Effects of annealing and isothermal crystallization upon crystalline forms of poly(vinylidene fluoride)

Abstract

Abstract Poly(vinylidene fluoride) exists in three crystalline forms. Optimum conditions for preparing form III were established by infrared spectroscopy, differential scanning calorimetry, and x‐ray diffraction measurements. Form III is easily obtained by annealing mats of solution‐grown crystals of form II at 175–185°C and is also preferentially formed by isothermal crystallization from the melt between 165 and 175°C. Below 165° crystallization of form II is favored. The melting point of form III is higher than that of form II.