回收多相复合材料的植物纤维填充修复方法及其对力学性能的作用机理

Waste polymer composites have a significant impact on the environment if they are not handled properly. Mechanical recycling and remanufacturing are the most economical and clean method for reusing waste thermoplastic composites. This project will focus on the waste thermoplastic multiphase composite materials for structural applications. Mechanism study of recyclable multiphase composites restored with plant fibers to improve mechanical properties will be conducted. The mechanical properties of recyclable multiphase composites will be restored by melt mixing with plant fibers. The waste composites have different degrees of ageing. The mechanical behaviors of the restored materials will be investigated in a wide range of temperatures and strain rates as they experienced in real loading conditions. Advanced characterization techniques will be applied to obtain the deformation and failure mechanisms of the materials in multi-scales. Then the deformation and failure mechanisms will be discussed with the macroscopical mechanical responses of the materials. The processing-structure-properties-performance relationship of the restored multiphase composites will be revealed. In order to predict the mechanical behaviors of the materials, a micromechanical model will be built with the consideration of loading conditions, process induced microstructures of the materials. The results of this project are expected to provide a theoretical basis and technical support for the remanufacturing and reuse of multiphase thermoplastic composites.

废旧聚合物基复合材料如不妥善处理会对环境造成较大影响。机械回收再制造是利用废旧热塑性聚合物复合材料最经济清洁的方法。本项目拟以承载用废旧热塑性聚合物基多相复合材料为研究对象，探究可回收多相复合材料的植物纤维填充修复方法及其对力学性能的作用机理，对废旧材料的绿色再制造、同等性能再利用具有重要科学意义。采用植物纤维熔融共混填充方法，修复具有不同老化程度多相复合材料的力学性能。结合多相复合材料不同承载条件，研究修复材料在宽温度和宽应变率范围下的力学行为，多尺度阐明材料的形变和失效机制，揭示再制造修复工艺-结构-性能-使用特性映射规律。建立考虑载荷条件、工艺和材料细观结构的细观力学模型，预测修复多相材料的力学行为，确保修复多相复合材料的安全应用。为植物纤维修复可回收多相热塑性复合材料的同级再利用提供理论依据和技术支持。

随着复合材料行业的蓬勃发展，其废弃物的回收再利用问题已经不容忽视。然而复合材料经过服役和回收后其力学性能会降低，不利于再次利用。为了促进复合材料废弃物的有效循环再利用，本项目选取广泛应用于载运工具的聚丙烯基复合材料为研究对象。利用环境实验机加速聚丙烯基复合材料老化过程，利用机械研磨模拟其回收过程，最后应用熔融沉积成型技术对回收老化复合材料进行再制造。并对回收前和机械回收再制造材料的物理特性、微观结构特征和力学性能进行了表征，研究了老化及机械回收对复合材料的力学性能的影响规律。结果发现老化和机械回收造成了复合材料力学性能的明显下降。为了提升回收再制造复合材料的力学性能，本项目首先对再制造工艺参数进行了优化，再采用植物纤维填充的方法对其进行修复，最后成功实现了回收再制造复合材料的力学性能提升。本项目同时探究了再制造修复复合材料在不同载荷条件下的形变和失效机理，建立了考虑再制造方法、结构、载荷条件的力学模型，为再制造修复复合材料的安全应用奠定了良好的科学基础。