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Spherulitic Structure (spherulitic + structure)
Selected AbstractsStudies on , to , phase transformations in mechanically deformed PVDF filmsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Vijayakumar R. P. Abstract PVDF cast films were drawn at different temperatures to different draw ratios at constant draw rate to understand the mechanism of , to , phase transformation during mechanical deformation. WAXD and FTIR studies were carried out to determine the formation and content of , phase in the drawn films. Lower stretch temperatures gave higher fractions of , phase. The cast PVDF films were also drawn at suitable temperatures below the PVDF ambient melting point to the draw ratio of 6.4. The highest fraction of , phase obtained in these ultra drawn films was 0.98. SALS studies carried out for films at different stretch ratios show the change in spherulitic structure with the stretching parameters and give information for the understanding of phase transformation during stretching of PVDF films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Effects of SBS on phase morphology of iPP/aPS blendsPOLYMER ENGINEERING & SCIENCE, Issue 10 2000The supermolecular structure of binary isotactic polypropylene/poly(styrene- b -butadiene- h -styrene) (iPP/SBS) and isotactic polypropylene/atactic polystyrene (iPP/aPS) compression molded blends and that of ternary iPP/aPS/SBS blends were studied by optical microscopy, scanning and transmission electron microscopy, wide-angle X-ray diffraction and differential scanning calorimetry. Nucleation, crystal growth, solidification and blend phase morphology are affected by the addition of amorphous components (SBS and aPS). As a compatiblizer in immiscible iPP/aPS blends, SBS formed interfacial layer between dispersed honeycomb-like aPS/SBS particles and the iPP matrix, thus influencing the crystallization process in iPP. The amount of SBS and aPS, and compatibilizing efficiency of SBS, determine the size of dispersed aPS, SBS, and aPS/SBS particles and, consequently, the final blend phase morphologies: well-developed spherulitic morphology, cross-hatched structure with blocks of sandwich lamellae and co-continuous morphology. The analysis of the relationship between the size of spherulites and dispersed particles gave the criterion relation, which showed that, in the case of a well-developed spherulitization, the spherulites should be about fourteen times larger than the incorporated dispersed particles; i.e. to be large enough to engulf dispersed inclusions without considerable disturbing of the spherulitic structure. [source] Spherulitic superstructure and morphology of poly(ethylene oxide),lithium perchlorate complexPOLYMER COMPOSITES, Issue 12 2008Xiaobin Huang The morphology of solid polymer electrolytes based on PEO-LiClO4 complex was investigated by polarized optical microscopy (POM). The spherulitic structure derived from POM suggested that the ion induces different spherulitic structures. An interesting turning point of salt concentration has been found. At the turning point, the complex was amorphous. The melting point, size, and growth rate of the spherulite decreased with increasing of salt concentration before the turning point and began to increase after the turning point. The multiphase structure of the complexes have been deduced and proved by X-ray diffraction. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Effect of thermomechanical history on the crystallization of poly(ether- block -amide)POLYMER ENGINEERING & SCIENCE, Issue 12 2008Bruno Tavernier The quiescent and flow-induced crystallization of a poly(ether- block -amide) is studied by means of rheo-optical methods. Both optical microscopy and small angle light scattering have been used. The multiblock copolymer has a microphase-separated structure with an order,disorder transition at 180,185°C, as measured with rheometry and SAXS. The number of nuclei, spherulitic growth rates, and the characteristic time scale for crystallization are compared with that of a polyamide of similar molar mass. For the poly(ether- block -amide),containing a majority of amide segments,the growth rates of the spherulites during quiescent crystallization are similar for the block copolymer and the homopolymer, even if the spherulitic structures are not the same. When flow is applied, the two materials behave differently. The flow increased the nucleation density in the homopolymer but not in the block copolymer. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] | ||||||||||