Crystallization of poly(vinylidene fluoride) in blends with poly(methyl methacrylate-co-methacrylic acid) copolymers

A series of poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MAA) random copolymers ranging in MAA content from 0-15 mol% is synthesized and blended with poly(vinylidene fluoride) (PVDF). Using infrared spectroscopy, it is observed that the absorption bands attributed to hydrogen-bonded carbonyl groups increase in intensity as the amount of MAA in the copolymer increases. In DSC analysis, the crystallization temperature of the PVDF in the blend initially decreases by ca. 12 °C with MAA contents ranging from 0 to 5.5 mol%; however, a PVDF blend with a 15 mol% MAA copolymer has a crystallization temperature that is only ca. 3 °C below that of pure PVDF. Similarly, spherulitic growth rate analysis initially shows a decrease in radial growth rate for PVDF in blends with PMMA-co-MAA copolymers containing less than 5.5 mol% MAA. At higher MAA copolymer contents, the spherulitic growth rate approaches that of pure PVDF. It is concluded that the presence of the MAA comonomer in the PMMA-co-MAA copolymer initially (<5.5 mol% MAA) increases the intermolecular interactions between the copolymer and the PVDF. However, as the MAA content of the copolymer rises above 5.5 mol%, intramolecular hydrogen bonding interactions within the PMMA-co-MAA copolymer cause the copolymer to be less compatible with PVDF. Poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MAA) copolymers are synthesized and blended with poly(vinylidene fluoride) (PVDF). It is observed that the crystallization rate of PVDF is reduced when the MAA content is <5.5 mol% in the copolymer due to enhanced intermolecular interactions. At higher MAA contents, the growth of the PVDF crystallites in the blend approach that of pure PVDF.