Crystallization of Poly(vinylidene fl uoride) in Blends with Poly(methyl methacrylate-co-methacrylic acid) Copolymers

摘要

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 fl uoride) (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 comono mer in the PMMA-co-MAA copolymer initially (<5.5 mol MAA) increases the intermolecular interactions between the copoly mer 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 copoly mer to be less compatible with PVDF.