液体聚硫橡胶增韧双酚A-苯胺型聚苯并噁嗪的研究

Liquid Polysulfide Rubber Toughening Bisphenol A-Aniline Based Polybenzoxazine

以液体聚硫橡胶(LP-3)为增韧剂,对双酚A-苯胺型苯并噁嗪(B-a)树脂进行了改性,通过核磁共振氢谱(1H-NMR)、红外光谱(FTIR)、示差扫描量热仪(DSC)对B-a与LP-3的共混和固化过程进行了研究,通过动态热机械分析仪(DMA)、弯曲和冲击实验、热失重分析仪(TGA)对固化物的机械性能和热性能进行了表征.结果表明,在共混过程中,B-a与LP-3发生了开环加成反应,加成产物的酚羟基对苯并噁嗪的开环聚合具有一定的促进作用,共混物较B-a具有更快的固化速率.当LP-3的加入量为5 wt%时,固化物的韧性就可以得到明显改善,冲击强度相比B-a固化物提高了3.4倍,而且此时的固化物具有高的储能模量(30℃时E'=3.9 GPa)、高的玻璃化转变温度(T_g=206℃)和良好的热稳定性(T_(5%)=322℃,T_(10%)=342℃),表现出最佳的综合性能.

Liquid polysulfide rubber （LP-3） was used as a toughening modifier to improve the toughness of polybenzoxazine obtained from bisphenol A-aniline based benzoxazine （B-a）. The mixing and curing processes of B-a and LP-3 were monitored by 1H-NMR, FTIR and DSC. It was found that the ring-opening addition reaction between B-a and LP-3 happened during mixing,and the resultants showed lower curing temperature and faster curing rate than the pure B-a. The thermal and mechanical properties of the cured materials with various LP-3 incorporations were measured by TGA,DMA,impacting and flexural test. The results showed that LP-3 was an effective toughener for polybenzoxazine from B-a. Materials containing LP-3 in the crossfinked network showed much better toughness than that without LP-3. With the increase of LP-3 incorporation, impacting strength increased while modulus and glass transition temperature （ Ts） decreased. When 5 wt% LP-3 was added, the impacting strength of the cured material was about 3.4 times higher than that of the polybenzoxazine from pure B-a. Simultaneously,the material at this LP-3 content retained high storage modulus （E＇= 3.9 GPa at 30 ℃） and high glass transition temperature （Ts = 206℃） with improved flexural properties and thermal stability （ T5% = 322 ℃ , T10% = 342 ℃ ）. It was concluded that LP-3 was a promising modifier for the commercial B-a resin even with small addition amount. When the amount of LP-3 was 5 wt% , the cured material owned the best overall performance.