短切碳纤维对聚苯腈/碳纤维复合材料性能的影响

Effect of short⁃cut carbon fibers on performance of phthalonitrile/carbon fiber composites

利用碳纤维(CF)增强聚苯腈(PN)树脂制备一系列PN/CF复合材料,利用万能试验机和动态热机械分析仪(DMA),研究短CF含量、长度与偶联剂种类对PN树脂力学性能的影响。结果表明,采用苯基三乙氧基硅烷作为偶联剂时力学性能和热稳定性达到最佳水平,相较于未经偶联剂改性PN/CF复合材料的储能模量提高了22.2%,热失重5%温度(Td5%)提高了33.1%;随着CF掺杂量的增加,材料力学性能呈现先增大后减小趋势,在0.3%(质量分数,下同)时获得了最优异力学性能,相较于PN树脂,其弯曲强度提高了38.4%,弯曲模量提升了97.7%;CF长度为6 mm时材料的弯曲强度和储能模量优于CF长度为3 mm时的材料。

A series of phthalonitrile/carbon fiber composites were prepared using shortcut carbon fibers as a reinforce⁃ment agent,and the effects of the content and length of shortcut carbon fibers and the type of coupling agent on the mechanical properties of the composites were investigated using a universal testing machine and a dynamic thermome⁃chanical analyzer.The results indicated that the composites obtained optimal mechanical properties and thermal stability when phenyltriethoxysilane was used as a coupling agent.Compared to the composites without a coupling agent,the composites modified with phenyltriethoxysilane exhibited an increase in the energy storage modulus by 22.2%and in the characteristic temperature at a 5 wt%weight loss by 33.1%.With an increase in the addition amount of carbon fibers,the mechanical properties of the composites showed an increasing trend at first and then tended to decrease.The composites obtain optimal mechanical properties at a carbon⁃fiber loading of 0.3 wt%.Compared to pure phthalo⁃nitrile resin,the composites achieved an increase in bending strength by 38.4%and in bending modulus by 97.7%.The composites exhibited higher bending strength and a higher energy⁃storage modulus at a carbon⁃fiber length of 6 mm than those at a fiber length of 3 mm.