ISSN:
0887-6266
Keywords:
P(VDF/TrFE) copolymer
;
phase transition
;
ferroelectric
;
crystallization
;
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
A systematic study was carried out on the effect of the crystallization temperature (Tcr), on the phase transitions presented by P(VDF/TrFE) copolymers cast from dimethylformamide (DMF) solution with molar ratios 60/40, 70/30, and 80/20. The results obtained by differential scanning calorimetry (DSC) showed that two-phase transitions are observed only when the copolymer crystallizes above a certain temperature To, and that the temperatures at which these transitions occur are reduced slightly with Tcr increase. It also was observed that when Tcr increases, the intensity of the endotherm corresponding to the lowest temperature transition is increased, whereas the one corresponding to the highest temperature transition is reduced. In order to explain these phenomena, the existence of two ferroelectric and two paraelectric phases is suggested. The conformational differences between like phases occur due to the distinct origin of each one: the best organized phase crystallizes directly from solution, whereas the least organized is the result of a solid phase transition. Wide angle x-ray diffusion (WAXD) diffractograms corroborate this hypothesis. Phase diagrams for samples crystallized below and above To have been proposed. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 403-414, 1998
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
