两亲性嵌段共聚物聚己内酯-聚二甲基硅氧烷-聚己内酯增韧氰酸树脂性能研究

THE PROPERTIES OF AMPHIPHILIC BLOCK COPOLYMER POLYCAPROLACTONE-POLYDIMETHYLSILOXANE-POLYCAPROLACTONE TOUGHENED CYANATE RESIN

采用开环聚合合成聚己内酯-b-聚二甲基硅氧烷-b-聚己内酯(PCL-b-PDMS-b-PCL)两亲性三嵌段聚合物混合进氰酸酯树脂预聚体中,得到了具有纳米复合结构的氰酸酯树脂/嵌段改性混合物。氰酸酯树脂/嵌段体系的SAXS与TEM结果表明,CE/PCL-b-PDMS-b-PCL体系自组装形成50 nm～60 nm的纳米复合结构。随着嵌段含量增加,多相形态由颗粒改变至蠕虫状结构,粒子间距增大。非等温DSC固化与KIC数据结果表示,氰酸酯树脂/嵌段体系固化放热峰的温度逐渐降低,反应活性提高,并且其断裂韧性有所提高。

By the ring-opening polymerization of caprolactone,PCL-b-PDMS-b-PCL triblock amphiphilic polymer was obtained and added into the cyanate ester thermosetting resin,producing a mixture of self-assembled nanostructures.In the ester resin prepolymer,a cyanate resin/block modification mixture having a nanocomposite structure is obtained.The results of cyanate resin/block system SAXS and TEM confirm that the 50 nm^60 nm nanostructures were achieved by CE/PCL-b-PDMS-b-PCL system.The system also has a diverse morphology from particles to worm-like structures as the block polymer content increases.Meanwhile,the average distance between neighboring microdomains increases.The mechanism of the the CE/PCL-PDMS-PCL is self-assembling.By non-isothermal DSC curing and critical stress intensity factor(K IC)value,the block-modified resin is 25℃~50℃ahead of the exothermic peak of the unmodified CE resin,indicating that the reactivity of blends system is improved.The K IC of the 20 wt%block content of CE/PCL-b-PDMS-b-PCL was 0.65,which was 97%higher than that of the unmodified CE system,demonstrating that the fracture toughness of the block-modified resin is improved.