PHASE-SEPARATION BEHAVIOR OF BLENDS OF POLY(VINYLIDENE FLUORIDE-CO-TETRAFLUOROETHYLENE) AND POLY(METHYL METHACRYLATE) BY DIFFERENTIAL SCANNING CALORIMETRY

Miscibility and phase separation were investigated in the blend of poly(vinylidene fluoride-co-tetrafluoroethylene) (P(VDF-TFE)) and poly(methyl methacrylate) (PMMA). The blends showed the single glass transition and melting point depression for all blend compositions, indicating that they are miscible. The phase separation behavior of a blend was elucidated by differential scanning calorimetry (DSC). On heating the blend samples, an endothermic peak in DSC thermogram appeared at the cloud point which was obtained from the change of optical transmittance of samples. The area under the endothermic curve was assumed to be the heat of demixing. It showed a maximum near 50 wt% of P(VDF-TFE). From the heat of demixing, the compositional dependence of interaction parameter was calculated and it was an increasing function of P (VDF-TFE) content.