Liquid and solid epoxy resin were mixed. DDS was used as the curing agent and polyamic acid (PAA) was added to modify the resin matrix. Epoxy resin film was prepared using method of scraping membrane. The effects of solid-to-liquid ratio of epoxy and the amount of PAA on film forming ability, curing temperature and curing rate were studied by means of DSC, plate-wire-drawing method and FFIR. The reaction mechanism of PAA on the curing reaction of epoxy/DDS system was explored as well. The result showed that adding PAA into the resin matrix can improve the toughness of epoxy resin film, reduce the curing temperature and accelerate the curing rate. For this resin system (the mass ratio of solid epoxy to liquid epoxy was 50: 50), while the amount of PAA was 5 wt％, the initial curing temperature was descended from 175.9 ℃to 138.8 ℃ and the gel time was descended from 162 min to 46 min. The resin system was turned from high temperature system into nearly medium temperature system.%以液体环氧树脂与固体环氧树脂混配,4,4′-二氨基二苯砜(DDS)为固化剂,加入聚酰胺酸(PAA)对固液混配环氧树脂进行改性,采用刮膜法制备环氧树脂胶膜.通过DSC分析、平板拉丝法和傅里叶转换红外光谱法,研究了环氧树脂固液比、PAA用量等对环氧树脂胶膜成膜性、同化温度和同化速率的影响,并探索了PAA对环氧树脂/DDS体系固化反应的作用机理.结果表明,PAA可提高环氧树脂胶膜韧性,可降低固化温度,加快固化速度.对于环氧树脂(固/液质量比为50/50)/DDS/PAA体系,当PAA质量分数5%时,同化起始温度由未加PAA时的175.9℃下降到138.8℃,140℃时的固化凝胶时间由162 min下降到46 min,体系由高温固化变为近中温固化.
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