碳纤维网络增强环氧树脂基复合材料的制备与表征

为提高碳纤维/环氧树脂复合材料的刚性和热尺寸稳定性,首先利用短切碳纤维制备了碳纤维网络增强体(CFNR),并将其与环氧树脂复合制备了CFNR/环氧树脂新型复合材料。然后,分别利用扫描电镜和热机械分析仪对CFNR/环氧树脂复合材料的微观结构和热力学性能进行了表征。结果表明:CFNR/环氧树脂复合材料中有明显的网络节点,即碳质粘结点;CFNR/环氧树脂复合材料具有较好的导电性、较高的刚性和较低的热膨胀性,其弹性模量分别为常规短切碳纤维/环氧树脂复合材料及纯环氧树脂的3倍和6倍,平均热膨胀系数(60~200℃)分别为常规短切碳纤维/环氧树脂复合材料的1/15及纯环氧树脂的1/40;随着温度升高,CFNR/环氧树脂复合材料、常规短切碳纤维/环氧树脂复合材料及纯环氧树脂的弹性模量均因环氧树脂变软而降低,当温度高于80℃时,CFNR/环氧树脂复合材料的弹性模量分别约为常规短切碳纤维/环氧树脂复合材料的7倍和纯环氧树脂的近70倍。研究结论可以为开发高刚性、低膨胀聚合物基复合材料提供实验依据和理论指导。

Fabrication and characterization of carbon fiber network reinforced epoxy matrix composites

In order to promote the stiffness and thermal dimensional stability of carbon fiber/epoxy composites, carbon fiber network reinforcement (CFNR) was fabricated firstly by short carbon fiber, and mixed with epoxy to prepare new type of CFRN/epoxy composites. Then, the microstructure and thermal mechanical properties of CFRN/epoxy composite were characterized by scanning electron microscopy and thermal mechanical analyzer, respectively. The results indicate that there are obvious network nodes of carbon-based adhesive points in CFNR/epoxy composites, and CFNR/epoxy composites exhibit relatively high electric conductivity, high stiffness and low thermal expansion, the elastic modulus is about 3 times and 6 times of that of regular short carbon fiber/epoxy composite and pure epoxy, respectively. The average thermal expansion coefficient (60-200 ℃) is 1/15 of that of regular short carbon fiber/epoxy composite, and 1/40 of that of pure epoxy, respectively. With the temperature increasing, the elastic moduli of CFNR/epoxy composite, regular short carbon fiber/epoxy composite and pure epoxy are dropping due to the softening of epoxy. When the temperature is above 80 ℃, the elastic modulus of CFNR/epoxy composite is about 7 times of that of regular short carbon fiber/epoxy composite, and nearly 70 times of that of pure epoxy. The research conclusions can provide experimental basis and theoretical direction for the exploring of polymer matrix composites with high stiffness and low thermal expansion.