端环氧基聚苯乙烯低聚物增韧改性环氧树脂

Study on the epoxy-terminated polystyrene oligomer toughening epoxy resin

以正丁基锂引发苯乙烯进行阴离子聚合,并用少量甲基丙烯酸缩水甘油酯进行终端共聚,制得端环氧基聚苯乙烯低聚物（PSG）,并将PSG用于环氧/酸酐树脂体系的增韧改性。采用GPC和FTIR对PSG的分子质量及分子结构进行了表征。采用简支梁冲击试验机、万能试验机和热变形-维卡软化点温度测定仪及电镜分析研究了树脂浇铸体及复合材料的力学性能和耐热性。结果表明,当PSG的分子质量为3 500~4 900,添加质量分数为2%~7%时,冲击韧性由未改性环氧树脂的16.4 k J/m^2提升至31.1~39.8 k J/m^2,提高了89.6%~143%。同时,PSG改性环氧/酸酐树脂体系保持了良好的力学强度与耐热性。

The epoxy-terminated polystyrene oligomer （PSG） was prepared by anionic polymerization of styrene initiated with n- butyl lithium and terminal eopolymerization with a small amount of glycidyl methacrylate. The epoxy/anhydride system was toughened by PSG. The molecular weight and structure of PSG were characterized by GPC and FTIR. The mechanical properties and heat resistance of epoxy castings and composites modified by PSG were investigated by charpy impact test machine, universal testing maehine, heat distortion vieat softening temperature tester and electron microscope analysis. The results indicated that the neat epoxy showed brittle fracture. The modified epoxy resin showed ductile fracture and the fracture was rougher and more faults. The impact strength of modified epoxy resin was increased by 31.1-39.8 kJ/m^2 from 16.4 kJ/m^2 of neat epoxy resin and was increased by 89.6%- 143% when molecular weight of PSG was 3 500-4 900 and the adding amount of 2%-7%. The mechanical strength and heat resistance of PSG modified epoxy/anhydride system were maintained well.