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1.
We investigated the effect of ethylene and vinyl acetate (20/80 mole ratio) copolymer (EVAc80) content in poly(vinylidene
fluoride) (PVDF/EVAc80) blends and also varying isothermal crystallization temperatures on the crystalline structure and morphology,
and surface topography using different spectroscopic and microscopic techniques. As crystallization temperature increases
for the same blend composition, the lamellar splay type spherulite is changed to the concentric ring-banded spherulite, and
then to the spiral-ringed spherulite with further increasing temperature. With increasing EVAc80 content in the PVDF/EVAc80
blends, the temperature range, where spiral-ringed spherulites and lamellar splay typeγ-spherulites are present predominantly, becomes much broader. Furthermore, the non-textured spherulite was observed more at
highest crystallization temperature with increasing EVAc80 content. The band spacing between bright and dark zone and periodicity
between ridge and valley increase with increasing amorphous EVAc80 content. 相似文献
2.
Phase behavior and spinodal phase separation kinetics in binary blends of a random copolymer of vinylidene fluoride and trifluoroethylene
(75/25) [P(VDF/TrFE)] and poly(1,4-butylene adipate) (PBA) have been investigated by means of optical microscopic observation
and time-resolved light scattering. The blends exhibited a typical lower critical solution temperature (LCST)∼34 °C above
the melting temperature of the P(VDF/TrFE) crystals over the entire blend composition range. P(VDF/TrFE) and PBA were totally
miscible in the temperature gap between the melting point of P(VDF/TrFE) and the LCST. Temperature jump experiments of the
3/7 P(VDF/TrFE)/PBA blend were carried out on a light-scattering apparatus from a single-phase melt state (180 °C) to a two-phase
region (205∼215 °C). Since the late stage of spinodal decomposition (SD) is prevalent in the 3/7 blend, SD was analyzed using
a power law scheme. Self-similarity was preserved well in the late stage of SD in the 3/7 blend. 相似文献