Materials Science › Polymers and Plastics

Polymer crystallization and properties

Works Count: 60400

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This cluster of papers focuses on the crystallization behavior, properties, and processing of polymers, including the influence of nanoparticles, recycling methods, and the mechanical and rheological aspects of polymer blends. It covers topics such as polymer crystallization kinetics, morphology development, conducting polymers, and the use of various techniques to characterize the properties of polymers.

Keywords

Polymer Crystallization; Polymer Blends; Nanoparticles; Recycling; Mechanical Properties; Morphology Development; Rheology; Conducting Polymers; Crystallization Kinetics; Chemical Recycling

Properties of polymers: their correlation with chemical structure; their numerical estimation and prediction from additive group contributions

1991-09-01

Van Krevelen

This authoritative, widely cited book has been used all over the world. The fourth edition incorporates the latest developments in the field while maintaining the core objectives of previous editions: … This authoritative, widely cited book has been used all over the world. The fourth edition incorporates the latest developments in the field while maintaining the core objectives of previous editions: to correlate properties with chemical structure and to describe methods that permit the estimation and prediction of numerical properties from chemical structure, i.e. nearly all properties of the solid, liquid, and dissolved states of polymers. This title extends coverage of critical topics such as electrical and magnetic properties, rheological properties of polymer melts, and environmental behavior and failure. It discusses liquid crystalline polymers across chapters 6, 15, and 16 for greater breadth and depth of coverage. It increases the number of supporting illustrations from approximately 250 (in the previous edition) to more than 400 to further aid in visual understanding.

Physical Properties of Polymers Handbook

2007-01-01

James E. Mark

Crystalline forms of isotactic polypropylene

1964-01-01

Alan Jones , Jean M. Aizlewood , D. R. Beckett

Abstract The X‐ray diffraction patterns of two crystalline forms of isotactic polypropylene, the β‐ and γ‐forms distinct from the α‐form described by NATTA 1 , have been recorded. The β‐form, … Abstract The X‐ray diffraction patterns of two crystalline forms of isotactic polypropylene, the β‐ and γ‐forms distinct from the α‐form described by NATTA 1 , have been recorded. The β‐form, previously observed only as single spherulites 6 has now been obtained in a well crystalline polymer, practically free of α‐form. The γ‐form is obtained, free of α‐form, in stereoblock fractions taken over the range 35–70°C. from normal commercial polypropylenes; the γ‐form is formed after cooling from the melt. The conditions for the production of the two forms and their melting behaviour, have been investigated by X‐rays. Oriented fibres were not obtained in either form as conversion to α‐form took place on drawing. Both forms have a ternary helical chain configuration. The derivation of the unit cells of the β‐ and γ‐forms from X‐ray photographs of unoriented specimens has been attempted and speculations have been made as to the packing of the helices in both forms. There are at least six and possibly twelve helical chains in the pseudohexagonal unit cell of the β‐form; the unit cell of the γ‐form is triclinic.

Molecular model of drawing polyethylene and polypropylene

1971-06-01

A. Peterlin

Characterization of Polystyrenes of Extremely High Molecular Weights

1980-05-01

Bernd K. Appelt , Günther Meyerhoff

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCharacterization of Polystyrenes of Extremely High Molecular WeightsBernd Appelt and Günther MeyerhoffCite this: Macromolecules 1980, 13, 3, 657–662Publication Date (Print):May 1, 1980Publication History Published online1 May 2002Published … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCharacterization of Polystyrenes of Extremely High Molecular WeightsBernd Appelt and Günther MeyerhoffCite this: Macromolecules 1980, 13, 3, 657–662Publication Date (Print):May 1, 1980Publication History Published online1 May 2002Published inissue 1 May 1980https://pubs.acs.org/doi/10.1021/ma60075a033https://doi.org/10.1021/ma60075a033research-articleACS PublicationsRequest reuse permissionsArticle Views218Altmetric-Citations910LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Kinetic of crystallization from the melt and chain folding in polyethylene fractions revisited: theory and experiment

1997-01-01

John D. Hoffman , Robert L. Miller

The rate of growth of chain-folded lamellar crystals from the subcooled melt of polyethylene fractions is treated in terms of surface nucleation theory with the objective of illuminating the origin … The rate of growth of chain-folded lamellar crystals from the subcooled melt of polyethylene fractions is treated in terms of surface nucleation theory with the objective of illuminating the origin of the chain folding phenomenon and associated kinetic effects in molecular terms. An updated version of flux-based nucleation theory in readily usable form is outlined that deals with the nature of polymer chains in more detail than previous treatments. The subjects covered include: (i) the origin of regimes I, II, III, and III-A and the associated crystal growth rates, including the effect of forced steady-state reptation and reptation of ‘slack’ in the subcooled melt; (ii) the variation of the initial lamellar thickness with undercooling; (iii) the origin of the fold surface free energy σe and the lateral surface free energy σ; (iv) the generation and effect of nonadjacent events (such as tie chains) on the crystallinity and growth rates; and (v) ‘quantized’ chain folding at low molecular weight. The topological limitation on nonadjacent re-entry and the value of the apportionment factor ψ are discussed. Key experimental data are analysed in terms of the theory and essential parameters determined, including the size of the substrate length L involved in regime I growth. The degree of adjacent and/or ‘tight’ folding that obtains in the kinetically-induced lamellar structures is treated as being a function of molecular weight and undercooling. New evidence based on the quantization effect indicates a high degree of adjacent re-entry in regime I for the lower molecular weight fractions. The quality of the chain folding at higher molecular weights in the various regimes is discussed in terms of kinetic, neutron scattering, i.r., and other evidence. Application of the theory to other polymers is discussed briefly.

On the characterization of nonlinear viscoelastic materials

1969-07-01

R. A. Schapery

Abstract Starting with specific constitutive equations, methods of evaluating material properties from experimental data are outlined and then illustrated for some polymeric materials; these equations have been derived from thermodynamic … Abstract Starting with specific constitutive equations, methods of evaluating material properties from experimental data are outlined and then illustrated for some polymeric materials; these equations have been derived from thermodynamic principles, and are very similar to the Boltzmann superposition integral form of linear theory. The experimental basis for two equations under uniaxial loading and the influence of environmental factors on the properties are first examined. It is then shown that creep and recovery data can be conveiently used to evaluate properties in one equation, while two‐step relaxation data serve the same purpose for the second equation. Methods of reducing data to accomplish this characterization and to determine the accuracy of the theory are illustrated using existing data on nitrocellulose film, fiber‐reinforced phenolic resin, and polyisobutylene. Finally, a set of three‐dimensional constitutive equations is proposed which is consistent with nonlinear behavior of some metals and plastics, and which enables all properties to be evaluated from uniaxial creep and recovery data.

A theory for the low-temperature plastic deformation of glassy polymers

1973-10-01

A. S. Argon

Abstract A theory of yielding of glassy polymers by thermally-activated production of local molecular kinks is described. It is possible to obtain the activation free enthalpy of this process by … Abstract A theory of yielding of glassy polymers by thermally-activated production of local molecular kinks is described. It is possible to obtain the activation free enthalpy of this process by modeling the intermolecular energy barrier as resulting from the stress fields of two equal and opposite closely spaced wedge disclination loops extending over the molecular cross section at the points of rotation of the molecular kinks. The theory predicts the yield stress at absolute zero to be dependent only on the shear modulus and the Poisson's ratio, and is capable of describing the temperature, pressure, and strain rate dependences of the flow stress from absolute zero to near the glass transition temperature. Comparison of the theory with the available experimental, results on polystyrene, polyethylene-terephthalate, polycarbonate of bisphenol A, and poly-methyl-methacrylate shows excellent agreement in nearly all respects.

Polymer single crystals☆

1962-01-01

A. Keller

A note on single crystals in polymers: Evidence for a folded chain configuration

1957-09-01

A. Keller

Abstract The morphology and orientation of a number of polymers as crystallized from solution was studied with the electron microscope combined with selected area electron diffraction. In the course of … Abstract The morphology and orientation of a number of polymers as crystallized from solution was studied with the electron microscope combined with selected area electron diffraction. In the course of this work single crystals could be prepared which were most striking in the case of straight chain polyethylenes. There is evidence among others, that the fibrillar (sheaf-type, spherulitic) crystallization, characteristic of polymers, develops through formation of flat single crystals. The single crystals contain screw dislocations and grow by spiral terraces. The observed orientation and the minimum thickness of the crystals leads to the inescapable conclusion that the molecules must bend sharply back on themselves forming a regular folded configuration. Accordingly the strength of the dislocation, consequently the height of growth step, would correspond to the distance between successive bends. Various other observations are consistent with this new concept.

Direct evaluation of the electron density correlation function of partially crystalline polymers

1980-06-01

G. Strobl , M. J. Schneider

Abstract A discussion of the general properties of the one‐dimensional electron density correlation function K ( z ) of a partially crystalline polymer with lamellar structure shows that application of … Abstract A discussion of the general properties of the one‐dimensional electron density correlation function K ( z ) of a partially crystalline polymer with lamellar structure shows that application of a graphical extrapolation procedure permits direct determination of the crystallinity, the specific inner surface, and the electron density difference η c − η a . The procedure is based upon the occurrence of a straight section in the “self‐correlation” range of K ( z ). Curved and nonparallel lamellae do not invalidate the concept. In the case of heterogeneous samples composed of partially crystalline and totally amorphous regions, some of the parameters of the experimentally obtained correlation function, as for example the invariant K (0), are affected and may lose their definiteness. Use of the method is demonstrated in a detailed discussion of the correlation functions measured for a sample of lowdensity polyethylene at 25 and 100°C.

Thermodynamics of fusion of poly-β-propiolactone and poly-ϵ-caprolactone. comparative analysis of the melting of aliphatic polylactone and polyester chains

1972-03-01

V. Crescenzi , Giorgio Manzini , G. Calzolari +1 more

Crystallization behaviour of poly(ether-ether-ketone)

1986-08-01

Peggy Cebe , Su-Don Hong

Errata: The Intrinsic Viscosities and Diffusion Constants of Flexible Macromolecules in Solution

1954-09-01

John G. Kirkwood , Jacob Riseman

First Page First Page

Vibrational Study of the Chain Conformation of the Liquid n-Paraffins and Molten Polyethylene

1967-08-15

Robert G. Snyder

A vibrational and attendant conformational analysis of the liquid n-paraffins and molten polyethylene is presented. For the purposes of the analysis a valence force field was derived which is applicable … A vibrational and attendant conformational analysis of the liquid n-paraffins and molten polyethylene is presented. For the purposes of the analysis a valence force field was derived which is applicable to both planar and nonplanar chains. The force field was evaluated from observed frequencies of trans (T) and gauche (G) n-C4H10; TT and GT n-C5H12; TTT, GTT, and TGT n-C6H14; and (T)∞ polyethylene, all of whose infrared spectra were assigned in detail. Infrared spectra of the liquid-n-paraffins n-C4H10 through n-C17H36 were measured at room temperature and n-C4H10 through n-C12H26 also at a temperature just above their melting point. Frequencies and normal coordinates were calculated for the extended forms and for forms having one gauche bond of n-C4H10 through n-C8H18. These quantities were also calculated for the conformations of n-C5H12 through n-C7H16 having two gauche bonds and for the nonplanar but regular conformations (TG)∞ and (G)∞ of polyethylene. Some bands attributable to forms of n-C5H12 and n-C6H14 having two gauche bonds were found. In the case of n-C5H12 the energy difference between the GT and TT states was found to be nearly the same as that between the GG and GT states. Bands in the region 1400–1300 cm−1 were found to be characteristic of specific conformations involving sequences of five or fewer methylenes, such as —GTTG— (1338 cm−1), —GTG (1368 and 1308 cm−1), —GG— (1352 cm−1), and terminal —TG groups (1344 cm−1). All these bands together with two broader ones centered near 1270 and 1080 cm−1 owe their intensity to the wagging of methylenes adjoining gauche bonds. An interpretation of the general features of the C–C-stretching, methylene-rocking, and methylene-scissoring regions is given. Bands associated with molecules or chains having trans sequences involving at least four methylene groups are found. In the region 1300–1150 cm−1 there are chain-length-dependent band progressions resembling those observed for the crystalline n-paraffins. These indicate the presence of molecules with gauche bonds, but these gauche bonds are few in number and are located near the ends of the chains. It is shown that for certain kinds of vibrations, particularly totally symmetric C–C stretching and ∠CCC bending, there is very little change in frequency in going from a fully extended chain to one having one or even two or more gauche bonds. Hence, it is very difficult in the case of the longer n-paraffins to distinguish spectroscopically between fully extended and almost fully extended conformations.

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Linear method for determining monomer reactivity ratios in copolymerization

1950-04-01

M. A. Fineman , Sidney D. Ross

Drop Breakup and Coalescence in Polymer Blends: The Effects of Concentration and Compatibilization

1995-04-01

Uttandaraman Sundararaj , Christopher W. Macosko

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDrop Breakup and Coalescence in Polymer Blends: The Effects of Concentration and CompatibilizationUttandaraman Sundararaj and C. W. MacoskoCite this: Macromolecules 1995, 28, 8, 2647–2657Publication Date (Print):April 1, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDrop Breakup and Coalescence in Polymer Blends: The Effects of Concentration and CompatibilizationUttandaraman Sundararaj and C. W. MacoskoCite this: Macromolecules 1995, 28, 8, 2647–2657Publication Date (Print):April 1, 1995Publication History Published online1 May 2002Published inissue 1 April 1995https://pubs.acs.org/doi/10.1021/ma00112a009https://doi.org/10.1021/ma00112a009research-articleACS PublicationsRequest reuse permissionsArticle Views4237Altmetric-Citations768LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Parameters characterizing the kinetics of the non-isothermal crystallization of poly(ethylene terephthalate) determined by d.s.c.

1978-10-01

A. Jeziorny

Strategies for compatibilization of polymer blends

1998-01-01

Cor E. Koning , Martin van Duin , Christophe Pagnoulle +1 more

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Structure and properties of isotactic polypropylene

1960-02-01

G. Natta , P. Corradini

Crystalline syndiotactic polystyrene

1986-09-01

Nobuhide Ishihara , Toshiko Seimiya , M. Kuramoto +1 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystalline syndiotactic polystyreneN. Ishihara, T. Seimiya, M. Kuramoto, and M. UoiCite this: Macromolecules 1986, 19, 9, 2464–2465Publication Date (Print):September 1, 1986Publication History Published online1 May 2002Published inissue … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystalline syndiotactic polystyreneN. Ishihara, T. Seimiya, M. Kuramoto, and M. UoiCite this: Macromolecules 1986, 19, 9, 2464–2465Publication Date (Print):September 1, 1986Publication History Published online1 May 2002Published inissue 1 September 1986https://pubs.acs.org/doi/10.1021/ma00163a027https://doi.org/10.1021/ma00163a027research-articleACS PublicationsRequest reuse permissionsArticle Views5165Altmetric-Citations811LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Water absorption and states of water in semicrystalline poly(vinyl alcohol) films

1996-04-01

R. M. Hodge , Graham Edward , George P. Simon

Ultra-high-strength polyethylene filaments by solution spinning/drawing

1980-02-01

Paul Smith , Piet J. Lemstra

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Phase structure and adhesion in polymer blends: A criterion for rubber toughening

1985-11-01

Souheng Wu

β-MODIFICATION OF ISOTACTIC POLYPROPYLENE: PREPARATION, STRUCTURE, PROCESSING, PROPERTIES, AND APPLICATION

2002-01-11

J. Varga

The methods of preparation and formation of supermolecular structures in quiescent and sheared melts and the properties of the β-modification of isotactic polypropylene (β-iPP) are reviewed. The introduction of selective … The methods of preparation and formation of supermolecular structures in quiescent and sheared melts and the properties of the β-modification of isotactic polypropylene (β-iPP) are reviewed. The introduction of selective β-nucleants is the most reliable method for preparation of samples rich in β-modification or of pure β-iPP. The advantages and drawbacks of the known β-nucleating agents are summarized. It is emphasized that pure β-iPP can be prepared under laboratory and processing conditions in the presence of highly active and selective β-nucleants. Nevertheless, there are no literature data—apart from that of the author's groups—which evidenced unambiguously the formation of pure β-iPP. It hints at the insufficient selectivity of β-nucleants used or at the inappropriate crystallization or melting conditions applied by other scientists. The structure formation during the high-temperature hedritic crystallization is discussed comprehensively and illustrated by polarized light microscopy and scanning electron microscopy micrographs. Some specific features of β-iPP, namely the high- and low-temperature growth transition, the restricted temperature range of the formation of pure β-iPP, and the unique melting and recrystallization characteristics (melting and annealing memory effect) are summarized. It was emphasized that impact strength and toughness of β-iPP markedly exceed those of α-iPP. Processing of β-nucleated iPP and application of β-nucleated iPP is described briefly.

Connection between Polymer Molecular Weight, Density, Chain Dimensions, and Melt Viscoelastic Properties

1994-08-01

Lewis J. Fetters , David J. Lohse , Dieter Richter +2 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConnection between Polymer Molecular Weight, Density, Chain Dimensions, and Melt Viscoelastic PropertiesL. J. Fetters, D. J. Lohse, D. Richter, T. A. Witten, and A. ZirkelCite this: Macromolecules … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConnection between Polymer Molecular Weight, Density, Chain Dimensions, and Melt Viscoelastic PropertiesL. J. Fetters, D. J. Lohse, D. Richter, T. A. Witten, and A. ZirkelCite this: Macromolecules 1994, 27, 17, 4639–4647Publication Date (Print):August 1, 1994Publication History Published online1 May 2002Published inissue 1 August 1994https://pubs.acs.org/doi/10.1021/ma00095a001https://doi.org/10.1021/ma00095a001research-articleACS PublicationsRequest reuse permissionsArticle Views17234Altmetric-Citations1735LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The Physics of Glassy Polymers

1974-04-01

R. N. Haward , Richard E. Robertson

(The Nature of Polymer Glasses, Their Packing Density and Mechanical Behaviour).- The Nature of Polymeric Glasses.- The common glassy polymers.- The softening of polymer glasses.- Polymer melts and rubbers.- The … (The Nature of Polymer Glasses, Their Packing Density and Mechanical Behaviour).- The Nature of Polymeric Glasses.- The common glassy polymers.- The softening of polymer glasses.- Polymer melts and rubbers.- The crystallisation of polymers.- Amorphous isotactic polymers.- The morphology of amorphous polymers.- Packing Volume in the Glassy State.- The expansion volume of amorphous polymers.- Free volume concepts derived from viscosity theories.- Viscosity and free volume in polymers.- Geometrical factors affecting the possible value of the free volume at Tg.- Bernal's random close packed volume.- The Rigidity of Polymer Glasses.- Large Deformations and Fracture.- References.- 1 The Thermodynamics of the Glassy State.- 1.1 Introductory Thermodynamic Considerations.- 1.2 Glassy Solidification and Transition Phenomena.- 1.2.1 General considerations and transitions of different order.- 1.2.2 Glassy solidification with one or several internal parameters.- 1.2.3 Experimental results.- 1.2.4 Position of the equilibrium curve below the glass temperature.- 1.2.5 Zero point volume of a polymer.- 1.3 Results of the Thermodynamic Theory of Linear Relaxation Phenomena.- 1.4 Glassy Mixed Phases.- 1.4.1 The glassy solidification of polymer solutions.- 1.4.2 The glassy solidification of cross-linked systems. The coexistence of glassy phases with phases in internal equilibrium.- 1.5 The Mobility and Structure of Glassy Phases.- References.- 2 X-Ray Diffraction Studies of the Structure of Amorphous Polymers.- 2.1 Introduction.- 2.2 The Interaction of X-rays With Matter.- 2.2.1 Scattering by a free electron.- 2.2.2 Interference among scattered waves.- 2.2.3 Atomic scattering factor.- 2.2.4 Compton scattering.- 2.3 Order and Orientation in Polymers.- 2.3.1 Order.- 2.3.2 Orientation.- 2.4 Diffraction of X-rays by Amorphous Materials.- 2.5 Small Angle X-ray Scattering.- 2.5.1 Introduction.- 2.5.2 Experimental requirements for SAXS.- 2.5.3 Outline of the theory of SAXS.- 2.5.4 Some applications of SAXS.- 2.6 The Radial Distribution Function for Amorphous Polymers.- References.- 3 Relaxation Processes in Amorphous Polymers.- 3.1 Introduction.- 3.2 Molecular Motion in Polymeric Melts and Glasses.- 3.2.1 General description of relaxational processes.- 3.2.2 Relaxational processes at the crystal melt temperature.- 3.2.3 Relaxations in the amorphous state above Tg and below Tm.- 3.2.4 Relaxational processes at the glass transition.- 3.2.5 Relaxations in the glassy state.- 3.3 Secondary Relaxation Regions in Typical Organic Glasses.- 3.3.1 Secondary relaxation regions in Polyvinylchloride.- 3.3.2 Secondary relaxation regions in polystyrene.- 3.3.3 Secondary relaxations in polymethylmethacrylate.- References.- 4 Creep in Glassy Polymers.- 4.1 Introduction.- 4.2 Phenomenological Theory of Creep.- 4.2.1 Linear theory.- 4.2.2 Nonlinear theory-creep equations.- 4.2.3 Nonlinear theory-superposition rules.- 4.3 Apparatus and Experimental Methods.- 4.3.1 General principles.- 4.3.2 Special experimental requirements.- 4.3.3 Special experiments.- 4.4 Creep Phenomena in Glassy Polymers.- 4.4.1 Typical creep behaviour.- 4.4.2 Creep at elevated temperatures.- 4.4.3 Creep in anisotropic samples.- 4.4.4 Recovery behaviour.- 4.4.5 Creep under intermittent stress.- 4.4.6 Creep under abrupt changes of stress.- 4.5 Final Comments.- References and Bibliography.- 5 The Yield Behaviour of Glassy Polymers.- 5.1 Introduction.- 5.2 Exact Definitions.- 5.2.1 Stress.- 5.2.2 Strain.- 5.2.3 The deformation-rate tensor.- 5.2.4 The yield point.- 5.2.5 Nomenclature for deformation processes.- 5.3 Mechanical Tests.- 5.3.1 The tensile test.- 5.3.2 The uniaxial compression test.- 5.3.3 The plane strain compression test.- 5.3.4 Tests in simple shear.- 5.3.5 Machine elasticity.- 5.3.6 Drawing at constant load.- 5.4 Characteristics of the Yield Process.- 5.4.1 The yield point and the yield stress.- 5.4.2 The yield strain.- 5.4.3 Strain softening and orientation hardening.- 5.4.4 The strain-rate dependence of the yield stress.- 5.4.5 The temperature dependence of the yield stress and the yield strain.- 5.4.6 The effect of hydrostatic pressure on the yield stress and yield strain.- 5.4.7 The effect of polymer structure on the yield stress.- 5.4.8 Volume changes at yield.- 5.4.9 The Bauschinger effect.- 5.5 Inhomogeneous Deformation.- 5.5.1 The reasons for inhomogeneous deformation.- 5.5.2 The principle of maximum plastic resistance.- 5.5.3 The geometry of inhomogeneous deformation.- 5.5.4 Strain inhomogeneities in polymers.- 5.6 Structural Observations.- 5.6.1 Birefringence.- 5.6.2 Electron microscopy.- 5.7 Yield Criteria for Polymers.- 5.7.1 The Tresca yield criterion.- 5.7.2 The von Mises yield criterion.- 5.7.3 The Mohr-Coulomb yield criterion.- 5.7.4 The modified Tresca criterion.- 5.7.5 The modified von Mises criterion.- 5.7.6 Choice of a yield criterion for polymers.- 5.8 Molecular Theories of Yielding.- 5.8.1 Reduction of the Tg by the applied stress.- 5.8.2 Stress-induced increase in free volume.- 5.8.3 Break-down of entanglements under stress.- 5.8.4 The Eyring model.- 5.8.5 The Robertson model.- 5.8.6 The theoretical shear strength-Frank's modification of the Frenkel model.- 5.8.7 Disclinations.- References.- 6 The Post-Yield Behaviour of Amorphous Plastics.- 6.1 General.- 6.2 The Phenomena of' strain Softening'.- 6.2.1 Stress hardening.- 6.3 Plastic Instability Phenomena.- 6.3.1 Plastic instability in tension.- 6.3.2 Plastic instability in different stress fields.- 6.4 The Adiabatic Heating of Polymers Subject to Large Deformations.- 6.4.1 Reversible thermoelastic effect.- 6.4.2 Thermal effects in large plastic deformation.- 6.4.3 The experimental measurement of temperature changes during deformation.- 6.5 Orientation Hardening.- 6.5.1 Orientation hardening as a physical process.- 6.5.2 Factors affecting orientation hardening.- 6.5.3 A model for large polymer deformations.- 6.6 Large Deformation and Fracture.- 6.6.1 Crack propagation as a deformation process.- 6.6.2 Crazing as a plastic instability phenomenon.- 6.6.3 The growth of voids in a polymer glass.- 6.6.4 The nucleation of voids.- References.- 7 Cracking and Crazing in Polymeric Glasses.- 7.1 Introduction.- 7.2 Fracture Mechanics.- 7.2.1 Linear fracture mechanics.- 7.2.2 Measurements of KIC for glassy polymers.- 7.2.3 Crack-opening displacement.- 7.2.4 Energy balance approach.- 7.2.5 Measurements of surface work.- 7.2.6 Fracture stress.- 7.3 Fatigue Fracture.- 7.3.1 Fatigue failure by heat build-up.- 7.3.2 Fatigue crack propagation.- 7.4 Crazing.- 7.4.1 Crazing of glassy plastics in air.- 7.4.2 Environmental crazing.- 7.4.3 Theoretical aspects.- 7.5 Molecular Fracture.- 7.5.1 Kinetic theories of fracture.- 7.5.2 Experimental evidence for bond fracture.- 7.6 Conclusion.- References.- 8 Rubber ReinForced Thermoplastics.- 8.1 Introduction.- 8.2 Rubber Reinforced Glassy Polymers of Commercial Importance.- 8.2.1 Based on polystyrene.- 8.2.2 Based on styrene acrylonitrile copolymer (SAN).- 8.2.3 Based on Polyvinylchloride.- 8.3 Methods of Manufacture.- 8.3.1 Physical blending.- 8.3.2 Interpolymerisation process.- 8.3.3 Latex interpolymerisation.- 8.4 Incompatibility in Polymer Mixtures.- 8.5 Identification of Two Phase Rubber Reinforced Systems.- 8.6 Dispersed Phase Morphology.- 8.6.1 Toughened polystyrene.- 8.6.2 ABS copolymers.- 8.6.3 Polyvinylchloride.- 8.7 Optical Properties.- 8.7.1 Matching of the refractive index.- 8.7.2 Reduction in particle size.- 8.8 Mechanical Properties.- 8.8.1 Tensile properties.- 8.8.2 Dynamic mechanical properties.- 8.8.3 Impact properties.- 8.8.4 Structure-property relationships.- References.- 9 The Diffusion and Sorption of Gases and Vapours in Glassy Polymers.- 9.1 Introduction.- 9.2 Ideal and Non-ideal Sorption and Diffusion of Fixed Gases.- 9.2.1 Ideal diffusion and sorption of fixed gases.- 9.2.2 Non-ideal sorption and diffusion of fixed gases.- 9.3 The Effect of the Glass Transition on Gas and Vapour Diffusion in Polymers.- 9.4 Relaxation Controlled Transport and Related Crazing of Polymeric Glasses by Vapours.- 9.4.1 Introduction ..- 9.4.2 Relaxation controlled transport and solvent crazing.- 9.5 Some Effects of Crystallinity and Orientation on the Transport of Gases and Vapours in Glassy Polymers.- 9.5.1 Effect of crystallinity.- 9.5.2 The effect of orientation.- References.- 10 The Morphology of Regular Block Copolymers.- 10.1 Introduction.- 10.1.1 General.- 10.1.2 Microphase separation.- 10.2 Techniques Used for the Study of the Morphology of Block Copolymers.- 10.2.1 Low angle X-ray scattering.- 10.2.2 Electron microscopy.- 10.2.3 Other techniques.- 10.3 Variables Controlling the Morphology.- 10.3.1 Chemical variables.- 10.3.2 Physical variables.- 10.4 Studies with Specific Systems.- 10.4.1 Systems with liquid.- 10.4.2 The pure copolymers.- 10.5 Theories of the Morphology of Block Copolymers.- 10.5.1 Objectives.- 10.5.2 Principles of calculation.- 10.6 Implications of Theories and Comparison With Experiment.- 10.6.1 Influence of block molecular weight ratio.- 10.6.2 Effect of block molecular weights.- 10.6.3 Molecular orientation in the phases.- 10.6.4 Interfacial region.- 10.6.5 Effect of temperature on domain size.- 10.7 Mechanical Properties and Deformations.- 10.8 Crystallinity.- References.- Appendix I Glass Transition Temperatures and Expansion Coefficients for the Glass and Rubber States of some Typical Polymeric Glasses.- Appendix II Conversion Factors for SI Units.

Properties and Structure of Polymers

1960-01-01

A. V. Tobolsky , Thomas D. Callinan

Melting Point Depression and Kinetic Effects of Cooling on Crystallization in Poly(vinylidene fluoride)-Poly(methyl methacrylate) Mixtures

1975-11-01

Toshio Nishi , T. T. Wang

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMelting Point Depression and Kinetic Effects of Cooling on Crystallization in Poly(vinylidene fluoride)-Poly(methyl methacrylate) MixturesT. Nishi and T. T. WangCite this: Macromolecules 1975, 8, 6, 909–915Publication Date … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMelting Point Depression and Kinetic Effects of Cooling on Crystallization in Poly(vinylidene fluoride)-Poly(methyl methacrylate) MixturesT. Nishi and T. T. WangCite this: Macromolecules 1975, 8, 6, 909–915Publication Date (Print):November 1, 1975Publication History Published online1 May 2002Published inissue 1 November 1975https://pubs.acs.org/doi/10.1021/ma60048a040https://doi.org/10.1021/ma60048a040research-articleACS PublicationsRequest reuse permissionsArticle Views5037Altmetric-Citations1222LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Fracture Behaviour of Polymers

1995-01-01

A. J. Kinloch , R. J. Young

Recycling of PET

2005-03-17

Firas Awaja , Dumitru Pavel

Formation of dispersed phase in incompatible polymer blends: Interfacial and rheological effects

1987-03-01

Souheng Wu

Abstract The formation of dispersed phase in blends of incompatible polymers during melt extrusion with a co‐rotating twin screw extruder was studied, using nylon and polyester as the matrix and … Abstract The formation of dispersed phase in blends of incompatible polymers during melt extrusion with a co‐rotating twin screw extruder was studied, using nylon and polyester as the matrix and ethylene‐propylene rubbers as the dispersed phase. A master curve is obtained, i.e., G η m α/γ = 4 p ±0.84 , where G is the shear rate, γ the particle diameter, η the interfacial tension, η m the matrix viscosity, η d the dispersed‐drop viscosity, and p = η d /η m . The plus (+) sign applies for p > 1, and the minus (−) sign for p < 1. Thus, the dispersed‐drop size is directly proportional to the interfacial tension and the ±0.84 power of viscosity ratio. The dispersed drops are the smaller, when the interfacial tension is the lower and the viscosity ratio is the closer to unity. The interfacial tension is largely controlled by the polarities of the two phases, and can be varied over several orders of magnitude by using appropriate dispersants.

Polymer—Polymer Miscibility

1980-12-01

W. Funke

Water structure and changes in thermal stability of the system poly(ethylene oxide)–water

1981-01-01

Roland Kjellander , Ebba Florin

The phase behaviour of aqueous solutions of poly(ethylene oxide), PEO, is analysed by means of a structural model of the system and a simple statistical-mechanical model based thereupon. The intention … The phase behaviour of aqueous solutions of poly(ethylene oxide), PEO, is analysed by means of a structural model of the system and a simple statistical-mechanical model based thereupon. The intention is to elucidate the structural questions involved in the water–PEO coupling and to gain some insight in possible consequences of this coupling. The experimental partial molar enthalpy and entropy of water can be reproduced, at least in fairly dilute solutions, if a zone with increased structuring of the water is assumed to exist around the PEO chain. The phase separation that takes place at high temperatures is traced back to the increase in total extension of the zones of enhanced water structure that occurs when the water content is increased. The chain-length dependence of the location of the solubility gap is mainly determined by the combinatorial entropy of the chains. The water solubility of PEO, which is unique in this respect among the polyethers, can be explained in terms of a good strutural fit between the water and the polymer.

Effect of crystallization temperature on the crystalline phase content and morphology of poly(vinylidene fluoride)

1994-04-15

R. Gregório , Marcelo Cestari

Abstract The effect of temperature on the crystallization of α, β, and γ phases of PVDF from dimethylacetamide (DMA) solution was studied. Variation in the crystallinity content of these three … Abstract The effect of temperature on the crystallization of α, β, and γ phases of PVDF from dimethylacetamide (DMA) solution was studied. Variation in the crystallinity content of these three phases was obtained as a function of temperature using infrared spectroscopy, differential scanning calorimetry (DSC) and x‐ray diffraction techniques. Such variation is related to the dependence of the crystallization rate of each phase with temperature, and allowed a better understanding of some results found in the literature about the crystallization and interconversion of these phases. Micrographs of samples present morphologies that corroborate with the proposed explanations. © 1994 John Wiley & Sons, Inc.

The crystal structure of polycaproamide: Nylon 6

1955-06-01

David R. Holmes , C. W. Bunn , David J. Smith

Abstract The crystal structure of nylon 6 (NH (CH 2 ) 5 CO) p has been determined by interpretation of the x‐ray diffraction patterns given by drawn, rolled fibers. The … Abstract The crystal structure of nylon 6 (NH (CH 2 ) 5 CO) p has been determined by interpretation of the x‐ray diffraction patterns given by drawn, rolled fibers. The determination was part of a program to investigate the relation between structure and physical properties, in particular melting point. Nylon 6 melts 50°C. lower than its isomer nylon 66 (NH (CH 2 ) 6 NH·CO (CH 2 ) 4 CO) p ; it had been suggested that this was due to deficient hydrogen‐bond formation in nylon 6 crystallites. The unit cell contains eight chemical units (NH (CH 2 ) 5 CO) and is monoclinic with a = 9.56 A., b = 17.24 A., c = 8.01 A., and β = 67 1/2 °. Calculated density = 1.23. Observed density for a drawn monofilament = 1.16. The structure consists of planar chains of CH 2 groups and amide groups tilted 7° from the (001) plane. Alternate chains in this plane are oppositely directed, an arrangement which allows all hydrogen bonds to be made perfectly. The hydrogen‐bonded sheets of atoms are packed in an “up‐and‐down” staggered configuration along the c ‐axis. Distances between atoms in neighboring molecules are all normal van der Waals contact distances. It appears, from a general survey of polyamide melting points published elsewhere, that the determining factor is the number of CH 2 groups between the amide “anchor points”—polymers with odd numbers of CH 2 groups melt lower than those with even numbers. The present work shows that the odd number of CH 2 groups in this polymer does not lead to deficient hydrogenbond formation, and that the lower melting point of nylon 6 as compared with nylon 66 must be ascribed to some other cause, possibly connected with the propagation of vibrations along odd‐numbered chain segments.

The Relation of Transition Temperatures to Chemical Structure in High Polymers

1963-11-01

Raymond F. Boyer

Abstract The primary purpose of this paper is to summarize some of the general relationships between chemical structure and transition temperatures for polymers. In addition to the two primary transitions, … Abstract The primary purpose of this paper is to summarize some of the general relationships between chemical structure and transition temperatures for polymers. In addition to the two primary transitions, the melting point Tm, and the glass transition TG, other transitions occurring either below TG or between TG and Tm are discussed. A secondary purpose of this paper is to make a preliminary attempt at some rational nomenclature and classification scheme for polymer transitions, especially in the case of polymers having multiple transitions. This article is not intended to be a complete review of the literature on transitions in polymers. Our paper was inspired by a comprehensive lecture on multiple transitions presented by Dr. Karl Wolf in Midland, Michigan, during the summer of 1960. The substance of this lecture has recently been published. Willbourn has also been concerned with the classification of multiple transitions. A recent comprehensive report by Saito, Okano, Iwayanagi and Hideshima called “Molecular Motion in Solid State Polymers” also considers in elaborate detail many of these same problems.

Scaling concepts in polymer physics

1981-04-01

M. Gordon

Melting process and the equilibrium melting temperature of polychlorotrifluoroethylene

1962-01-01

John D. Hoffman , James J. Weeks

Octobcr 2, Octobcr 2,

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Theory of formation of polymer crystals with folded chains in dilute solution

1960-01-01

John I. Lauritzen , John D. Hoffman

A detailed interpretation of the kinetics of homogeneous nucleation and growth of crystals of a linear homopolymer from dilute solution is given. The probability of forming both nuclei with folded … A detailed interpretation of the kinetics of homogeneous nucleation and growth of crystals of a linear homopolymer from dilute solution is given. The probability of forming both nuclei with folded chains, and conventional bundlelike nuclei, from dilute solution is analyzed. It is predicted that at sufficiently high dilution, critical nuclei of length

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Handbook of Thermoplastics

2015-12-11

Conventional polyolefins new polyolefins stereoregular polar thermoplastics syndiotactic polystyrene unplasticized polyvinyl chloride (uPVC) - fracture and fatigue properties acrylonitrile-butadiene-styrene (ABS) polymers styrene copolymers polyacrylonitrile polyacrylates polyacrylamides vinyl acetate polymers vinyl … Conventional polyolefins new polyolefins stereoregular polar thermoplastics syndiotactic polystyrene unplasticized polyvinyl chloride (uPVC) - fracture and fatigue properties acrylonitrile-butadiene-styrene (ABS) polymers styrene copolymers polyacrylonitrile polyacrylates polyacrylamides vinyl acetate polymers vinyl alcohol polymers synthetic water-soluble polymers cellulose plastics thermoplastic elastomers thermplastic polyurethanes polyester-based thermplastic elastomers polybutylene terephthalate compatibilized thermoplastic blends toughening of thermoplastics polyacetal polyether polyarylates polycarbonates polyamides polyimides polybenzimidazoles aromatic polyhydrazides and their corresponding polyoxadiazoles polyphenylquinoxalines polyphenylene sulfide polyphenylene vinylene conducting thermoplastics conducting thermoplastics composites poly(aryl ether sulfone)s poly(aryl ether ketone)s poly(aryl ether ketones-co-sulfones) poly(aryl ether ketone amide)s polytetrafluoroethylene liquid crystalline polymers advanced thermoplastics composites.

Nonisothermal melt and cold crystallization kinetics of poly(aryl ether ether ketone ketone)

1997-03-01

Tianxi Liu , Zhishen Mo , Shanger Wang +1 more

Abstract Analysis of the nonisothermal melt and cold crystallization kinetics of poly(aryl ether ether ketone ketone) (PEEKK) was performed by using differential scanning calorimetry (DSC). The Avrami equation modified by … Abstract Analysis of the nonisothermal melt and cold crystallization kinetics of poly(aryl ether ether ketone ketone) (PEEKK) was performed by using differential scanning calorimetry (DSC). The Avrami equation modified by Jeziorny could describe only the primary stage of nonisothermal crystallization of PEEKK. And, the Ozawa analysis, when applied to this polymer system, failed to describe its nonisothermal crystallization behavior. A new and convenient approach for the nonisothermal crystallization was proposed by combining the Avrami equation with the Ozawa equation. By evaluating the kinetic parameters in this approach, the crystallization behavior of PEEKK was analyzed. According to the Kissinger method, the activation energies were determined to be 189 and 328 kJ/mol for nonisothermal melt and cold crystallization, respectively.

Polymer–Polymer Miscibility

1979-01-01

Olagoke Olabisi , Lloyd M. Robeson , Montgomery T. Shaw

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Thermodynamics of High Polymer Solutions

1941-08-01

Paul J. Flory

First Page First Page

Physical aging in amorphous polymers and other materials

1979-02-01

R. N. Haward

Flow Modification Effects and Mechanisms of Silicone Powder and PEG on UHMWPE/HDPE Blends: Insights from Experimental and Molecular Dynamics Simulations

2025-06-25

Gonghao Wang , Jie Liu , Shengxue Qin +2 more | The Journal of Physical Chemistry B

The high melt viscosity and poor flowability of ultrahigh molecular weight polyethylene (UHMWPE) hinder its spinning production efficiency and industrial-scale processing. In this study, a blend of UHMWPE and high-density … The high melt viscosity and poor flowability of ultrahigh molecular weight polyethylene (UHMWPE) hinder its spinning production efficiency and industrial-scale processing. In this study, a blend of UHMWPE and high-density polyethylene (HDPE) was modified by incorporating silicone powder and polyethylene glycol (PEG). By integrating experimental characterization with molecular dynamics simulations, this study investigates the effects and underlying mechanisms of flow modification induced by the individual and synergistic incorporation of PEG and silicone powder into UHMWPE/HDPE blends at both macroscopic and molecular levels. Experimental results showed that 1 wt % PEG provided the most significant modification effect on the UHMWPE/HDPE blend. Compared to the unmodified UHMWPE/HDPE blend, the processing torque and flow activation energy decreased by 22.1% and 34.57%, respectively, and the melt flow rate increased by 48.04%. However, a slight reduction in tensile properties was observed, with the tensile strength decreasing by 5.09%. Molecular dynamics simulations revealed that the addition of 1 wt % PEG notably enhanced the overall mobility of the molecular chains in the UHMWPE/HDPE blend, leading to the highest free volume fraction and diffusion coefficient, thus improving flowability. However, the intermolecular interactions within the blend were relatively weak, resulting in lower cohesive energy density and interaction energy, which, in turn, reduced mechanical properties. The experimental and simulation results are in good agreement and provide valuable insights into the modification effects and mechanisms of different flow additives, offering guidance for the selection and optimization of modification formulations for UHMWPE.

Melt strain hardening of various high density polyethylenes

2025-06-24

Helmut Münstedt , Joachim Kaschta | Journal of Rheology

Strain hardening of polymer melts is a rheological property interesting from an application and a fundamental point of view. While strain hardening of long-chain branched polyethylenes and polypropylenes and their … Strain hardening of polymer melts is a rheological property interesting from an application and a fundamental point of view. While strain hardening of long-chain branched polyethylenes and polypropylenes and their relation to the molecular structure have widely been discussed in the literature, there are only few publications on the behavior of polyethylenes of high density (HDPE). Moreover, the results available from the literature are different with respect to the dependence of strain hardening on the elongational rate. Some samples show a negligible strain hardening, but most of them reveal hardening increasing with the decreasing rate. The lack of comprehensive molecular characterizations restricts a deeper understanding. Thus, in this work, the elongational behavior of various HDPEs was studied and their molecular structure characterized using high-temperature gel-permeation chromatography coupled with laser-light scattering at small elution volumes. In addition, the zero-shear viscosity as a function of molar mass was considered. It was found that molecules of very high molar masses or few long branches effecting long relaxation times may be the reason for strain hardening increasing with the decreasing rate. The underlying chemical reaction is not understood in detail, but it seems very probable that the catalysts and the processes used for the polymerization of HDPE may be able to generate molecular structures with a strong effect on strain hardening.

Regulated β‐phase crystallization of strong and tough polypropylene through hyperbranched topology

2025-06-24

Can Jiang , Guilian Shi , Tingcheng Li +2 more | Chemistry - A European Journal

Achieving both enhanced strength and improved toughness of polypropylene (PP) remains a significant challenge for industrial applications. The present study addresses this limitation by constructing a robust crystalline network through … Achieving both enhanced strength and improved toughness of polypropylene (PP) remains a significant challenge for industrial applications. The present study addresses this limitation by constructing a robust crystalline network through the strategic integration of hyperbranched topology. We demonstrate that a hyperbranched nucleating agent (HBPN) effectively induces high-content β-crystal formation in PP, which organizes into an interconnected crystalline architecture. This β-phase network significantly enhances the mechanical performance of PP, with tensile strength and notched impact strength increasing by 35.78 % (to 42.5 MPa) and 140 % (to 13.2 KJ/m²), respectively, compared to pure PP. Mechanistic studies reveal that the synergy between strength and toughness originates from HBPN mediated β-phase crystallization, which refines the morphology of spherulites and increases the degree of crystallinity. The hyperbranched topology of HBPN inhibits entangled PP chains and facilitates crystallization of PP chains. Thus, it contributes efficient stress redistribution by dissipating localized energy through multidirectional load transfer, while arresting crack advancement via microvoid-induced stress relaxation. This work demonstrates an effective conceptual approach to engineering high-performance PP, unlocking its potential for various value-added applications.

Gamma Irradiation-Induced Changes in Microstructure of Cyclic Olefin Copolymer (COC) Revealed by NMR and SAXS Characterization

2025-06-24

Fan Zhang , Heng Lei , Feng Guo +6 more | Polymers

Cyclic Olefin Copolymer (COC) is an amorphous thermoplastic polymer synthesized through the catalytic copolymerization of α-olefin and cyclic olefin. When used in pre-filled syringes and pharmaceutical packaging, COCs require radiation … Cyclic Olefin Copolymer (COC) is an amorphous thermoplastic polymer synthesized through the catalytic copolymerization of α-olefin and cyclic olefin. When used in pre-filled syringes and pharmaceutical packaging, COCs require radiation sterilization. The radiation sterilization alters the microstructure of COC, which ultimately affects its performance and biosafety. In this study, to investigate the effects of γ-radiation on COC microstructures, ethylene-norbornene copolymers with various compositions, representative of COC, are studied by nuclear magnetic resonance (NMR) and small angle X-ray scattering (SAXS) techniques. During irradiation, the COC containing 35 mol% norbornene produced free radicals that triggered migration and reaction processes, leading to the formation of entanglements within flexible chain segments. This, in turn, affected nearby ring structures with high steric hindrance, resulting in a 9.2% decrease in internal particle size and an increase in particle spacing. Conversely, when the norbornene content in COC was increased to 57 mol%, the internal particle size increased by 17.9%, while the particle spacing decreased.

Interactions of insulin aspart hexamer and excipients with plasticized polyvinyl chloride surfaces: A comprehensive investigation combining molecular simulations and experiments

2025-06-24

Pierre Fayon , Philip Chennell , Mehdi Sahihi +7 more | International Journal of Biological Macromolecules

Insulin aspart is a major therapeutic biomacromolecule used worldwide for the treatment of diabetes mellitus. It is administered either subcutaneously or intravenously, using infusion lines made most often from plasticized … Insulin aspart is a major therapeutic biomacromolecule used worldwide for the treatment of diabetes mellitus. It is administered either subcutaneously or intravenously, using infusion lines made most often from plasticized polyvinyl chloride (PVC). Unfortunately, its very nature makes it at high risk of surface interactions with the materials it can come into contact with, leading notably to greatly decreased concentrations and patient underdosing. In order to prevent this phenomenon, for which no adequate solution yet exists, in-depth knowledge of the behaviour of insulin aspart at the water-solid interface is needed. The aim of this work was to shed new light on this highly problematic interaction and explain the adsorption phenomenon of insulin aspart and its phenolic excipients (phenol and metacresol) to plasticized PVC tubings from a thermodynamic point of view by combining experimental and molecular dynamics simulations. Our results proved that the hexameric form of insulin aspart possesses an important affinity for the PVC surface, to which it adsorbs nearly instantaneously to, whilst phenol and metacresol interacts with the PVC/plasticizer interface of the material. The molecular simulations of these surface interactions correlate well with the sorption processes that can be assumed to happen with the negatively charged PVC surfaces. Thermodynamic values obtained via the molecular simulation process were used to model succesfully the experimental data. This combination of theoretical approaches could help us in predicting the risk of interfacial interactions in biomacromolecular systems.

Thermal degradation of impact‐modified <scp>PMMA</scp> in mechanical and chemical recycling

2025-06-22

Nguyen Tien Dat , Nooshin Saadatkhah , Yanfa Zhuang +4 more | The Canadian Journal of Chemical Engineering

Abstract Poly (methyl methacrylate) (PMMA) is a thermoplastic with outstanding tensile strength, UV resistance, and a high level of transparency that has been used widely for optical applications such as … Abstract Poly (methyl methacrylate) (PMMA) is a thermoplastic with outstanding tensile strength, UV resistance, and a high level of transparency that has been used widely for optical applications such as glazing in the automobile industry. Mechanical recycling, the most widespread method, degrades the physical properties and prevents reusing PMMA in transparent applications. Thermal depolymerization to recover methyl methacrylate (MMA) monomer is becoming an alternative route for PMMA recycling. In this paper, the thermal depolymerization process of impact‐modified PMMA in a micro fluidized bed reactor was investigated. The pyrolysis was conducted over aluminium oxide () and fluid‐cracking catalyst (FCC) as catalytic beds; sand and SiC as inert beds at temperatures below . A mechanical recycling process was also simulated using sequential injection moulding to investigate its impact on the properties of PMMA. After 5 cycles of injection moulding, the impact strength and optical properties of PMMA were severely diminished due to an increase in free volume and partial thermal degradation. Regarding PMMA pyrolysis, demonstrated limited cracking ability with a maximum MMA yield of 46%, as opposed to FCC, which over‐cracked both PMMA and MMA into coke and unwanted products. In contrast, non‐catalytic beds exhibited higher activity for MMA recovery, with SiC yielding the highest amount of 92% at .

Universal negative energetic elasticity in polymer chains: Crossovers among random, self-avoiding, and neighbor-avoiding walks

2025-06-20

NULL AUTHOR_ID | Physical review. E

Identification of Phase-Separated Structures and Polymer Crystals Inside Polyolefin Blends

2025-06-20

Shusuke Kanomi , Tomohiro Miyata , Hiroshi Jinnai | Micron

In situ Photo-rheology Monitors Viscoelastic Changes in Photo-responsive Polymer Networks

2025-06-20

Eleanor Quirk , Michael C. Burroughs , J. Danielle | Journal of Visualized Experiments

On the applicability of the load separation criterion to the fracture characterisation of thermoplastic elastomers

2025-06-19

Stefano Gozzini , Jacopo Agnelli , Silvia Agnelli +3 more | Research Square (Research Square)

<title>Abstract</title> Initially proposed for metals and then extended to polymeric materials, the Load Separation Criterion, LSC, is the theoretical basis of several laboratory test methods for the fracture characterisation of … <title>Abstract</title> Initially proposed for metals and then extended to polymeric materials, the Load Separation Criterion, LSC, is the theoretical basis of several laboratory test methods for the fracture characterisation of materials exhibiting plasticity. In this work, the applicability of the LSC to the fracture characterisation of thermoplastic elastomers, TPEs, was analysed and discussed for the first time. Due to their peculiar nature, TPEs combine melt state processability with a high compliance and elasticity typical of rubbers. At a macroscopic scale, their mechanical response appears generally complex, with an evident viscoelastic character coupled with clear signs of plasticity (behaviour often referred to as of the elastoviscoplastic type). Three industrially relevant TPEs, differing for the chemical nature, were examined. First, their stress-strain behaviour was studied by uniaxial tensile tests, carried out on dumb-bell specimens. Then, to verify the load separability, single-edge notched in tension, SENT, tests were carried out on blunt-notched specimens (stationary crack tests under plane stress conditions). Specimens with different crack-length/width ratios were tested at room temperature and with a fixed crosshead speed (low rate). The LSC proved to be valid for all three TPEs studied.

Effect of the Structure of the Modifying Polyolefin Fraction on the Deformation and Strength Properties of Reactor Polymer Compositions Based on Ultrahigh Molecular Weight Polyethylene

2025-06-19

E. E. Starchak , Т. М. Ушакова , S. S. Gostev +3 more | Polymer Science Series A

Correlation between interaction parameters and crystal morphology in PCL/CPE blends with varying chlorine in CPE

2025-06-19

Al Mamun | Journal of Elastomers & Plastics

The correlation between the interaction parameters and crystal morphology in binary blends of poly(ε-caprolactone) (PCL) and chlorinated polyethylene (CPE) with varying chlorine content was investigated. Melting-point depression analysis provided quantitative … The correlation between the interaction parameters and crystal morphology in binary blends of poly(ε-caprolactone) (PCL) and chlorinated polyethylene (CPE) with varying chlorine content was investigated. Melting-point depression analysis provided quantitative evidence of partial miscibility between PCL and CPE, with stronger interactions observed at higher chlorine levels. The interaction energy density (B) decreases linearly with increasing chlorine content, indicating improved miscibility and potentially more homogeneous blends at higher chlorine concentrations. Morphological analysis revealed significant changes in PCL crystal shape with varying CPE and Cl concentrations. Pure PCL formed truncated lozenge-shaped crystals, whereas the addition of CPE resulted in curved S-shaped crystals with increasing bending angle. The crystal growth rate decreased with increasing CPE content, with a more pronounced effect observed for higher chlorine contents in the CPE. Atomic force microscopy analysis of ultrathin films revealed dendritic crystalline structures, suggesting diffusion-limited growth mechanisms influenced by the polymer chain mobility and crystallization rates. The chlorine content in CPE significantly affected its surface morphology, with a higher chlorine content promoting a more perfect crystalline structure. These findings advance our understanding of the structure-property correlations in PCL/CPE blends, offering valuable insights for tailoring blend characteristics to meet specific application requirements, especially in fields demanding precise regulation of compatibility and performance metrics.

Revisiting polymer crystallization kinetics: experimental validation of the Mo equation for modified PET systems

2025-06-19

Ma Lingcong , Mao Fengyu , WU Ya-juan +3 more | Frontiers in Materials

This study investigated the non—isothermal crystallization kinetics of pure poly(ethylene terephthalate) (PET) and chain—extended modified PET using DSC at various cooling rates. Through comparing Avrami, Ozawa, and Mo methods, the … This study investigated the non—isothermal crystallization kinetics of pure poly(ethylene terephthalate) (PET) and chain—extended modified PET using DSC at various cooling rates. Through comparing Avrami, Ozawa, and Mo methods, the Mo method was found most effective in describing non—isothermal crystallization. The kinetic parameter F(T) indicated that pure PET crystallized faster than modified PET due to reduced chain mobility in the latter. A positive correlation between F(T) and relative crystallinity was established, showing higher cooling rates accelerate crystallinity development. The E44—modified PET had minimal impact on crystallization kinetics, making E44 a promising modifier. These findings advance the understanding of PET crystallization, and the Mo method serves as a robust framework for related studies, promoting polymer kinetics and opening new avenues for material innovation.

Promoting Form II-Form I Phase Transition of Polybutene-1 by Constantly Alternative Annealing

2025-06-19

Tangguo Liu , Xiangyang Li , Sheng-Hua Lu +3 more | Chinese Journal of Polymer Science

Phase Behavior of Reversibly Bonding Polymer Blends

2025-06-18

Christopher Balzer , Puck Springintveld , Glenn H. Fredrickson | Macromolecules

Thermodynamic origin of multistep polymer crystallization

2025-06-16

NULL AUTHOR_ID | Physical Review Letters

Water Solubility of Aliphatic Unsubstituted Polyethers

2025-06-15

Przemysław Kubisa | Macromolecular Chemistry and Physics

Abstract Water solubility of aliphatic unsubstituted polyethers of the series [(─CH 2 ) n ─O─] m (when n = 1 polymer is a polyacetal) exhibits unusual behavior when solubility in … Abstract Water solubility of aliphatic unsubstituted polyethers of the series [(─CH 2 ) n ─O─] m (when n = 1 polymer is a polyacetal) exhibits unusual behavior when solubility in water is concerned. When n = 2 [polyoxyethylene, poly(ethylene oxide), abbreviated as POE] polymers are very well soluble in water, when, however, n = 1 (polyoxymethylene, polyformaldehyde, abbreviated as POM), n = 3 (polyoxypropylene, polyoxetane, abbreviated as POX) or n = 4 (polyoxybutylene, polytetrahydrofuran, abbreviated as PTHF) they become water insoluble. Such behavior does not fit into the general rule according to which the higher the O/C ratio the better the water solubility. This counterintuitive property has been analyzed for polyoxymethylene‐polyoxyethylene pair. Earlier hypotheses explained the high water solubility of polyoxyethylene by the good fit between distances separating oxygen atoms in polyoxyethylene and the 3D structure of water while more recently it has been postulated that the observed effect is due to a much higher negative charge of oxygen in polyoxyethylene than in polyoxymethylene. Other possible factors that could also explain insolubility in the water of higher cyclic polyethers are not considered. In the present minireview, the available information concerning polyoxymethylene‐polyoxyethylene is briefly, presented and a discussion of whether they may be extended to polyoxypropylene and polyoxybutylene is included.

Morphology‐Controlled Rheological and Non‐Isothermal Crystallization Behaviors in Immiscible Polypropylene/High Density Polyethylene Blends

2025-06-15

Ke Zhan , Pixiang Wang , Xueqi Wang +6 more | Macromolecular Chemistry and Physics

ABSTRACT Understanding the correlation between morphology and the fundamental behavior of blends is crucial for tailoring their properties. This study investigated the effects of phase morphology on mechanical performance, rheology, … ABSTRACT Understanding the correlation between morphology and the fundamental behavior of blends is crucial for tailoring their properties. This study investigated the effects of phase morphology on mechanical performance, rheology, and non‐isothermal crystallization kinetics of immiscible polypropylene (PP)/high‐density polyethylene (HDPE) blends. Nanometer‐scale HDPE phases dispersed within PP, co‐continuous phases, and micrometer‐scale PP phases dispersed within HDPE were formed at 75/25, 50/50, and 25/75 PP/HDPE weight ratios, respectively. Mechanical results indicated that the co‐continuous morphology dissipated energy more efficiently than the matrix‐dispersed morphology. Rheological results showed that nanometer‐scale dispersion significantly enhanced the blend elastic modulus through the restriction effect at the interfaces. Non‐isothermal crystallization kinetics were analyzed using Jeziorny‐modified Avrami, Ozawa, Mo, and Kissinger models. Due to HDPE's heterogeneous nucleation effect, the crystallization temperature of PP was elevated, and the crystallization rate of the blend also increased with higher HDPE content. Furthermore, the blend with the 25/75 PP/HDPE exhibited a higher crystallization rate than neat HDPE, as the interfacial boundaries facilitated the alignment of HDPE chains. The higher crystallization activation energy calculated in the 75/25 PP/HDPE blend suggested that nanometer‐scale dispersion imposed a more significant restriction on crystal growth compared to micrometer‐scale dispersion.

Melting and Crystallization of Metallocene Polypropylenes

2025-06-15

Ming‐Li Sun , Jingqing Li , Xinle Li +3 more | Macromolecular Chemistry and Physics

ABSTRACT The melting and crystallization behaviors of metallocene polypropylene (mPP) were investigated using simultaneous synchrotron radiation small‐angle X‐ray scattering (SAXS) and wide‐angle X‐ray scattering (WAXS) techniques in this work. It … ABSTRACT The melting and crystallization behaviors of metallocene polypropylene (mPP) were investigated using simultaneous synchrotron radiation small‐angle X‐ray scattering (SAXS) and wide‐angle X‐ray scattering (WAXS) techniques in this work. It was found that both γ and α forms can be detected after crystallization from the melt at atmospheric pressure. The in situ simultaneous SAXS/WAXS investigations displayed that the γ form melts faster than the α form before heating to 160°C and more slowly after heating to 160°C during the melting of the mPP after isothermal crystallization. Both of the crystals form simultaneously during non‐isothermal crystallization, but they crystallize in different ways during isothermal crystallization. The evolution of SAXS results, including the scattering intensity and structure‐related q value, indicates a possible segment cluster aggregation in the mPP. Therefore, a possible crystallization process was proposed to understand the formation of the γ crystal in mPP.

Ultrahigh-Strain-Rate Mechanical Properties of Polystyrene near the Glass Transition Temperature

2025-06-13

Anuraag Gangineri Padmanaban , Takumi Uchiyama , Jonathan P. Rothstein +2 more | Applied Sciences

Elastoplastic and tribological characteristics of polystyrene are investigated as a model glassy polymer at the ultrahigh-strain rate (>106 s −1) through the temperature-controlled laser-induced particle impact testing (LIPIT) technique. Polystyrene … Elastoplastic and tribological characteristics of polystyrene are investigated as a model glassy polymer at the ultrahigh-strain rate (>106 s −1) through the temperature-controlled laser-induced particle impact testing (LIPIT) technique. Polystyrene (PS) microparticles with a diameter of 44 µm are subjected to collisions on a rigid surface at speeds ranging from 200 to 600 m s−1, while the temperature is systematically varied between room temperature and 140 °C. Utilizing the flight path and rebound motion measured from 45-degree angled LIPIT experiments, the coefficients of restitution and dynamic friction are quantified with vectorial analysis. The onset of inelasticity can be possible at a temperature substantially lower than Tg due to the early onset of crazing dominance. While temperature- and velocity-dependent coefficients of friction suggest that the activated surface of PS can facilitate the consolidation of PS microparticles, the enhancement effect is expected more profoundly when the temperature exceeds the glass transition temperature. The microscopic ballistic approach with controlled temperature demonstrates its capability of systematically evaluating the temperature effects on various inelastic deformation mechanisms of polymers at the ultrahigh-strain-rate regime.

New Insight into the Microstructure Changes and Molecular Mobility of Polyamides Exposed to H2S Scavengers

2025-06-12

Marina Perassoli de Lazari , Antonio Henrique Monteiro da Fonseca Thomé da Silva , Rodrigo Henrique dos Santos Garcia +7 more | Polymers

Polyamides (PAs) are widely used as barrier materials in offshore oil and gas (O&G) equipment due to their mechanical strength and chemical resistance. However, long-term exposure to hydrogen sulfide scavengers … Polyamides (PAs) are widely used as barrier materials in offshore oil and gas (O&G) equipment due to their mechanical strength and chemical resistance. However, long-term exposure to hydrogen sulfide scavengers (H2S-SCVs) may significantly affect their physicochemical properties. Previous studies using thermal analysis and 1H time-domain NMR (1H TD-NMR) suggest that ethoxylated H2S-SCVs impose molecular constraints, increasing the glass transition temperature (Tg) and reducing chain mobility above Tg. The present study builds upon these findings using a multi-technique analytical approach, including FTIR, Raman, 1H DQ-TD-NMR, and 13C solid-state NMR (ssNMR), to provide a more comprehensive understanding of the molecular alterations in PA materials. The results clearly demonstrate that H2S-SCV exposure leads to the progressive exudation of plasticizers from the PA matrix. This plasticizer loss is a key factor contributing to the observed shift in Tg and the reduction in molecular mobility. 1H DQ-TD-NMR data confirmed an increase in the density of dynamically constrained chains over time and allowed for the characterization of heterogeneity in these constraints throughout the PA matrix. Moreover, 13C ssNMR spectra revealed the presence of immobilized H2S-SCV chemical groups within the polymer matrix, strongly supporting the early statement that the mobility constraints observed in 1H DQ-TD-NMR are associated with the formation of crosslinks induced by the H2S-SCV: H2S-SCV acts as a crosslinking agent. Taken together, our findings indicate that both plasticizer loss and H2S-SCV-induced crosslinking contribute significantly to the microstructural evolution of PAs when exposed to ethoxylated H2S-SCVs, offering important insights into their degradation mechanisms and long-term behavior in aggressive operational environments.

Thermal Strain and Microstrain in a Polymorphic Schiff Base: Routes to Thermosalience

2025-06-12

Teodoro Klaser , Marko Jaklin , Jasminka Popović +2 more | Molecules

We present a comprehensive structural and thermomechanical investigation of N-salicylideneaniline, a Schiff base derivative that exhibits remarkable thermosalient phase transition behavior. By combining variable-temperature X-ray powder diffraction (VT-XRPD), differential scanning … We present a comprehensive structural and thermomechanical investigation of N-salicylideneaniline, a Schiff base derivative that exhibits remarkable thermosalient phase transition behavior. By combining variable-temperature X-ray powder diffraction (VT-XRPD), differential scanning calorimetry (DSC), hot-stage microscopy, and Hirshfeld surface analysis, we reveal two distinct thermosalient mechanisms operating in different polymorphic forms. Form I displays pronounced anisotropic thermal expansion with negative strain along a principal axis, culminating in a sudden and explosive phase transition into Form IV. In contrast, Form III transforms more gradually through a microstrain accumulation mechanism. Fingerprint plots and contact evolution from Hirshfeld surface analysis further support this dual-mechanism model. These insights highlight the importance of integrating macro- and microscale structural descriptors to fully capture the mechanical behavior of responsive molecular solids. The findings not only enhance the fundamental understanding of thermosalience but also inform the rational design of functional materials for actuating and sensing applications.

The Role of Wax Origin in Modifying Ultra‐High Molecular Weight Polyethylene: Structure and Properties

2025-06-11

S. N. Danilova , A. V. Okoneshnikova , N. N. Lazareva +3 more | Journal of Applied Polymer Science

ABSTRACT This study reveals previously unexplored effects of emulsion wax and beeswax on the structural and performance characteristics of ultra‐high molecular weight polyethylene (UHMWPE). It was found that composites filled … ABSTRACT This study reveals previously unexplored effects of emulsion wax and beeswax on the structural and performance characteristics of ultra‐high molecular weight polyethylene (UHMWPE). It was found that composites filled with beeswax UHMWPE‐composites exhibit a 50% increase in tensile strength, a 45% increase in relative elongation, a 58% increase in compressive strength, and a 6‐fold improvement in wear resistance relative to the origin polymer. In contrast, emulsion wax reduces the coefficient of friction by 57% compared to the initial polymer. The study also evaluated the influence of these waxes on the polymer structure formation during processing. It was demonstrated that the incorporation of both waxes promotes the formation of spherulite‐like structures, indicating enhanced mobility of polymer macromolecules during hot pressing due to the plasticizing effect of the waxes and the facilitation of orientation processes. When emulsion wax was added, the formation of elongated fibrils was observed, suggesting polymer plasticization. The addition of wax was found to reduce the extent of tribochemical processes and inhibit tribooxidation of the polymer, which is attributed to the lubrication of adjacent surfaces by the wax in the friction zone. The novelty of this work lies in the application of waxes of varying origin as modifiers for UHMWPE, where beeswax enhances strength, elasticity, and wear resistance, while emulsion wax significantly reduces the coefficient of friction of coefficient.

Optimizing Adhesion and Thermal Properties of <scp>PBAT</scp>‐Based Hot‐Melt Adhesives via Tailored Side‐Chain Architectures

2025-06-09

Hsu‐I Mao , Tung W. Chan , Hung‐Ju Yen +5 more | Journal of Applied Polymer Science

ABSTRACT This study explores the optimization of adhesion and thermal properties of poly(butylene adipate‐co‐terephthalate) (PBAT)‐based hot‐melt adhesives through tailored side‐chain architectures. PBAT copolymers were synthesized via melt polycondensation with 2‐methyl‐1,3‐propanediol … ABSTRACT This study explores the optimization of adhesion and thermal properties of poly(butylene adipate‐co‐terephthalate) (PBAT)‐based hot‐melt adhesives through tailored side‐chain architectures. PBAT copolymers were synthesized via melt polycondensation with 2‐methyl‐1,3‐propanediol (MPO) and neopentyl glycol (NPG) as comonomers to enhance adhesion performance for polyester fabric lamination. Structural characterization by 1 H‐NMR and FT‐IR confirmed successful incorporation, while DSC revealed a reduction in melting temperature (Tm) from 134.3°C to 95.4°C and a decrease in crystallization temperature (Tc) with increasing MPO/NPG content. TGA demonstrated high thermal stability, with T d‐5% ranging from 350.5°C to 362.5°C. Mechanical testing showed enhanced flexibility, decreasing Shore D hardness from 24.7 to 17.3 at 30 mol% modification. Rheological analysis indicated improved melt flow and shear‐thinning behavior, facilitating processing. T‐peel strength tests significantly increased, reaching 101.20 N/25 mm for PBAT‐N20 at Tm + 15°C, compared to 35.64 N/25 mm for neat PBAT. Water contact angle measurements confirmed increased hydrophobicity, rising from 62.89° to 74.80°, contributing to improved hydrolysis resistance. These findings highlight the effectiveness of side‐chain engineering in fine‐tuning PBAT‐based adhesives, achieving an optimal balance of adhesion strength, flexibility, and durability for high‐performance textile applications.

High-value recycling of ultrahigh molecular weight polyethylene via pulse vibration molding

2025-06-01

Shuo Gao , Wenqiang Yan , Cheng Wang +2 more | Polymer

Structural Evolution and Cavitation of Highly Melt-Stretched Isotactic Polypropylene: Effect of Entanglement Density

2025-06-01

Jian-Wei Zhou , Lu-Feng Deng , Jie Zhang +5 more | Polymer

The influence of reserved shish crystals on the structural evolution of ultra-high molecular weight polyethylene films with molecular weights in the tens of millions during the thermal stretching process

2025-06-01

Zihao Gao , Yeshun Zhong , C.F. Xing +2 more | Polymer