微波强化低能电子束固化复合材料界面作用机制与工艺研究

With the increasing of the size of composites structure parts for industrial use, the autoclave process for composites is becoming more and more difficulty to control, and the cost is increasing rapidly, which blocked the further use of composites in industry area. The manufacture process of Electron Beam (EB) curing composites is much simple than autoclave process, and the combination property of composites cured by EB is better than that cured by autoclave. The EB curing technology is one of the promising out-clave process for low cost composites manufacture.But the lower interlayer shear strength (ILSS) is the main cause to block the wide use of composites cured by EB in industry products.In this project,a novel resolvent of interface enhancing is proposed to overcome the low ILSS of the composites cured by EB.Because the resin molecules would vibrate and rub with very high frequency because of the microwave, which results in high temperature around the fibres and intense interfunction between the resin molecules and the surface of fibre, finally the interface function between resin and fibres is enhanced by microwave.In this project,the enhancing mechnism of resin/fibre interface by microwave would be investigated; The coupling mechnism and rule of microwave and loe energy EB would be researched, and evaluation method of enhancing effects would be founded; The relation ship between coupling paremeters and properties of the composites cured by microwave and low energy EB would be clarified;A novel low cost maufacture method and process base of polymer composites would also be founded in this project.The research work will improve the manufacturing level of polymer composites in China, and provide adcanced maufaturing method and theory having self-owned intellectual property for manufacture of large size polymer composites parts.

随着复合材料构件的大型化，热压罐固化工艺控制难度大、成本高的问题越来越突出。电子束固化复合材料工艺简单，制备的复合材料构件综合性能优于传统热固化复合材料，是替代热压罐工艺的下一代低成本复合材料制造技术。但较小的层间剪切强度是制约电子束固化复合材料工业化应用的技术瓶颈。项目组提出采用微波激发分子高频振动摩擦生热原理强化电子束固化中树脂分子与纤维界面相互作用的新技术思路，解决电子束固结复合材料构件层间剪切强度较差的技术难题。通过项目研究阐明微波强化树脂/纤维界面作用的机制与物理本质，揭示微波与低能电子束协同耦合固化复合材料的作用机制与规律，并获取相应的强化效果评价方法，明确微波与低能电子束耦合作用工艺参数对构件性能影响关系，建立高强度大型复合材料构件低成本制造新方法与工艺基础。项目研究工作有助于提升我国树脂基复合材料成型制造水平，为大型复合材料构件提供具有自主知识产权的先进成型制造方法与理论。

针对低能电子束固化的碳纤维增强树脂基复合材料界面性能差的问题，项目组采用2450MHz频率的微波对碳纤维/树脂预浸带进行短时辐照，利用微波作用下碳纤维电阻损耗及树脂介电损耗机制产生的内热，改变碳纤维表面形貌与组份，强化纤维与树脂界面粘接质量，进而改善复合材料的层间力学性能。. 首先，研究了微波强化碳纤维/树脂界面的作用机制。通过建立微波对碳纤维/树脂作用过程物理模型，模拟了微波场对纤维、树脂及界面的作用过程。结合微波理论及建立的微波作用物理模型，明确了微波对碳纤维和树脂两个相的作用机理：碳纤维的电阻损耗与树脂基体的介电损耗导致温度上升，进而改变碳纤维表面形貌及组份；其次，研究了微波辐照下树脂/纤维界面的演化规律，分别对碳纤维表面微观形貌、O/C原子比、官能团几个角度进行了实验与对比分析，结果显示经微波处理后碳纤维表面粗糙度增加，O/C原子比增加，活性官能团数量增加，这些因素导致树脂与纤维粘接质量明显改善，碳纤维/树脂界面剪切强度提高30%左右；再次，研究了微波辐照时间，微波辐照方式对低能电子固化复合材料性能的影响规律，明确了微波强化碳纤维/树脂界面与低能电子束固化复合材料力学性能关联关系。实验结果表明微波预处理后复合材料的层间剪切强度最大提高24.7%，同时复合材料的拉伸强度及断裂韧性也有一定程度的提高；针对微波辐照不均匀导致复合材料性能一致性差的问题，通过控制极化角及采用单一波源多波导阵列改善辐照空间内的电场分布，初步实现了微波辐照均匀性的控制；最后，对微波与低能电子束集成作用工艺参数进行了优化，研究结果显示微波的引入能够降低复合材料的固化反应活化能，间歇式微波辐照及双面不等剂量电子束固化辐照固化工艺可以最大程度加工层间力学性能及缩短固化时间。. 项目研究成果对低成本高质量低能电子束固化复合材料制造具有重要的理论参考价值，将进一步加快低能电子束原位固化工艺的工程化应用。