聚氨酯/纳米SiO_(2)改性碳纤维增强环氧树脂复合材料界面性能

Interfacial properties of polyurethane/nano-SiO_(2) modified carbon fiber epoxy resin composites

聚合物与纤维之间的界面性能对提升复合材料力学性能尤为重要。本文采用异氰酸根(-NCO)封端的聚氨酯(PU)分子对纳米SiO_(2)表面进行改性,同时采用KH550对碳纤维(CF)进行表面改性,利用-NH2与-NCO较高的反应活性,在CF和纳米SiO_(2)粒子间通过PU分子链形成共价键连接。结果显示:PU极性分子链的引入,提高了CF的表面能,使其表面润湿性显著提高。相较于KH550直接接枝纳米粒子的碳纤维(CF-KH550-SiO_(2)),通过PU分子链接枝纳米粒子的碳纤维(CF-KH550-PU-SiO_(2)),其表面能提升23.0%,表面纳米SiO_(2)粒子的接枝率和分散均匀性也明显提升。CF-KH550-PU-SiO_(2)/环氧树脂(EP)的界面剪切强度(IFSS)和层间剪切强度(ILSS)相比未改性CF/EP分别提高72.9%和47.9%,相比CF-KH550-SiO_(2)/EP分别提高17.3%和11.2%。

The interfacial properties between polymer and fiber are particularly important for improving the mechanical properties of composites.In this paper,the surface of nano-SiO_(2) was modified by polyurethane(PU)capped by isocyanate(−NCO),and the surface of carbon fiber(CF)was modified by KH550.Because of the high reactivity of−NH2 and−NCO,the covalent bond was formed between CF and nano-SiO_(2) particles through PU molecular chain.The results showed that the introduction of PU polar molecular chain improved the surface energy and wettability of CF.Compared with the CF directly grafted with nano particles by KH550(CF-KH550-SiO_(2)),the surface energy of the CF with nano particles linked by PU(CF-KH550-PU-SiO_(2))molecules increased by 23.0%,and the grafting rate and dispersion uniformity of surface nano SiO_(2) particles also improved significantly.Compared with the untreaed CF/epoxy resin(EP)composites,the interfacial strength(IFSS)and the interlaminar shear strength(ILSS)of CF-KH550-PU-SiO_(2)/EP composites increased by 72.9%and 47.9%respectively.Compared with the CF-KH550-SiO_(2)/EP composites,IFSS and ILSS of CF-KH550-PU-SiO_(2)/EP composites increased by 17.3%and 11.2%,respectively.