甲基丙烯酸甲酯在聚偏氟乙烯膜上的辐照接枝

Irradiation Grafting Reaction of PMMA onto PVDF Film

采用电子加速器(EB)预辐照接枝的方法,在聚偏氟乙烯(PVDF)膜上接枝甲基丙烯酸甲酯(MMA),制备了PVDF-g-PMMA膜。研究了辐照剂量、单体浓度、反应温度、反应时间以及溶剂等因素对接枝率的影响规律。结果表明,接枝率随辐照剂量的增大而增加;反应初期接枝率随着单体质量分数的增大迅速增加,当单体质量分数达40%时,增加缓慢;单体质量分数达70%时,接枝率最高;从40℃开始接枝率缓慢上升,至60℃时陡增,之后接枝率基本不变;醇类是接枝反应很好的溶剂。用FT-IR、DSC分析了接枝物的组成及热性能。接枝膜成分为PVDF-g-PMMA共聚物,接枝膜在117℃处出现Tg峰,随着接枝率的增加该峰越来越明显,说明发生了接枝反应。随着接枝率的增加,熔融峰左移并最终消失,说明PMMA的接枝破坏了原PVDF膜的结晶性。吸液率随着浸泡时间的增加而增大,PVDF接枝膜达到的最大吸液率为290%,所需要的时间比原PVDF膜长。接枝率为50%的PVDF膜的离子电导率为6.0×10-3S/cm,吸液率达290%,MMA的接枝改善了PVDF电解质膜的电学性能。

Poly（ methyl methacrylate） （PMMA） was grafted onto poly（ vinylidine fluoride） （PVDF） films preirradiated electron beam （EB）. The influence of the radiation dosage, monomer concentration, reaction temperature and time as well as solvent on the grafting reaction was studied. Results showed that grafting rate increased with the radiation doseage. With the increase of monomer concentration, the grafting rate increased quickly at the preliminary stage and increased slowly above 40% and then reached a maximum when the monomer concentration was 70%. Grafting rate increased slowly below 40 ℃, and increased fast at 60 ℃,and then remained unchanged. Alcohols were effective solvents for the graft polymerization. The composition of the grafted film was analyzed using FT-IR, and the thermal performance of the grafted film was characterized by DSC. The FT-IR showed that the grafted film was a PVDF-g-PMMA copolymer. A thermal transition appeared at 117 ℃ and became more marked with the grafting yield. The melting peak moved to the left and disappeared finally with the grafting rate, which proved the grafting of PMMA broke down the PVDF film＇s crystallinity. At the DOG of 50%, the liquid uptake volume was 290% and the conductivity was 6.0 × 10^-3 S/cm.