Abstract:

The non⁃isothermal crystallization behavior and crystal structure of poly（vinylidene fluoride） （PVDF）/poly（methyl methacrylate） （PMMA） blends were investigated at different cooling rates using differential scanning calorimeter and X⁃ray diffractometer， and their non⁃isothermal crystallization kinetics were studied using the Jeziorny’s equation and Mo’s method. The results indicated that a high mass ratio of PVDF to PMMA （6/4 and 5/5） completely inhibited the crystallization of PVDF. For the crystallizable blending samples at mass ratios of PVDF to PMMA of 9/1， 8/2， and 7/3， their crystallization temperature increased at first and then tended to decrease with an increase in the proportion of PMMA. However， their crystallization rate increased slightly at first and then decreased. A small amount of PMMA could generate a heterogeneous nucleation to promote the crystallization of the PVDF domain in the blends， whereas a large amount of PMMA evidently hindered the molecular rearrangement of PVDF and inhibited its crystallization. The addition of PMMA promoted the crystal structure transform of the PVDF phase to lower dimensions. The crystal structure of the PVDF phase was mainly the α⁃form crystal and was not influenced by the increase of PMMA content. This resulted in an increase at first and then a decrease in the degree of crystallinity.

Key words: poly（vinylidene fluoride）, poly（methyl methacrylate）, crystallinity, crystal form, non?isothermal crystallization kinetics