Download or read book Crystallization Kinetics of Poly ethylene Oxide written by Frances H. Segouin and published by . This book was released on 1994 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The three main goals of this project are to determine the molecular weight dependence of polyethylene oxide) on the 1) morphology of crystalline material, as seen with the polarizing light microscope, 2) nucleation of the crystalline phase, as demonstrated with an annealing study, and 3) parameters of a mathematical model for crystallization kinetics. Bulk crystallization kinetics of polyethylene oxide) from the melt have been studied for a large molecular weight range, 1500 g/mol to 7,000,000 g/mol. The effects of molecular weight and cooling rate on the width and degree of supercooling of DSC crystallization exotherms have been studied to determine the type of nucleation involved and to determine the relationship between the DSC signals and the morphology of a crystalline sample. As the molecular weight increases, at a cooling rate of twenty degrees per minute, the width-at-half- height of the exothermic DSC peak decreases from seven degrees to approximately three degrees for the low molecular weight samples and increases from three to seven degrees for the high molecular weight samples. The degree of supercooling at which the peaks reach a maximum generally increases from twelve degrees Celsius to above twenty degrees Celsius. The slower the cooling rate the narrower the width at half height of the crystallization peak and the lower the degree of supercooling at the maximum point of the crystallization exotherms. For all of the molecular weight samples, the crystallization peak temperatures increase in the range of one to ten degrees of supercooling from a one-degree-per-minute cooling rate to a twenty degrees-per-minute cooling rate. The average width-at-half-height increases from three to six- degrees Celsius from the one degree-per-minute cooling rate experiment to the twenty degreesper- minute cooling rate experiment. The morphology of the samples varied from a coarse non-interconnected lamellae formation below the critical molecular weight to an interconnected lamellae formation, also known as a spherulite, above the critical molecular weight. The critical molecular weight for polyethylene oxide) is 3400 g/mol. Based on the expression for the linear crystal growth rate, reported by Cheng et al.1, a mathematical model was created to model the DSC crystallization curves. This model, which incorporates heat transfer effects, can model the width and shape of the DSC curves, but the degree of supercooling that the model predicts is generally smaller than the experimental degree of supercooling. While modeling the DSC crystallization curves, it was found that the activation energy for reptation motion, U*, has less of an effect on the model crystallization curves than does the surface energy term, Kg, of the Cheng growth rate expression."--Abstract.
Download or read book Crystallization Kinetics and Crystal Morphology in Thin Poly ethylene Oxide Films written by Michael V. Massa and published by . This book was released on 2002 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystallization Kinetics of Polyethylene Oxide written by Mohammad Sabir and published by . This book was released on 1967 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kinetics of crystallization in poly ethylene oxide written by Agostinho Scigliano and published by . This book was released on 1971 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystallization of Polymers Volume 2 Kinetics and Mechanisms written by Leo Mandelkern and published by Cambridge University Press. This book was released on 2004-09-30 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Crystallization of Polymers, 2nd Edition, Leo Mandelkern provides a self-contained, comprehensive, and up-to-date treatment of polymer crystallization. Volume 2 of this edition provides an authoritative account of the kinetics and mechanisms of polymer crystallization, building from the equilibrium concepts presented in volume 1. As crystalline polymers rarely, if ever, achieve their equilibrium state, this books serves as a bridge between equilibrium concepts and the state that is finally achieved. With a comprehensive treatment of the surrounding theories and experimental results from simple to complex polymer systems, this book will be an invaluable reference work for all chemists, physicists and materials scientists working in the area of polymer crystallization.
Download or read book Relationships Between Morphological Characteristics Kinetics of Crystallization and Crystallization Temperature for the Dilute Solution Crystallization of Poly ethylene Oxide written by Elaine Rose Williams and published by . This book was released on 1971 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Pressure on the Crystallization Kinetics of Poly ethylene Terephthalate written by and published by . This book was released on 1994 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystallization Crystal Orientation and Morphology of Poly ethylene Oxide Under One Dimensional Defect free Confinement on the Nanoscale written by Ming-Siao Hsiao and published by . This book was released on 2009 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: "One dimensionally (1D) confined crystallization based on semicrystalline diblock copolymers has been widely investigated for twenty years. Highly orientated lamellar samples, after large amplitude oscillation shear, provide the typical 1D confined environment to investigate crystallization behavior, such as crystal orientation and crystallization kinetics. However, inevitable defect generation, such as edge and screw dislocations during mechanical shear lead to "cross-talking" between grain boundaries and significantly affect the ideal 1D confinement crystallization kinetics by releasing the confinement. Meanwhile, the mechanism of the origin of specific crystal orientations (parallel or perpendicular) within the 1D confinement is still under debate. In this research, PS-b-PEO single crystals composed of one PEO nano-layer sandwiched by two PS glassy layers on the nanoscale were chosen as a template to investigate polymer crystallization in a 1D defect-free nanoscale confinement. Since the TgPS is higher than the TmPEO in such a "sandwich" lamellar structure, the PEO single crystal can be melted while keeping the PS layer in the vitrified state. The PEO blocks can be recrystallized between the two confining, glassy PS nano-layers at different re-crystallization temperatures, Trx, and monitored for different recrystallization behavior using electron diffraction (ED). Results indicate that the PEO block does not recrystallize until Trx = -5°C, the limit of homogeneous nucleation. This observation confirms PEO recrystallization takes place in a defect-free confinement. Next, a puzzling ED pattern taken from PEO microcrystals grown at Trx>-5°C via self-seeding was analyzed to be the result of the specific interaction between tethered PEO blocks having monoclinic symmetry and the glassy PS substrate. Two different inclined PEO microcrystals having an orthogonal relationship truly coexisting in the lamellar confinement during self-seeding were found. Furthermore, PS-b-PEO single crystal mats provide a template for investigating how confined dimension (dPEO) and reduced tethering density (PEO) affect the Trx dependent crystal orientation. The results show that a dramatic change of PEO crystal orientation from parallel to perpendicular with respect to the PS lamellar plane within 1°C when Trx is close to the limit of PEO homogeneous nucleation. The crystal orientation may have resulted from a competition of the PEO segmental orientation near the PS and PEO interfaces, which is determined by reduced tethering density with anisotropies of the overall chain conformation; and density fluctuations of the PEO melt due to the confinement of the PS layers. This study hopes to provide a universal principle to answer the debate over 1D confined crystallization. Finally, the interplay of three factors (lamellar confined volume (V), confined dimension (dPEO) and reduced tethering density (PEO) determine the final onset temperature of the sharp crystal orientation change, and the distribution of these Tonset values are over 31°C."--Abstract.
Download or read book A Study of the Crystallization Kinetics of Poly ethylene Terephthalate written by Kenneth Gordon Mayhan and published by . This book was released on 1965 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystallization Kinetics of Polyethylene written by Allan Booth and published by . This book was released on 1969 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystallization of Polymers written by Marcel Dosière and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the discovery that polymer single crystals are composed of chain folded macromolecules in 1957, the crystallization of polymers has attracted considerable interest and still provides fascinating and fruitful areas of research. Only a few books have been fully devoted to the crystallization of polymers in the past. This book contains the proceedings of the NATO ARW devoted to the `Crystallization of Polymers' which took place in September 1992 at the University of Mons-Hainaut (Belgium). In view of the variety of papers devoted to the crystallization of polymers, this book will be used in the next few years as a reference book for scientists concerned in the field of polymer physical chemistry. Crystallization of Polymers is mainly devoted to the experimental and theoretical study of the crystallization of synthetic polymers. As a kinetic study of the growth of polymer crystals should always be preceded by a morphological or a structural investigation, the structure, the morphology of polymer crystals and more particularly the lamellar and supralamellar organizations, as well as the nature of the crystal amorphous interface are reviewed and discussed.
Download or read book Crystallization Kinetics of Polyethylene Terephthalate written by Leonard Henry Palys and published by . This book was released on 1977 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Molecular Weight and Concentration on the Crystallization Kinetics of Polyethylene N hexadecane System written by Chih-Chang Chu and published by . This book was released on 1976 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crystallization in Multiphase Polymer Systems written by Sabu Thomas and published by Elsevier. This book was released on 2017-09-15 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystallization in Multiphase Polymer Systems is the first book that explains in depth the crystallization behavior of multiphase polymer systems. Polymeric structures are more complex in nature than other material structures due to their significant structural disorder. Most of the polymers used today are semicrystalline, and the subject of crystallization is still one of the major issues relating to the performance of semicrystalline polymers in the modern polymer industry. The study of the crystallization processes, crystalline morphologies and other phase transitions is of great significance for the understanding the structure-property relationships of these systems. Crystallization in block copolymers, miscible blends, immiscible blends, and polymer composites and nanocomposites is thoroughly discussed and represents the core coverage of this book. The book critically analyzes the kinetics of nucleation and growth process of the crystalline phases in multi-component polymer systems in different length scales, from macro to nanoscale. Various experimental techniques used for the characterization of polymer crystallization process are discussed. Written by experts in the field of polymer crystallization, this book is a unique source and enables professionals and students to understand crystallization behavior in multiphase polymer systems such as block copolymers, polymer blends, composites and nanocomposites. Covers crystallization of multiphase polymer systems, including copolymers, blends and nanocomposites Features comprehensive, detailed information about the basic research, practical applications and new developments for these polymeric materials Analyzes the kinetics of nucleation and growth process of the crystalline phases in multi-component polymer systems in different length scales, from macro to nanoscale
Download or read book Crystallization Kinetics and Polyblends of Poly ethylene Terephthalate Recycled from Post consumer Beverage Bottles written by Peming Peter Hsu and published by . This book was released on 1991 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Poly Ethylene Oxide written by F.E. Jr. Bailey and published by Elsevier. This book was released on 2012-12-02 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Poly (ethylene oxide) discusses the molecular characteristics of a crystalline, thermoplastic, water-soluble polymer. The book presents the preparation of ethylene oxide; the synthesis of high and low molecular weight polymer; and the complexes with acrylic and methacrylic acid polymers. The text describes the radiation crosslinking of solutions and discusses the electrical conduction of saturated organic polymers. Another topic of interest is the surface tension and density of polyethylene glycol. The section that follows describes the reactivity and comonomer structure of copolymers. The book will provide valuable insights for chemists, students, and researchers in the field of organic chemistry.
Download or read book Crystallization Kinetics and Morphological Studies of High density Polyethylene written by Edward F.-H. (Feng-Hwa) Chu and published by . This book was released on 1983 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
