导热改性碳纤维增强聚合物复合材料的力-热特性

Mechanical and thermal properties of modified carbon fiber reinforced polymer composites

借助钉扎的方法制备了一种掺杂铜柱的三相碳纤维增强聚合物复合材料,以提高其厚度方向的导热性能。在传统混合定律模型的基础上,考虑钉扎铜柱的特征长度与排布形式的影响,提出了一种改进的理论模型来预报该新型三相复合材料的导热性能,并探讨了导热改性对其力学性能的影响。结果表明,改进的理论预报模型对这种三相复合材料导热性能的预报更为准确,尤其是在钉扎铜柱体积分数较小时。在研究范围内,这种钉扎方法导热改性效果明显,力-热综合性能较好。复合材料导热性能随着钉扎铜柱体积分数的提高而增加,且增加速率不断提高,这主要源于铜柱间热影响区的产生;复合材料拉伸性能及层间剪切性能随着钉扎铜柱体积分数的增加而降低,且降低速率不断减小。当钉扎铜柱体积分数相同时,钉扎铜柱的特征长度与排布形式对复合材料导热性能与拉伸性能及层间剪切性能的影响不大。材料失效主要以钉扎孔位置挤压开裂破坏占主导,钉扎体与基体界面间的自然连接性能较弱,预计通过金属镀铜法加以改善,并可进一步提升复合材料力-热一体化特性。

Based on the pinned joints,carbon fiber reinforced polymer composites with copper bars were prepared to enhance the through-thickness thermal conductivity.Considering the effect of characteristic length and arrangement form of pinned bar,an improved theoretical model was presented to predict the thermal conductivity of the new three phase composites.The mechanical responses on the thermal conductivity enhancement were also explored.The results show that modified prediction model showed better agreement with the experiment results,especially in the range of low volume fraction for pinned bar.In the research range,the pinned joints method could realize obvious thermal conductivity enhancement,and the comprehensive performance was relatively excellent.As the volume fraction of pinned bar increased,the thermal conductivity of composites was increased,and the increasing rate was also increased due to the emergence of heat-affected zone among the pinned bars.In contrast,the tensile and interlaminar shear property gradually decreased,and the loss rate was also slowed down.When the volume fraction of pinned bar was the same,the effects of the characteristic length and arrangement form of bar on the thermal and mechanical properties were unobvious.The squeezing crack of pinned holes became the dominated failure mode,and interface connection between pinned bars and composite matrix was weak,which could be expected to improve by the copper plating technology and simultaneously realized the further enhancement of mechanical-thermal performances.