Melting and Crystallization of Poly(vinylidene fluoride) in the Blend with Poly(methyl methacrylate) under High Pressure

Abstract

Melting and crystallization of poly(vinylidene fluoride) (PVF2) in the blend with poly(methyl methacrylate) (PMMA) was studied by differential thermal analysis (DTA) under high pressures up to 350 MPa. Characterization of the pressure-crystallized blend sample with different weight fractions of PVF2 between 1.0 and 0.5 was performed at atmospheric pressure by DTA, differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD) measurements. Pressure dependence of the melting temperature of form II of PVF2 in the blend between 1.0 and 0.6 of the weight fraction was almost the same (about 0.34 K MPa−1). The WAXD patterns and thermal analysis of the blend show that form I of PVF2 crystallizes at lower pressure with increasing PMMA content in the sample. DTA and DSC at atmospheric pressure show that the high pressure crystallization of PVF2 in the blend with PMMA results in the formation of form I which melts at lower temperature than form II.