异氰酸酯基偶联剂改性PAN基碳纤维增强聚三唑复合材料的研究

Modification of PAN-based carbon fiber reinforced polytriazole composites with isocyanate-containing coupling agent

采用异氰酸酯基偶联剂(A1)对聚丙烯腈(PAN)基碳纤维表面进行处理,制备了碳纤维增强聚三唑(PTA)复合材料;考察了偶联剂A1改性PAN基碳纤维的工艺;对比了溶剂丙酮中水分的影响。结果表明:工业丙酮为溶剂时,加入偶联剂A1缩短了PTA树脂胶液贮存期,需现配现用;偶联剂A1处理PAN基碳纤维,预处理法使T700碳纤维布/增强复合材料剪切强度提高39.2%,迁移法提高9.5%,相比用分析纯丙酮为溶剂的体系,改性效果降低;偶联剂A1在PAN基碳纤维表面生成脲类等极性化合物,增强了与树脂基体的氢键吸附,改善了复合材料的界面粘结,但工业丙酮中的水分消耗了偶联剂的作用基团,过量的杂质削弱了偶联剂与纤维的化学作用。

A carbon fiber reinforced polytriazole （PTA） composite was prepared by modifiying the surface of polyacrylonitrile （PAN）-based carbon fiber with a coupling agent （A1） containing isocyanate group. The modification process of PAN-based car- bon fiber with coupling agent A1 was investigated. The impact of the moisture content in acetone solvent was contrasted. The re- suits showed that the addition of coupling agent Al shortened the shelf life of PTA resin while using industrial acetone as a sol- vent, which should be formulated immediately before application; and the shearing strength of T700 carbon fiber cloth reinforced PTA composite can be increased by 39.2% by pretreatment method and 9.5% by migration method when the PAN-based carbon fiber was treated with coupling agent A1, which contributed the lower modification effect than analytically pure acetone; isocya- nate group in coupling agent A1 reacted with active sites on PAN-based carbon fiber surface and formed polar ureas groups which enhanced the hydrogen bonding adsorption on resin matrix and improved the interfacial adhesion of the composite, but the excess water in industrial acetone preferentially reacted with isocyanate group and the produced impurities reduced the chemical bonding between the fibers and the coupling agent.