炭纤维表面聚酰亚胺涂层的制备及表征

摘要

Organic, solvent-free polyamic acid sizing was coated onto T300 grade carbon fibers (3k) to prepare a polyimide (PI) coating having a high thermal stability and oxidative resistance. The surface of PI-coated carbon fibers was characterized by FTIR and SEM. The mechanical strength of the carbon fibers, thermal stability and oxidative resistance of the coating were also investiga-ted. Results indicate that a continuous and uniform PI coating is formed on the surface of the carbon fibers. Compared to a carbon fiber coating with epoxy, the PI coating produces excellent thermal stability with onset decomposition and a 5% weight-loss tempera-tures of 567 and 619 ℃, respectively. The tensile strength of PI-coated carbon fibers after thermal oxidation in air at 400 ℃ for 1 h has only a slight decrease of 6%, which is significantly lower than the decrease of 22% for epoxy-coated fibers.%采用一种不含有机溶剂的聚酰胺酸上浆剂实施上浆处理,为在T300级炭纤维(3 k)表面制备聚酰亚胺( PI)涂层提供一种绿色途径。通过傅里叶变换红外光谱和扫描电子显微镜对PI涂覆炭纤维的表面进行分析,结果表明,在炭纤维表面形成一层连续且均一的PI涂层。通过热重分析和单丝拉伸测试,考察炭纤维的热稳定性。与包含环氧上浆剂的炭纤维相比,在耐高温树脂的加工温度范围(300~400℃)内PI涂覆炭纤维表现出优异的热稳定性,起始分解温度与5%热失重温度分别高达567℃及619℃。此外,在空气中、400℃条件下氧化1 h后,PI涂覆炭纤维的拉伸强度仅下降6%,明显低于包含环氧上浆剂炭纤维(拉伸强度下降22%)。