Hits:

Indexed by:期刊论文

Date of Publication:2015-02-15

Journal:JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS

Included Journals:SCIE、EI、Scopus

Volume:53

Issue:4

Page Number:253-261

ISSN No.:0887-6266

Key Words:combinatorial method; crystal structures; crystallization; orientation; poly(vinylidene fluoride); spherulite; structural characterization; temperature dependence

Abstract:Temperature dependences of spherulite morphology and crystal orientation of poly(vinylidene fluoride) (PVDF) were systematically investigated via a combinatorial method. The method created a temperature gradient ranging from 130 to 200 degrees C. Results show that the preferential orientation of the crystallites changes with the crystallization temperature. The crystallization at 169 degrees C gives the most highly developed crystalline state of PVDF crystalline form II ( form), in which the spherulite size is maximal, and the crystallite sizes are also the longest, about 200 nm along the b axes. Besides, the a-axis is almost parallel to the film normal. It indicates that the crystallization rate is the highest in the b-axis direction. The perferential orientation at higher temperatures may be attributed to the confined 2D growth of the PVDF spherulites in the thin film, whereas the spherulites grow in the 3D mode at lower temperatures. The crystallization behavior revealed in the method is consistent with the results of melt isothermal crystallization experiments. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 253-261