EP/SiO_2/CF复合材料的动态热力学分析

为了研究纳米级SiO_2、碳纤维(CF)对环氧树脂(EP)基复合材料动态热力学性能的影响,制备了不同用量(分别为EP质量的0%和4%)纳米SiO_2、不同体积分数(分别为5%,10%,15%,20%)CF增强EP基复合材料弯曲试样,对试样进行了多频扫描动态热力学分析(DMA),研究了纳米SiO_2和CF对复合材料玻璃化转变温度(Tg)、储能模量、表观活化能和最大损耗因子的影响。结果表明,总体上添加4%的纳米SiO_2后复合材料的Tg下降2~6℃;100℃之前,测试频率对复合材料的储能模量影响较小,且未含SiO_2的试样储能模量曲线比含SiO_2的试样较为平坦;当CF体积分数分别为10%,15%,20%时,添加4%纳米SiO_2的EP/CF复合材料的在40℃下的储能模量较未加纳米SiO_2时提升31.2%,135.5%,13.6%,表明纳米SiO_2和CF展现出很好的协同效应从而提升了复合材料储能模量,而最大损耗因子分别下降3.7%,6.5%,14.8%,表明纳米级SiO_2有助于增强复合材料的刚性;当纳米SiO_2用量为EP质量的4%,CF体积分数为15%时,复合材料内部作用力最大,表观活化能达到569 k J/mol,呈现了很好的协同效果。

Dynamic Thermomechanical Analysis of Epoxy Resin/Silica/Carbon Fiber Composites

In order to investigate the effects of nano-silica (SiO2) and carbonfiber (CF) on the dynamic thermomechanical per-formances of epoxy resin (EP) based composites,the composite bending specimens with different contents of nano-SiO2 (respectively 0% and 4% of EP mass) and different volume percentage of carbonfibers (respectively 5%,10%,15% and 20%) were prepared. The DMA with multi-frequency scanning were conducted for the specimens,the effects of nano-SiO2 and CF on the glass transition temperature (Tg),storage modulus,apparent activation energy and maximum loss factor of the composites were studied. The results show that,Tg of the composites added with nano-SiO2 decrease by 2–6℃ as a whole. Before 100℃,the test frequency has less im-pact on the storage modulus of the composites,and the storage modulus curves of the composites without nano-SiO2 sample are rela-tively moreflat than those containing nano-SiO2. When the volume fraction of CF is 10%,15 % and 20%, adding 4% nano-SiO2,the storage modulus of the composite at 40℃ increases by 31.2%,135.5%,13.6% respectively compared with the composites without nano-SiO2,which indicates that nano-SiO2 and CF exhibit good synergistic effect for promoting the storage modulus,moreover, the maximum loss factor decreases by 3.7%,6.5%,14.8% respectively,which shows that nano-SiO2 can help to enhance the rigidity of the composites. When the content of nano-SiO2 is 4% of EP mass and the volume fraction of CF is 15%,the internal force of the composite reaches maximum and the apparent activation energy is 569 kJ/mol,which shows a good synergistic effect.