玻璃纤维表面纳米SiO_2改性对GF/PCBT复合材料力学性能的影响

为研究玻璃纤维(GF)表面纳米SiO2改性对GF增强树脂基复合材料力学性能的影响,利用真空辅助模压(VAMP)工艺制备了不同含量的纳米SiO2表面改性GF增强聚环状对苯二甲酸丁二醇酯(PCBT)复合材料。分析了GF表面改性对GF/PCBT复合材料力学性能的影响,研究了纤维表面改性对GF/PCBT复合材料抗湿热老化性能的影响规律。纤维拔出试验结果表明:经表面处理的GF/PCBT复合材料的界面剪切强度提高了1.16倍;采用含量为0.5wt%和2wt%(与树脂质量比)的纳米SiO2处理GF表面后,复合材料的三点弯曲强度分别提高1.5倍和1.67倍,弯曲模量分别提高1.03倍和1.17倍。SEM结果显示:当纳米SiO2用量为2wt%时,破坏后的纤维表面被树脂完全覆盖,树脂与纤维粘结良好。在湿热条件下,由于纳米SiO2颗粒的存在,水分子很难通过界面相扩散到改性后的材料内部,其抗湿热性能提高。

Effects of glass fiber surface modified by nano-SiO2 on mechanical properties of GF/PCBT composites

To study the effect of glass fiber (GF) surface modified by nano-SiO₂ on mechanical properties of GF reinforced matrix composites, vacuum-assisted mold pressing (VAMP) technology was adopted to prepare polymerized poly(cyclic butylene terephthalate)(PCBT)-based composites reinforced by GF modified by various nano-SiO₂ on the surface. The effect of GF surface modification on mechanical properties of the obtained GF/PCBT composites was investigated and the hygrothermal aging resistance of GF/PCBT composites with modified GF was further studied. The fiber pull-out test results show that the interface shear strength of GF/PCBT composites enhances by 1.16 times after nano modification on fiber surface. With nano-SiO₂ content of 0.5wt%, 2wt% (mass ratio of nano-SiO₂ to PCBT), the three-point flexural strength of GF/PCBT composites increases by 1.5 times and 1.67 times, flexural modulus increases by 1.03 times and 1.17 times, respectively. Observations by SEM show that the damaged fibers are covered tightly by PCBT resin when nano-SiO₂ content is 2wt%, which is an indication of good bonding properties between the matrix and fibers. Under hygrothermal conditions, hydrone diffusion along the interphase region is hindered and results in the enhancement of the anti-aging performance of the modified GF/PCBT composites, due to the existence of nano-SiO₂ particles.