醋酸溶胀回收废弃碳纤维增强聚合物基复合材料

Recycling of waste carbon fiber-reinforced polymer composite by acetic acid swelling method

针对废弃碳纤维增强聚合物基复合材料(CFRP)在机械法回收过程中碳纤维长度和强度损失较高的难题,采用醋酸溶胀法改善CFRP机械加工性能,以降低碳纤维长度和强度损失,提高CFRP机械回收产物再利用价值。结果表明,CFRP中的固化环氧树脂(CEP)能够在醋酸介质中快速溶胀并发生轻微降解。CFRP在140°C醋酸中浸泡1 h会发生软化现象(树脂溶胀率和降解率分别为78.88%和4.49%),当温度提升至160~220°C后CFRP会发生分层现象(树脂溶胀率为101.54%~147.00%,降解率为9.08%~14.40%)。这些软化或分层产物易于被机械裁切成细条状、薄片状或其他各种形状。将烘干后的裁切产物或分层产物与适量未固化环氧树脂混合,采用热压法可重新制备CFRP。新制备的CFRP的抗弯强度可达到原始CFRP的47%~89%。本研究结果可为热固性环氧树脂复合材料绿色回收提供参考。

The losses of carbon fiber length and strength were high during the mechanical recycling process of the waste carbon fiber-reinforced polymer composite(CFRP).In response to this problem,acetic acid swelling method was used to improve the machinability of CFRP in order to reduce the losses of carbon fiber length and strength and improve the reuse value of CFRP mechanical recycled products.The results showed that cured epoxy resin(CEP) in CFRP could be fully swelled and slightly degraded in acetic acid medium.The stiff CFRP became soft in the acetic acid medium at 140 ℃(swelling ratio and degradation ratio were 78.88% and 4.49%,respectively),and it delaminated into soft single CFRP layers at 160 ℃–220 ℃ within 1 h(swelling ratio and degradation ratio were 101.54%~147.00% and 9.08%~14.40%,respectively).Thus,the swollen CFRP can be easily cut into long strips,large thin slices,or other customized shapes while the length and strength of the carbon fibers were preserved well.The shear and delamination products(after drying) were mixed with uncured epoxy resin and prepared into new CFRP products through hot pressing method.The flexural strength of reprepared CFRP boards can reach 47%~89% of the original CFRP board.This work can provide a green method for thermosetting composites recycling.