18 SEC–MALS vs. AF4–MALS Characterization of Styrene-Butadiene Rubbers by SEC–MALS and AF4–MALS 20 Stepan Podzimek The Most Interesting Man in Light Scattering. photo: © PeteBleyer.com We Call Him Dad. Dr. Philip Wyatt is the father of Multi-Angle Light delight them with unexpectedly attentive cus- Scattering (MALS) detection. Together with his tomer service. Check. After all, we don’t just want sons, Geof and Cliff, he leads his company to to sell our instruments, we want to help you do produce the industry’s most advanced instruments great work with them. Because at Wyatt Technol- by upholding two core premises: First, build top ogy, our family extends beyond our last name to quality instruments to serve scientists. Check. Then everyone who uses our products. For essential macromolecular and nanoparticle characterization—The Solution is Light™ © 2015 Wyatt Technology. All rights reserved. All trademarks and registered trademarks are properties of their respective holders. OVERCOMING FEAR, UNCERTAINTY, AND DOubT IN GPC: THE NEED FOR AN AbSOluTE MEASUREMENT OF MOLAR MASS Mark W.
    [Show full text]
  • Polymers, Elastomers and Composites SES Offers a Full Range of R&D, Failure Analysis and Analytical Characterization Support Services
    Materials Science & Engineering: Polymers, Elastomers and Composites SES offers a full range of R&D, failure analysis and analytical characterization support services. New Facilities-New Capabilities A Full Suite of Thermal Analysis Testing The use of polymers, Instruments elastomers and The backbone of a polymer characterization laboratory composites is growing is a suite of thermal analysis testing instruments. fast. This growth is not SES has a number of research-quality TA Instruments limited to the durable testing equipment including TGA (Thermogravimetric and non-durable Analysis), DSC (Differential Scanning Calorimeter), consumer and medical DMA (Dynamic Mechanical Analysis) and FTIR (Fourier products industries, but Transform, Infrared Spectroscopy). In addition to also includes diverse the ability to fully characterize polymers, polymer industries such as composites and elastomers, SES can conduct manufacturing equipment components, industrial exposure–based aging investigations as a function products, oilfield equipment and pipeline repair, to of applied stress/strain, temperature and time. name a few. Standard exposure-based tests can include about any combination of sustained and variable stress/strain in To meet the growing demand for polymer material contact with operating fluid, explosive decompression selection, failure analysis and material compatibility and high pressure-high temperature (HPHT) aging in assessment services, SES has invested heavily corrosive media, sterilization, physical aging, ultraviolet in staffing and polymer characterization/testing weathering, and simulated life cycle testing. instruments. A new polymer materials services facility has been constructed in SES’s centrally located Ohio facility to meet the TGA (Thermogravimetric Analysis) growing demand The TGA is generally for this work. used for compositional The labs include analysis, determination a broad range of decomposition of equipment temperature and necessary to the development of evaluate the very kinetic models for complex polymer- decomposition.
    [Show full text]
  • HT-GPC for Advanced Polymer Characterization Solution Card
    HT-GPC for Advanced Polymer Characterization TechnologyLab High Temperature GPC determines the molecular Customizable reports according to the client’s weight and molecular weight distribution of needs: Mw, Mn, Mz, PDI, SCB/1000C, LCB, polymers soluble only at high temperature, such as implementing calculation models, etc. polyolefins (HDPE, PP, LDPE, LLDPE, copolymers EP, EVA and EBA. Dual detection system with RI and Viscometer which determine the copolymer concentration and its distribution (SCB), as well the molecular structure of polymers (lineal or branched chains and branching distribution, LCB). ● High-sensitive RI detector designed to measure polymer concentration and short chain branching with excellent stability. RI detector incorporates interference filters at five different wavelengths and a thermoelectrically cooled MCT detector with high sensitivity. ● The high temperature differential viscometer detector provides a measurement of intrinsic viscosity and allows the determination of molecular size GPC-IR HT and branching structure. Technology Lab has extensive equipment that allows comprehensive and accurate polymer characterization: ● Chemical characterization by RMN, Raman and FTIR ● Rheological characterization by ARES, Brookfield and Haake ● Structural characterization by GPC, TREF, CRYSTAF ● Morphological characterization by SEM Report of results and MOP-Raman HT-GPC for Advanced Polymer Characterization ● No less than 50mg of sample is needed for ● Chemically cross-linked polymers. polymer characterization by HT-GPC. ● Polymer solubility in the working range of ● Chemically uncrossed material and the HT-GPC (30oC to 220oC). soluble in TCB (trichlorobenzen) at 150 ºC. ● Carbon black must be previously eliminated by filtration from the sample. Gel permeation chromatography (GPC) is a separation technique, commonly used for polymer characterization, which allows differentiate compounds according to their molecular size.
    [Show full text]
  • GPC - Gel Permeation Chromatography Aka Size Exclusion Chromatography- SEC
    GPC - Gel Permeation Chromatography aka Size Exclusion Chromatography- SEC Wendy Gavin Biomolecular Characterization Laboratory Version 1 May 2016 1 Table of Contents 1. GPC Introduction………………………………………………………. Page 3 2. How GPC works………………………………………………………... Page 5 3. GPC Systems…………………………………………………………… Page 7 4. GPC/SEC Separations – Theory and System Considerations… Page 9 5. GPC Reports……………………………………………………………. Page 10 6. Calibrations of GPC systems………………………………………... Page 14 7. GPC preparation……………………………………………………….. Page 16 8. Alliance System………………………………………………………… Page 17 9. GPC columns…………………………………………………………… Page 18 2 1. GPC Introduction Gel permeation chromatography (GPC) is one of the most powerful and versatile analytical techniques available for understanding and predicting polymer performance. It is the most convenient technique for characterizing the complete molecular weight distribution of a polymer. Why is GPC important? GPC can determine several important parameters. These include number average molecular weight (Mn), weight average molecular weight(Mw) Z weight average molecular weight(Mz), and the most fundamental characteristic of a polymer its molecular weight distribution(PDI) These values are important, since they affect many of the characteristic physical properties of a polymer. Subtle batch-to-batch differences in these measurable values can cause significant differences in the end-use properties of a polymer. Some of these properties include: Tensile strength Adhesive strength Hardness Elastomer relaxation Adhesive tack Stress-crack resistance Brittleness Elastic modules Cure time Flex life Melt viscosity Impact strength Tear Strength Toughness Softening temperature 3 Telling good from bad Two samples of the same polymer resin can have identical tensile strengths and melt viscosities, and yet differ markedly in their ability to be fabricated into usable, durable products.
    [Show full text]
  • Tips & Tricks GPC/SEC: Product Registration and REACH
    Tips & Tricks GPC/SEC: Product Registration and REACH Daniela Held, PSS Polymer Standards Service GmbH, Mainz, Germany Molecular mass is one of the central parameters required for product registration. Compared to low molar mass substances, the molar mass determination of macromolecular products is more diffi cult because the product is a mixture of chains with different lengths and, therefore, molar masses. Gel permeation chromatography/size-exclusion chromatography (GPC/SEC) is the standard technique to separate macromolecules by size and to measure the complete molar mass distribution as well as the molar mass averages. This technique therefore provides crucial information for product registration, including REACH. (High) performance polymers comprise widely environment. Of concern, however, are varying molecular weights, structures, and unreacted monomers, oligomers, and compositions. These molecular parameters adjuvants and additives, which are added to infl uence the macroscopic properties of the improve the processability, the stability, and resulting product and are adjusted during the the quality of the fi nal product. Leaching development process. of these (potentially toxic) components can A big advantage of polymers and cause severe (health) issues. Registration macromolecules is that they can be agencies therefore require comprehensive considered as non-toxic, even when characterization with detailed molar mass produced from toxic monomers. As a result information and, for some products, also of their size and the fact that reactive extractables and leachables studies. functional groups are reacting during The molar mass of a product is polymerization, polymers are usually traditionally measured using gel permeation considered to be (bio)chemically inert and chromatography/size-exclusion Photo Credit: saicle/Shutterstock.com do not pose a threat to humans and the chromatography (GPC/SEC) and the results 2 Q&A:Q&A: HorieHorie 6 NewsNews 9 TipsTips andand TricksTricks 14 HPLCHPLC EventEvent PPreviewreview 9 16 AndersonAnderson eett aal.l.
    [Show full text]
  • Ultrasonic Dynamic Mechanical Analysis of Polymers
    Applied_Rheology_Vol_15_5.qxd 051109 13:40 Uhr Seite 326 Ultrasonic Dynamic Mechanical Analysis of Polymers Francesca Lionetto*, Francesco Montagna, Alfonso Maffezzoli Department of Innovation Engineering, University of Lecce, 73100 Lecce, Italy * Email: [email protected] Fax: x39.0832.297525 Received: 18.7.2005, Final version: 23.9.2005 Abstract: The propagation of ultrasonic waves in polymers depends on their viscoelastic behaviour and density, resulting significantly affected by phase transitions occurring with changing temperature and pressure or during chem- ical reactions. Therefore, the application of low intensity ultrasound, acting as a high frequency dynamic mechan- ical deformation applied to a polymer, can monitor the changes of viscoelastic properties associated with the glass transition, the crystallization, the physical or chemical gelation, the crosslinking. Thanks to the non-destruc- tive character (due to the very small deformation amplitude), low intensity ultrasound can be successfully used for polymer characterization. Moreover, this technique has a big potential as a sensor for on-line and in-situ monitoring of production processes for polymers or polymer matrix composites. Recently, in the laboratory of Polymeric Materials of Lecce University a custom made ultrasonic set-up for the characterization of polymeric material, even at high temperatures, has been developed. The ultrasonic equipment is coupled with a rotation- al rheometer. Ultrasonic waves and shear oscillations at low frequency can be applied simultaneously on the sample, getting information on its viscoelastic behaviour over a wide frequency range. The aim of this paper is to present the potential and reliability of the ultrasonic equipment for the ultrasonic dynamic mechanical analy- sis (UDMA) of both thermosetting and thermoplastic polymers.
    [Show full text]
  • Polymer Analysis Chapter 1
    Polymer Analysis Chapter 1. Introduction/Overview The focus of this course is analysis and characterization of polymers and plastics. Analysis of polymeric systems is essentially a subtopic of the field of chemical analysis of organic materials. Because of this, spectroscopic techniques commonly used by organic chemists are at the heart of Polymer Analysis, e.g. infra-red (IR) spectroscopy, Raman spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and to some extent ultra-violet/visible (UV/Vis) spectroscopy. In addition, since most polymeric materials are used in the solid state, traditional characterization techniques aimed at the solid state are often encountered, x-ray diffraction, optical and electron microscopy as well as thermal analysis. Unique to polymeric materials are analytic techniques which focus on viscoelastic properties, specifically, dynamic mechanical testing. Additionally, techniques aimed at determination of colloidal scale structure such as chain structure and molecular weight for high molecular weight materials are somewhat unique to polymeric materials, i.e. gel permeation chromatography, small angle scattering (SAS) and various other techniques for the determination of colloidal scale structure. The textbook, Polymer Characterization covers all of these analytic techniques and can serve as a reference for a general introduction to the analysis of polymeric systems. Due to time constraints we can only cover a small number of analytic techniques important to polymers in this course and these are outlined in the syllabus. Structure/Processing/Property: Generally people resort to analytic techniques when confronted with a problem which involves understanding the relationship between properties of a processed material and the structure and chemical composition of the system.
    [Show full text]
  • Lecture Notes on Structure and Properties of Engineering Polymers
    Structure and Properties of Engineering Polymers Lecture: Microstructures in Polymers Nikolai V. Priezjev Textbook: Plastics: Materials and Processing (Third Edition), by A. Brent Young (Pearson, NJ, 2006). Microstructures in Polymers • Gas, liquid, and solid phases, crystalline vs. amorphous structure, viscosity • Thermal expansion and heat distortion temperature • Glass transition temperature, melting temperature, crystallization • Polymer degradation, aging phenomena • Molecular weight distribution, polydispersity index, degree of polymerization • Effects of molecular weight, dispersity, branching on mechanical properties • Melt index, shape (steric) effects Reading: Chapter 3 of Plastics: Materials and Processing by A. Brent Strong https://www.slideshare.net/NikolaiPriezjev Gas, Liquid and Solid Phases At room temperature Increasing density Solid or liquid? Pitch Drop Experiment Pitch (derivative of tar) at room T feels like solid and can be shattered by a hammer. But, the longest experiment shows that it flows! In 1927, Professor Parnell at UQ heated a sample of pitch and poured it into a glass funnel with a sealed stem. Three years were allowed for the pitch to settle, and in 1930 the sealed stem was cut. From that date on the pitch has slowly dripped out of the funnel, with seven drops falling between 1930 and 1988, at an average of one drop every eight years. However, the eight drop in 2000 and the ninth drop in 2014 both took about 13 years to fall. It turns out to be about 100 billion times more viscous than water! Pitch, before and after being hit with a hammer. http://smp.uq.edu.au/content/pitch-drop-experiment Liquid phases: polymer melt vs.
    [Show full text]
  • Impact of Particle Size and Polydispersity Index on the Clinical Applications of Lipidic Nanocarrier Systems
    pharmaceutics Review Impact of Particle Size and Polydispersity Index on the Clinical Applications of Lipidic Nanocarrier Systems M. Danaei, M. Dehghankhold, S. Ataei, F. Hasanzadeh Davarani, R. Javanmard, A. Dokhani, S. Khorasani and M. R. Mozafari * ID Australasian Nanoscience and Nanotechnology Initiative, 8054 Monash University LPO, Clayton, Victoria 3168, Australia; [email protected] (M.Da.); [email protected] (M.De.); [email protected] (S.A.); [email protected] (F.H.D.); [email protected] (R.J.); [email protected] (A.D.); [email protected] (S.K.) * Correspondence: [email protected]; Tel.: +61-42433-9961 Received: 14 April 2018; Accepted: 17 May 2018; Published: 18 May 2018 Abstract: Lipid-based drug delivery systems, or lipidic carriers, are being extensively employed to enhance the bioavailability of poorly-soluble drugs. They have the ability to incorporate both lipophilic and hydrophilic molecules and protecting them against degradation in vitro and in vivo. There is a number of physical attributes of lipid-based nanocarriers that determine their safety, stability, efficacy, as well as their in vitro and in vivo behaviour. These include average particle size/diameter and the polydispersity index (PDI), which is an indication of their quality with respect to the size distribution. The suitability of nanocarrier formulations for a particular route of drug administration depends on their average diameter, PDI and size stability, among other parameters. Controlling and validating these parameters are of key importance for the effective clinical applications of nanocarrier formulations. This review highlights the significance of size and PDI in the successful design, formulation and development of nanosystems for pharmaceutical, nutraceutical and other applications.
    [Show full text]