基于高温蒸汽热解的碳纤维复合材料高效回收及其性能

Highly Efficient Recycling of Carbon Fiber Reinforced Composites by Pyrolysis with Superheated Steam and Their Properties

采用高温蒸汽热解方法实现了碳纤维增强环氧复合材料中碳纤维的高效热解回收及再生利用。研究了热解温度、时间及气氛等因素对碳纤维回收效率及性能的影响,通过扫描电镜(SEM),热重分析(TGA),X射线光电子能谱(XPS),单丝力学拉伸及高温接触角测试重点考察了回收碳纤维的表面形貌、力学性能及界面浸润性等性能变化情况。研究结果表明,复合材料在520~550℃无氧蒸汽条件下2~3h时能够实现最优化的树脂降解及纤维性能保持率,能够得到表面较为干净的碳纤维,表面树脂残存率<2%,拉伸力学性能保持率≥90%,回收效果良好。通过真空辅助树脂灌注(VARI)工艺制备得到的再生碳纤维复合材料保持着良好的力学性能,弯曲强度保持率>85%,层间剪切强度基本没有下降,验证了回收碳纤维的再利用可行性。

Recycled carbon fibers(RCFs)were prepared from carbon fiber reinforced plastics(CFRPs)by pyrolysis with superheated steam.The influence of pyrolysis temperature,time and atmosphere factors on the degradation effect of epoxy resin matrix and the properties of the RCFs were investigated.The surface morphology,mechanical properties and wettability were studied by scanning electron microscopy(SEM),thermogravimetric analysis(TGA),X-ray photoelectron spectroscopy(XPS),monofilament tensile and contact angle test.The results show the CFRPs can be efficiently depolymerized and almost clean RCFs can be obtained under the optimal decomposition conditions at 520-550℃for 2-3 h.The tensile tests show that the effect of temperature on the tensile strength of recycled CFs was more obvious than time.The tensile strength and modulus retention of RCFs can reach above 90%and 94%compared to those of the virgin fibers,respectively,which indicates that most of the mechanical strength can be retained by superheated steam method.The RCFs were re-used to remanufacture new composites by vacuum assistant resin infusion(VARI)technology,which showing acceptable mechanical properties in comparison to virgin composites.The retention rate of flexural strength can reach above 85%and the interlaminar shear strength shows no reduction for the reclaimed composites,indicating the reusing possibility of RCFs from CFRPs.