γ-射线辐照PBO纤维强化与表面活化协同作用机制研究

Abstract.PBO fibers are important reinforcement materials for resin matrix composites, but The fiber strength displaying in composites is severe influenced by its microfibril structure and smooth inert surface.Improvement study is now an key and hot problem for the use of PBO fibers. It has been indicated that the flexure strength and compression strength of PBO fiber composites were obviously improved when the surface of PBO fiber was activated by gamma ray irradiation, but the mechanics is not clear. Hence, we will investigated at molecule structure level the structure changes、cross linking reactions of PBO model compounds and grafting reactions between PBO model compounds and grafting media by gamma ray irradition, and further sdudy the changes of the crystal structure、microfibril structure and surface microstructure of irradiated PBO fiber to explore the evolvement regularity of fiber micro-structure and the effects of fiber surface activation.The mechanics of cross linking reactions between PBO molecules and fiber surface activition will be confirmed combining with the structure changes of PBO model compounds.The effect of irradiatted fiber micro-structure and surface activity on the mechanical properties of PBO fiber/epoxy composites will be investigated, and the ralationships of gamma ray irradiation dose, the degree of structure evolvement and the number of surface active groups be adjusted to realize the co-action for the improvement of mechanical properties and activation of fiber surface.Then the co-mechanics will be disclosured. A new technical method for the improvement of PBO fiber properties is presented. This project is meaningful to extend the use of PBO fibers.

PBO纤维是树脂基复合材料重要的增强材料，但纤维特有的微纤结构和光滑且惰性的表面，严重影响其在复合材料中的强度发挥，改性研究是目前PBO纤维应用的关键和热点问题。研究发现γ射线辐照活化PBO纤维表面的同时纤维复合材料弯曲性能和轴向压缩性能也有明显的改善，但作用机理不详。课题从分子结构角度出发，研究γ射线辐照PBO模型化合物的结构变化、分子间反应及其与辐照介质之间的接枝反应，进一步分析辐照PBO纤维的结晶结构、微纤结构和表面微结构的变化，研究纤维微观结构的演化规律和纤维表面活化效果，结合辐照模型化合物的结构变化，探讨PBO纤维微纤间的交联反应机制，确定辐照纤维表面的活化作用机制。调控辐照能量与纤维微结构演化和表面活化的关系，深入研究辐照纤维微结构和表面活性对复合材料力学性能影响，揭示PBO纤维强化与表面活化的协同作用机制。为PBO纤维改性提供新的技术方法，这对PBO纤维推广应用具有重要意义。

项目针对PBO 纤维特有的表面光滑且惰性和微纤化的问题，开展了表面活化与本体强化的改性研究。从分子结构角度出发，研究了γ射线辐照PBO 模型化合物的结构变化、分子间反应及其与辐照介质之间的接枝反应，进一步分析了辐照PBO 纤维的结晶结构、微纤结构和表面微结构的变化，研究结果显示，γ射线辐照能够将极性分子接枝到PBO纤维表面，增加纤维表面活性，提高了纤维表面能和表面粗糙度，但是并没有改变纤维本体结晶结构和拉伸强度；结合辐照模型化合物的结构变化，确定了PBO 纤维微纤间的交联反应，表明γ射线辐照改善了纤维微纤开裂现象和抗压性能；建立了辐照剂量对微观结构演化的影响规律和纤维表面活化与本体强化作用机制。进一步研究了辐照纤维微结构和表面活性对复合材料界面性能和力学性能影响，结果表明辐照改性显著提高了PBO纤维复合材料的界面粘接强度和弯曲强度。研究成果为PBO 纤维改性提供新的技术方法，这对PBO 纤维推广应用具有重要意义。