微波辅助MgO改性碳纤维增强增韧环氧树脂复合材料

Investigation of microwave-assisted MgO-modified carbon fiber-reinforced and toughened epoxy resin composites

对碳纤维表面进行改性处理是提高碳纤维/环氧树脂复合材料(CFs/EP)界面结合力的主要方法,而特殊的表面形貌结构能有效预防应力集中并提升复合材料的综合力学性能。本文采用微波辅助的方法在碳纤维表面快速高效地制备了一种花朵状MgO,考察了其对CFs/EP复合材料力学性能的影响。研究发现:花朵状MgO增加了碳纤维表面的粗糙程度,促进了碳纤维与EP基体不规则界面的形成,增强了其与EP基体的机械啮合作用。这种多尺度边界形态可以增加裂纹扩展途径,从而消耗更多的能量并有效缓解CFs/EP复合材料因应力集中而产生的破坏。花朵状MgO改性碳纤维极大地改善了复合材料的力学性能,与未改性碳纤维增强环氧树脂相比,花朵状MgO改性碳纤维/环氧树脂复合材料的拉伸强度、弯曲强度和冲击强度分别提高了15.2%、21.8%和14.3%。因此,花朵状MgO改性碳纤维同时显著提高了CFs/EP复合材料的强度和韧性。这为碳纤维在聚合物基复合材料中的广泛应用提供了技术支持,为制备更多特殊形貌纤维增强树脂基复合材料提供了更广阔的思路。

Surface modification of carbon fiber is the primary method for enhancing the interface bonding strength of carbon fiber/epoxy resin composite(CFs/EP).The unique surface morphology can effectively prevent stress concentration and enhance the comprehensive mechanical properties of the composite.A flower-shaped MgO was synthesized on the surface of carbon fibers rapidly and efficiently using a microwave-assisted method,and its impact on the mechanical properties of CFs/EP composites was investigated.It was found that the flower-like MgO increased the roughness of carbon fiber surface markedly.So irregular interface between carbon fiber and EP matrix formed.As a result,the mechanical interlocking force between carbon fiber and EP matrix was enhanced significantly.This multiscale boundary morphology could increase the crack propagation path.Thereby,more energy could be consumed and the failure of CFs/EP composites caused by stress concentration could be alleviated effectively.Compared to unmodified CFs/EP composite,MgO-modified CFs/EP composite exhibited a 15.2%,21.8%,and 14.3%increase in tensile strength,bending strength and impact strength,respectively.Therefore,Mg0-modified carbon fiber improved the strength and toughness of carbon fibers significantly.The research provides technique support for the wider application of carbon fibers in polymer composite.Meanwhile,it extends broader ideas for fibers with much more unique surface morphologies in strengthening polymer composite.