废弃芳纶粉末环氧化改性及其固化物性能

针对国内对位芳纶（PPTA）在实际生产中产生的低分子量PPTA粉末，探讨了一种有效回收再利用的方法。本文以低分子量PPTA为原料、环氧氯丙烷为改性剂，采用金属化/取代反应，制备了环氧氯丙烷（ECH）修饰的PPTA（PPTAGE），并通过单因素实验优化了PPTAGE合成条件。结果表明：合成条件为m(ECH）∶m(PPTA)=3∶1、NaH用量（与总投料量质量之比）0.4%、反应温度80℃、反应时间4.5h时，PPTAGE接触角最小，纤维表面能最佳。将改性前后的芳纶分别作为环氧树脂的填料，得到固化物样条，研究了PPTAGE对环氧树脂复合材料力学性能的影响。固化物力学性能研究表明，PPTAGE可以在一定程度上提高与环氧树脂基体的黏合，在添加量为1%时，复合材料的力学性能达到最佳；热重（TGA）分析表明，固化物热稳定性较PPTA/E-51有所提高；扫描电镜（SEM）测试表明，PPTAGE/E-51冲击断裂面为韧性断裂。

Epoxidation modification of waste aramid fiber powder and properties of curing products

Aiming at the high-value low-molecular-weight para-aramid (PPTA) produced from the waste material of para-aramid fiber production, an effective recycling method was discussed. Epoxy group modified PPTA(PPTAGE) was prepared with PPTA as the raw material and epichlorohydrin as the modifier using an adopting metalized/substitution reaction. The synthesis conditions of PPTAGE were optimized through single factor experiments. The results showed that the suitable synthesis conditions of PPTAGE were m(ECH)∶m(PPTA)=3∶1, the amount of NaH (the mass percentage of the materials input) was 0.4%, the reaction temperature was 80℃ and the reaction for 4.5h. The modified aramid fiber was used as the filler of the epoxy resin to obtain the cured products, and the effect of PPTAGE on the mechanical properties of the cured product was studied. The properties of the cured product indicated that the modified PPTA can improve the adhesion of PPTA to the epoxy resin matrix. When the addition amount was 1%, the mechanical properties of the cured product was the best. After adding PPTAGE, the cured product was thermal stalely. Compared with PPTA/E-51, its performance was improved. SEM test showed that the impact fracture surface of PPTAGE/E-51 was ductile fracture.