Modification on crystallization of poly(vinylidene fluoride) (PVDF) by solvent extraction of poly(methyl methacrylate) (PMMA) in PVDF/PMMA blends

The crystallization modification of poly(vinylidene fluoride) (PVDF) was investigated for the blend films of PVDF and poly(methyl methacrylate) (PMMA). The mass crystallinity (X-c) and further, the beta-phase content (F-(beta))of PVDF, were studied for the asprepared blend films with different mass ratios. In addition, the variations of X-c and F-(beta) were systematically probed once the PMMA component was removed from the related blend systems. DSC, FTIR and XRD measurements all indicated that 1)X-c, F-(beta) and even the content of alpha-phase (F-(alpha)) decreased with the addition of PMMA; 2) with the extraction of PMMA, both X-c and F-(beta) increased while F(a) decreased. It is worth noting that the increase of X-c and F-(beta) depended on the relative amount of extracted PMMA (EPMMA), i.e., the more PMMA was removed, the more.c and F-(beta) increased. These results reveal the hindrance effect from the PMMA constituent to the crystallization of PVDF, and consequently, this restriction would be released when the PMMA was extracted.