Phase behavior of rapidly quenched PVDF/PMMA blends as characterized by raman spectroscopy, X-ray diffraction and thermal techniques

Although PVDF/PMMA blends have been studied extensively, the phase behavior as a function of melt quenching conditions has not been examined in detail in the past. In this paper we report our results on the isotropic blends of PVDF/PMMA quenched into ice water as well as on a casting roll set at 30 degrees C in all composition ranges. The results confirm the miscibility of this blend for all composition ranges, although at high PVDF (similar to 85%) concentration micro heterogeneities were evidenced through thermal analysis. Though pure PVDF is observed to be mostly in the a crystalline form, the addition of PMMA favors the 0 crystal structure in composition range 85/15-60140. Ice water quenching yields amorphous blends containing more than 40% PMMA and these films are deemed good candidates for rubbery state processes (between T-g and T-cc), including tenter frame biaxial stretching, where they can be oriented significantly at these low temperatures while undergoing strain induced crystallization.