三维编织炭纤维增强环氧树脂复合材料的吸湿特性

为了研究三维编织复合材料的吸湿行为，利用树脂传递模塑（RTM）工艺制备了三维编织炭纤维增强环氧树脂（C3D／EP）复合材料．通过吸水实验，研究了该材料的吸湿规律、温度对吸湿的影响以及吸湿过程中复合材料力争陛能的变化．结果表明：C3D／EP复合材料吸湿初期符合Fick扩散定律，但整个吸湿行为可用Sigmoidal曲线来描述；温度可加速C3D/EP复合材料的吸湿速率，并使平衡吸湿量提高；在吸湿过程中，C3D／EP复合材料的弯曲强度随吸湿时间的延长而下降，先快后慢，与吸湿曲线相对应，而且温度越高，下降越明显，表明吸湿量的大小决定了力学性能的降低程度．

Moisture Absorption Characteristics of 3D Braided Carbon Fiber Reinforced Epoxy Resin Composites

Three-dimensionally （3D） braided carbon fiber reinforced epoxy resin （C3D/EP） composites have been prepared by resin transfer molding （RTM）process. The moisture absorption characteristics ,influence of temperature on the water uptake, and changes in the fiexural strength during water absorption of C3D/EP composites have been studied in the water absorption experiment. Experiment results show that the equilibrium moisture content of the C3D/EP composites is lower than that of unreinforced epoxy resin but slightly higher than that of the long carbon fiber reinforced epoxy resin （CL/EP） composites. The absorption behavior at the initial stage conforms to Fick＇s law of diffusion while the whole absorption behavior of epoxy resin composites can be described with the Sigmoidal model. The flexural strength of the C3D/EP composites decreases quickly with immersion time at the early stage and then levels off,which is in agreement with the absorption content-time curve. It is also found that temperature affects the absorption process greatly. The absorption rate and equilibrium moisture content of the C3D/EP composites increase with the rise of temperature. The higher the temperature, more remarkable the loss of flexural strength. It is thus concluded that the reduction of mechanical property is related to the water absorption content of the C3D/EP composites.