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Light Scattering Size Exclusion Chromatography And Asymmetric Flow Field Flow Fractionation

Author: Stepan Podzimek
Publisher: John Wiley & Sons
ISBN: 111810272X
Size: 17.24 MB
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A comprehensive, practical approach to three powerful methods of polymer analysis and characterization This book serves as a complete compendium of three important methods widely used for the characterization of synthetic and natural polymers—light scattering, size exclusion chromatography (SEC), and asymmetric flow field flow fractionation (A4F). Featuring numerous up-to-date examples of experimental results obtained by light scattering, SEC, and A4F measurements, Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation takes an all-in-one approach to deliver a complete and thorough explanation of the principles, theories, and instrumentation needed to characterize polymers from the viewpoint of their molar mass distribution, size, branching, and aggregation. This comprehensive resource: Is the only book gathering light scattering, size exclusion chromatography, and asymmetric flow field flow fractionation into a single text Systematically compares results of size exclusion chromatography with results of asymmetric flow field flow fractionation, and how these two methods complement each other Provides in-depth guidelines for reproducible and correct determination of molar mass and molecular size of polymers using SEC or A4F coupled with a multi-angle light scattering detector Offers a detailed overview of the methodology, detection, and characterization of polymer branching Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation should be of great interest to all those engaged in the polymer analysis and characterization in industrial and university research, as well as in manufacturing quality control laboratories. Both beginners and experienced can confidently rely on this volume to confirm their own understanding or to help interpret their results.

Light Scattering Size Exclusion Chromatography And Asymmetric Flow Field Flow Fractionation

Author: Stepan Podzimek
Publisher: Wiley
ISBN: 9780470386170
Size: 73.91 MB
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View: 2487
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A comprehensive, practical approach to three powerful methods of polymer analysis and characterization This book serves as a complete compendium of three important methods widely used for the characterization of synthetic and natural polymers—light scattering, size exclusion chromatography (SEC), and asymmetric flow field flow fractionation (A4F). Featuring numerous up-to-date examples of experimental results obtained by light scattering, SEC, and A4F measurements, Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation takes an all-in-one approach to deliver a complete and thorough explanation of the principles, theories, and instrumentation needed to characterize polymers from the viewpoint of their molar mass distribution, size, branching, and aggregation. This comprehensive resource: Is the only book gathering light scattering, size exclusion chromatography, and asymmetric flow field flow fractionation into a single text Systematically compares results of size exclusion chromatography with results of asymmetric flow field flow fractionation, and how these two methods complement each other Provides in-depth guidelines for reproducible and correct determination of molar mass and molecular size of polymers using SEC or A4F coupled with a multi-angle light scattering detector Offers a detailed overview of the methodology, detection, and characterization of polymer branching Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation should be of great interest to all those engaged in the polymer analysis and characterization in industrial and university research, as well as in manufacturing quality control laboratories. Both beginners and experienced can confidently rely on this volume to confirm their own understanding or to help interpret their results.

Light Scattering Size Exclusion Chromatography And Asymmetric Flow Field Flow Fractionation

Author: Stepan Podzimek
Publisher: John Wiley & Sons
ISBN: 0470877960
Size: 23.90 MB
Format: PDF, Docs
View: 3027
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A comprehensive, practical approach to three powerful methods of polymer analysis and characterization This book serves as a complete compendium of three important methods widely used for the characterization of synthetic and natural polymers—light scattering, size exclusion chromatography (SEC), and asymmetric flow field flow fractionation (A4F). Featuring numerous up-to-date examples of experimental results obtained by light scattering, SEC, and A4F measurements, Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation takes an all-in-one approach to deliver a complete and thorough explanation of the principles, theories, and instrumentation needed to characterize polymers from the viewpoint of their molar mass distribution, size, branching, and aggregation. This comprehensive resource: Is the only book gathering light scattering, size exclusion chromatography, and asymmetric flow field flow fractionation into a single text Systematically compares results of size exclusion chromatography with results of asymmetric flow field flow fractionation, and how these two methods complement each other Provides in-depth guidelines for reproducible and correct determination of molar mass and molecular size of polymers using SEC or A4F coupled with a multi-angle light scattering detector Offers a detailed overview of the methodology, detection, and characterization of polymer branching Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation should be of great interest to all those engaged in the polymer analysis and characterization in industrial and university research, as well as in manufacturing quality control laboratories. Both beginners and experienced can confidently rely on this volume to confirm their own understanding or to help interpret their results.

Handbook Of Industrial Polyethylene And Technology

Author: Mark A. Spalding
Publisher: John Wiley & Sons
ISBN: 1119159776
Size: 16.82 MB
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This handbook provides an exhaustive description of polyethylene. The 50+ chapters are written by some of the most experienced and prominent authors in the field, providing a truly unique view of polyethylene. The book starts with a historical discussion on how low density polyethylene was discovered and how it provided unique opportunities in the early days. New catalysts are presented and show how they created an expansion in available products including linear low density polyethylene, high density polyethylene, copolymers, and polyethylene produced from metallocene catalysts. With these different catalysts systems a wide range of structures are possible with an equally wide range of physical properties. Numerous types of additives are presented that include additives for the protection of the resin from the environment and processing, fillers, processing aids, anti-fogging agents, pigments, and flame retardants. Common processing methods including extrusion, blown film, cast film, injection molding, and thermoforming are presented along with some of the more specialized processing techniques such as rotational molding, fiber processing, pipe extrusion, reactive extrusion, wire and cable, and foaming processes. The business of polyethylene including markets, world capacity, and future prospects are detailed. This handbook provides the most current and complete technology assessments and business practices for polyethylene resins.

From Linear To Long Chain Branched Poly Ethylene Terephthalate Reactive Extrusion Rheology And Molecular Characterization

Author: Kruse, Matthias
Publisher: Universitätsverlag der TU Berlin
ISBN: 3798328919
Size: 47.63 MB
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Poly(ethylene terephthalate) is one of the most widely used polymers in packaging industry, due to its high mechanical strength, chemical resistance, and barrier functions. However, its processing is determined by degradation and low viscosity. In particular, foaming and film blowing is restricted by the linear structure of the molecule and low melt strength. The stability of three linear commercial PET grades produced by different synthesis routes with different molar masses is analyzed in regards of processing at industrial scale. Subsequently, reactive processing with three multi-functional chain extenders (pyromellitic dianhydride, PMDA, tetraglycidyl diamino diphenyl methane, TGDDM, and triphenyl phosphite, TPP) is conducted to create large and long-chain branched (LCB) molecules. The mechanical and molecular properties in melt state are analyzed by linear and non-linear viscoelastic rheology, modeling by the molecular stress function (MSF) theory and size-exclusion chromatography (SEC) with light scattering measurements. Thermal stability measurements in the linear viscoelastic regime revealed degradation and a reduction of the storage modulus in air atmosphere, and, besides thermal degradation, an enhancement of the modulus in nitrogen atmosphere, due to polycondensation [Kruse et al., 2013]. Fitting by an exponential function leads to the reconstruction of the initial state of the sample at zero-loading time and to a time constant, which reveals clear relations between stability and molar mass for all three PET grades in both atmospheres. High molar mass PET is more stable in nitrogen and less stable in air environment, and vice versa, depending on OH end group concentration and synthesis route. The analysis by means of time-resolved mechanical spectroscopy allows the observations of moduli and complex viscosity at a fixed time, a wide range of angular frequencies, and at different atmospheres, and revealed: (i) a plasticizer effect induced by small molecules from thermal and thermo-oxidative degradation, (ii) cross-linking leading to yield stress, (iii) diffusion influencing polycondensation reaction, (iv) slipping due to deposition of side products, and (v) an enhanced shear thinning regime [Kruse and Wagner, 2016]. The extrusion of neat PET with a twin-screw extruder at industrial scale leads to strong reduction of viscosity mainly due to shearing. The impact of thermo-oxidative degradation is comparably small. The reactive processing of the three PET grades with the three chain extenders leads to the conclusion that the tri-functional TPP is not a useful chain extender due to rapid degradation and toxicity. The two tetra-functional chain extenders, PMDA and the epoxy-based TGDDM, lead to strong viscosity increase, increasing strain hardening effect, and increasing thermal stability with increasing chain extender concentration as confirmed by loss- and storage modulus, phase angle, activation energy of flow, and elongational viscosity. The MSF model predictions show good agreement with data measured, and allowed a quantitative analysis of the branching structure and of the stretch of the molecules by both non-linear MSF parameters. In comparison to the high molar mass PET with an apparent comb-like structure at high PMDA concentrations, the two initially low molar mass grades show a higher molar mass after processing with PMDA and seem to have a tree-like structure, which can be explained by the hydroxyl end group concentration of these two PET grades. The extensive use of TGDDM leads to a hyperbranched and gel-like structure. The fracture analysis from uniaxial elongation experiments reveals a limiting stress value for high PMDA concentrations and a limiting strain value for high TGDDM concentrations due to formation of a covalent network. The molecular analysis by SEC with triple detection of the high molar mass PET, which was reacted with PMDA and TGDDM, shows a strong increase of the average molar masses, polydispersity, radius of gyration, and hydrodynamic radius and confirms the molar mass increase observed by the rheological measurements. The branching was confirmed by a decreasing Mark-Houwink exponent with increasing chain extender concentration. Further, the analysis of the contraction of the molecule revealed a more star-like structure at low concentrations for both chain extenders. With increasing concentration, the structure changed to more comb-like for PMDA and random tree-like or hyperbranched for TGDDM as was also observed by non-linear viscoelastic measurements. PMDA revealed to be an excellent coupling agent which induces reproducibly either a star-like, comb-like, or tree-like structures depending on the concentration of coupling agent added and the hydroxyl concentration of the PET employed. Polyethylenterephthalat (PET) zeichnet sich durch hervorragende mechanische Eigenschaften, sowie chemische Beständigkeit und Barriereeigenschaften aus und findet insbesondere in der Verpackungsindustrie Verwendung. Die Neigung zur Degradation und die wegen der linearen Kettenmoleküle geringe Viskosität schränken jedoch die Verarbeitbarkeit von PET wie beispielsweise das Schäumen und Folienblasen erheblich ein. In der vorliegenden Arbeit wird der Einfluss der thermischen Stabilität während der Verarbeitung von drei linearen industriellen PET-Typen untersucht, die sich durch Molmasse und Herstellungsverfahren unterscheiden. Des Weiteren wird langkettenverzweigtes PET (LCBPET) durch reaktive Verarbeitung mit drei verschiedenen multifunktionalen Kettenverlängerern, Pyromellitsäuredianhydrid (PMDA), Tetra- glycidyl-Diamino-Diphenyl-Methan (TGDDM) und Triphenylphosphit (TPP), hergestellt und charakterisiert. Durch die experimentelle Bestimmung der linearen und nichtlinearen rheologischen Eigenschaften der Schmelze und ihre Beschreibung mit Hilfe des sogenannten "Molecular Stress Function" (MSF) Modells gelingt eine quantitative Analyse des Materialverhaltens. Die molekulare Analyse wird zusätzlich durch die Ergebnisse von Gelpermeationschromatographie (GPC bzw. SEC) in Verbindung mit Lichtstreumessung gestützt. Die Untersuchungen der thermischen Stabilität von linearem PET im linear-viskoelastischen Bereich zeigen einen abnehmenden Speichermodul und somit ein thermo-oxidatives Degradationsverhalten in Luftatmosphäre. In inerter Stickstoffatmosphäre tritt hingegen nur thermische Degradation auf, gleichzeitig führt jedoch eine Polykondensationsreaktion zu einem Anstiegen des Moduls [Kruse et al., 2013]. Mit einem exponentiellen Regressionsansatz kann der anfängliche Zustand des Moduls in beiden Atmosphären zum Zeitpunkt Null, der dem Einbringen der Probe in das Rheometer entspricht, rekonstruiert werden. Die sich aus diesem Ansatz ergebende Zeitkonstante erlaubt es, quantitative Zusammenhänge zwischen der thermischen Stabilität der drei PET-Sorten und deren Molmasse sowie dem Herstellungsverfahren der PET-Typen aufzuzeigen. So weist hochmolekulares PET eine höhere Stabilität in Stickstoff und eine geringere Stabilität in Luft auf und umgekehrt. Hauptursache für dieses Verhalten ist die unterschiedliche Konzentration an Hydroxylendgruppen, die je nach Molmasse und Herstellungsmethode der jeweiligen PET-Typen variiert. Mit Hilfe der "Time-Resolved Mechnical Sprectroscopy" konnte die sich ändernde Viskosität über ein weites Frequenzspektrum und zu einer beliebigen Messzeit in beiden Atmosphären bestimmt werden. Wesentliche Ergebnisse dieser Untersuchung sind der Nachweis des Auftretens von (i) einem Weichmachereffekt bedingt durch die thermische und thermo-oxidative Degradation und den daraus resultierenden Oligomeren, (ii) dreidimensionaler Vernetzung mit der Ausbildung einer Fließgrenze, (iii) Diffusionsprozessen, die Einfluss auf die Polykondensationsreaktion haben, (iv) Wandgleiten, bedingt durch die Ablagerung von Nebenprodukten auf den Platten des Rheometers und (v) einem verbreiterten Scherverdünnungbereich [Kruse and Wagner, 2016]. Die Extrusion von linearem PET mit einem Doppelschneckenextruder unter industriellen Bedingungen führt zu einer starken Abnahme der Viskosität, die hauptsächlich durch Scherung und weniger durch thermo-oxidativen Abbau verursacht wird. Bei der reaktiven Verarbeitung der drei PET-Typen mit den drei verschiedenen Kettenverlängerern erwies sich das dreifunktionale TPP auf Grund von Toxizität und Lagerinstabilitäten als unbrauchbar. Die Verarbeitung der beiden vierfunktionalen Kettenverlängerer, PMDA und das epoxidhaltige TGDDM, führt zu erhöhter Viskosität, erhöhter Dehnverfestigung und erhöhter thermischer Stabilität mit zunehmender Konzentration des jeweiligen Kettenverlängerers. Das beschriebene Verhalten zeigt sich sowohl am Speicher- und Verlustmodul und dem daraus abgeleiteten Verlustwinkel, als auch an der Fließaktivierungsenergie und der Dehnviskosität. Dabei lassen sich die gemessenen Dehnviskositäten sehr präzise mit dem MSF-Modell beschreiben und die beiden nichtlinearen Modelparameter, β und f_max^2 ermöglichen eine quantitative Analyse der Verzweigungsstruktur und der Molekülstreckung. So zeigt die Modifiziereng von hohen PMDA-Konzentrationen und dem hochmolekularen PET eine mehr kammartige Struktur im Vergleich zu den beiden niedermolekularen PET-Typen, die eine baumartige Molekülstruktur und eine höhere Molmasse nach der reaktiven Extrusion aufweisen. Beide Effekte können mit der höheren OH-Endgruppenkonzentration der beiden niedermolekularen PET-Typen erklärt werden. Zu hohe Zusätze von TGDDM führen zu einem hochverzweigten und gelartigen Polymer. Das Bruchverhalten bei der uniaxialen Dehnung von mit einem hohen Zusatz von PMDA hergestellten langkettenverzweigten PET wird von einer limitierenden Bruchspannung bestimmt. Demgegenüber bestimmt eine maximale Dehnung das Bruchverhalten des mit einem hohen TGDDM-Zusatz hergestellten LCB-PET, verursacht durch ein kovalent gebundenes Polymernetzwerk. Die GPC Messungen mit drei Detektoren wurden an LCB-PET durchgeführt, das auf Basis der hochmolekularen PET-Type hergestellt wurde. Die molekulare Analyse der mit PMDA und TGDDM modifizierten Proben zeigt eine deutliche Zunahme der mittleren Molmassen, Molmassenverteilungsbreite, des Gyrationsradius und des hydrodynamischen Radius und bestätigt somit die rheologischen Ergebnisse. Das Auftreten von Verzweigungen wird außerdem durch den abnehmenden Mark-Houwink-Exponenten bei zunehmender Additivkonzentration verdeutlicht. Eine genauere Betrachtung weist auf eine sternartige Molekülstruktur bei geringer Zugabe beider Kettenverlängerer hin. Bei erhöhter Zugabe hingegen tritt eine kammartige Struktur bei PMDA und eine baumartige oder hochverzweigte Struktur bei TGDDM auf, wie auch aus den nichtlinearen viskoelastischen Messungen zu schließen ist. Insbesondere PMDA erweist sich als hervorragender Kettenverlängerer, der bei reaktiver Extrusion reproduzierbar eine sternartige, kammartige oder baumartige Molekülstruktur in Abhängigkeit von der verwendeten PET-Type und der PMDA-Konzentration ermöglicht und so das Verarbeitungsspektrum von PET auf neue Anwendungsgebiete erweitert.

Advanced Separation Techniques For Polyolefins

Author: Harald Pasch
Publisher: Springer
ISBN: 3319086324
Size: 70.20 MB
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This Springer Laboratory volume introduces the reader to advanced techniques for the separation and fractionation of polyolefins. It includes detailed information on experimental protocols and procedures, addressing the experimental background of different polyolefin fractionation techniques in great detail. The book summarizes important applications in all major fractionation methods with emphasis on multidimensional analytical approaches. It comprises the most powerful modern techniques, such as high temperature size exclusion chromatography (HT-SEC) for molar mass analysis, temperature rising elution fractionation (TREF) and crystallization analysis fractionation (CRYSTAF) for the analysis of chemical composition and branching, high temperature two-dimensional liquid chromatography (HT-2D-LC), solvent and temperature gradient interaction chromatography (SGIC and TGIC) and crystallization elution fractionation (CEF). Beginners as well as experienced chromatographers will benefit from this concise introduction to a great variety in instrumentation, separation procedures and applications. With detailed descriptions of experimental approaches for the analysis of complex polyolefins, the readers are offered a toolbox to solve simple as well as sophisticated separation tasks. The book starts with an introduction into the molecular complexity of polyolefins - the most widely used synthetic polymers with rapidly growing production capacities. It systematically discusses crystallization based fractionation techniques including TREF, CRYSTAF and CEF and column chromatographic techniques for molar mass, chemical composition and microstructure, as well as the combination of different fractionations in multidimensional experimental setups. This book also includes basic information on the application of high-temperature field-flow fractionation.

Analysis Of Aggregates And Particles In Protein Pharmaceuticals

Author: Hanns-Christian Mahler
Publisher: John Wiley & Sons
ISBN: 1118150562
Size: 61.11 MB
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This book describes how to address the analysis of aggregates and particles in protein pharmaceuticals, provides a comprehensive overview of current methods and integrated approaches used to quantify and characterize aggregates and particles, and discusses regulatory requirements. Analytical methods covered in the book include separation, light scattering, microscopy, and spectroscopy.

Field Flow Fractionation In Biopolymer Analysis

Author: S. Kim R. Williams
Publisher: Springer Science & Business Media
ISBN: 3709101549
Size: 68.13 MB
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This is a timely collection of important biomedical applications for a set of separation/characterization techniques that are rapidly gaining popularity due to their wide dynamic range, high resolution, and ability to function in most commonly used solvent systems. Importantly, the field-flow fractionation (FFF) technique has recently emerged as a prominent complement to size exclusion chromatography for protein pharmaceuticals. Fractionation with FFF is gentle and preserves protein structural integrity better than existing alternatives. In the present text, different chapters are written by experts in their respective field of application, who offer comparisons between the FFF techniques and other methods for characterizing their special focus material. Practical guide-lines for successful implementation, such as choice of operating conditions, are offered in conjunction with each application. In addition to new instrumentation and approaches that address important current topics, readers are provided with an overall sense of prior (but timeless) major developments that may be overlooked in literature searches.

Aqueous Size Exclusion Chromatography

Author: P.L. Dubin
Publisher: Elsevier
ISBN: 9780080858449
Size: 36.88 MB
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The rapid development of new packings for aqueous size-exclusion chromatography has revolutionized this field. High resolution non-adsorptive columns now make possible the efficient separation of proteins and the rapid and precise determination of the molecular weight distribution of synthetic polymers. This technology is also being applied to the separation of small ions, the characterization of associating systems, and the measurement of branching. At the same time, fundamental studies are elucidating the mechanisms of the various chromatographicprocesses. These developments in principles and applications are assembled for the first time in this book. Fundamental issues are dealt with: the roles of pore structure and macromolecular dimensions, hydrophobic and electrostatic effects, and the determination and control of column efficiency. High-performance packings based on derivatized silica are reviewed in detail. Special techniques are thoroughly described, including SEC/LALLS, inverse exclusion chromatography, and frontal zone chromatography. Attention is focussed on special applications of size-exclusion methods, such as the characterization of micelles, separations of inorganic ions, and Hummel-Dreyer and related methods for equilibrium systems. Protein chromatography is dealt with in both dedicated sections and throughout the book as a whole. This is a particularly comprehensive and authoritative work - all the contributions review broad topics of general significance and the authors are of high repute. The material will be of special value for the characterization of synthetic water-soluble polymers, especially polyelectrolytes. Biochemists will find fundamental and practical guidance on protein separations. Researchers confronted with solutes that exhibit complex chromatographic behavior, such as humic acids, aggregating proteins, and micelles should find the contents of this volume illuminating.

Field Flow Fractionation Handbook

Author: Martin E. Schimpf
Publisher: John Wiley & Sons
ISBN: 9780471184300
Size: 25.48 MB
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Field flow fractionation (FFF) is an emerging separation technique, which has been proven successful in the analysis of pharmaceuticals, biotechnology products, polymers, soils, and foods, among others. In this book, Martin Schimpf joins forces with Karin Caldwell and J. Calvin Giddings, two of the primary developers of this technique, to bring you the first comprehensive, one-stop reference on the technique.