摘要
环氧树脂基碳纤维增强复合材料因其优异的力学、热学性能已广泛应用于航天航空等领域。环氧树脂由三维共价交联网络组成,难以被降解。工业中通常需高温(300~800℃)、高压(3~27 MPa)等严苛环境或有毒催化剂来破坏树脂基体,以回收复合材料废弃物中昂贵的碳纤维,这一过程往往会造成纤维性能的严重损失。本文利用环氧树脂与醇溶剂之间的动态键交换反应,将工业中常用的高性能环氧树脂降解为低聚物,降解条件温和(200℃、0 MPa),且无需额外催化剂。通过树脂降解,回收得到结构完整的碳纤维织物,其强度保持在94%以上,可继续用于制备复合材料。将低聚物作为反应物制备新的环氧树脂,称为再制造环氧树脂。当再制造环氧树脂中低聚物的含量为20wt%时,其强度与原环氧树脂相当,而断裂伸长率提高了20%。用再制造环氧树脂制备碳纤维复合材料,其强度与原环氧基复合材料相当,同时断裂伸长率提高了50%。本文实现了工业用环氧树脂及其复合材料从制造到回收到再制造过程,即闭环回收再制造。同时,本文新提出了一种绿色、简单、有效的环氧树脂增韧方法。
High-performance carbon fiber reinforced epoxy composites have become important materials for aircraft manufacturing due to their excellent mechanical and thermal properties.The three-dimensional crosslinked network of epoxy matrix is insoluble,making degrading and recycling challenging.In engineering,to reclaim the expensive carbon fiber from composite wastes,harsh conditions such as high temperature(300-800℃),high pressure(3-27 MPa),and trenchant catalyst are usually demanded to destroy the epoxy matrix.However,the properties of carbon fibers are deteriorated simultaneously.In this work,high-performance epoxy resin was decomposed into oligomers via the bond exchange reactions between the epoxy and alcohol solvent.The epoxy resin was dissolved in the alcohol solvent at mild condition(200℃,0 MPa).Meanwhile,the woven structure of the recycled fabric remains intact,and its tensile strength is 94%of the fresh fabric.Thereby,the recycled fabrics can be used to prepare new composites.Furthermore,the decomposed epoxy oligomer(DEO)is used as a reactant to prepare new epoxy resin.When the DEO content is 20wt%,the elongation at break of the new resin is significantly improved by 20%,while its strength is similar to the original epoxy resin.For the same DEO content,the elongation at break of remanufactured epoxy composites increased by 50%,compared to the fresh one.To sum up,we develop a closed-loop recycling and re-manufacturing method for an epoxy resin and its composite,and a novel method for the toughen ing of epoxy resin that is eco-friendly,easy and efficient.
作者
安乐
赵文哲
金宸宇
AN Le;ZHAO Wenzhe;JIN Chenyu(School of Aerospace Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2023年第5期2575-2586,共12页
Acta Materiae Compositae Sinica
基金
国家重点研发计划(2019YFA0706800)
中国博士后基金面上项目(2019M663676)
中央高校基础科研业务费(xjh012019035)。
关键词
环氧树脂
复合材料
键交换
回收再制造
增韧
epoxy
composite
bond exchange reaction
recycling and re-manufacturing
toughening
