Compatibility and Piezoelectriaity in Polymer Blends: Copoly(vinylidene fluoride-trifluoroethylene)/ Poly(methyl m e t hacrylate) System

Abstract

Investigations on the compatibility and piezoelectric behavior depending on the conformational changes in copoly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) crystals were carried out in the polymer blends of P (VDF-TrFE)/poly(methyl methacrylate) (PMMA) system. From the thermodynamic treatment, the interaction parameters, X12, for the pair is found to be -0.329uat 150°C, indicating that the system is compatible as well as poly(vinylidene fluoride) /PMMA system. The results from X-ray diffraction, DSC, infrared spectra and TSC measurements show that the ferroelectricity is observed even in P(VDF-TrFE)/PMMA blends at the weight fraction of P(VDF-TrFE) higher than 65% with the crystal form corresponding to the form I in poly(vinylidene fluoride). According to the analyses of IR spectra and DSC as well as the piezoelectric behavior, it is considered that the polar crystals of the all trans conformation are decrystallized less efficiently due to the weaker interaction with the metoxy carbonyl group in PMMA, compared with the nonpolar crystals of the gauche conformation.