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为评价热塑性结晶聚合物聚偏二氟乙烯(PVDF)对共固化复合材料动态力学和阻尼性能的影响,首先,将PVDF负载到芳纶无纺布(ANF)上,采用共固化工艺制备了PVDF-ANF/环氧树脂(EP)结构阻尼复合材料。然后,利用动态机械分析仪测试了PVDF-ANF/EP复合材料的损耗因子、损耗模量和储能模量的温度谱;通过弯曲强度、弯曲模量和层间剪切强度的测试评价了复合材料的静态力学性能;通过单悬臂梁振动实验测试了复合材料的共振频率及自由振动衰减曲线,并计算了损耗因子;通过I型、II型层间断裂韧性实验及断面微观形貌的观察研究了复合材料的断裂韧性及增韧机制。最后,对复合材料的微观结构进行分析,探讨了其兼具力学性能和阻尼性能的结构内因。结果表明:通过在ANF表面负载PVDF,可在不引起复合材料力学性能明显下降的前提下,进一步提高PVDF-ANF/EP复合材料的阻尼性能和层间断裂韧性,复合材料的损耗因子提高了33.3%,I型和II型断裂韧性分别提高了168%和208%。
To evaluate the effect of PVDF on the dynamic mechanical properties and damping properties of the co-cured composites, PVDF was first loaded onto an aramid nonwoven fabric (ANF) and a co-curing process was used to prepare PVDF -ANF / Epoxy (EP) Structural Damping Composites. Then, the temperature profile of loss factor, loss modulus and storage modulus of PVDF-ANF / EP composites were tested by dynamic mechanical analyzer. The composites were evaluated by the tests of flexural strength, flexural modulus and interlaminar shear strength The static mechanical properties of the materials were tested. The resonant frequency and free vibration decay curves of the composites were measured by single-cantilever vibration test, and the dissipation factor was calculated. Through the study of interlaminar fracture toughness of type I and II and the observation of the microstructure of the cross-section The fracture toughness and toughening mechanism of composite materials. Finally, the microstructure of the composites was analyzed, and the structural internal factors of the composites were also discussed. The results show that the damping capacity and the interlaminar fracture toughness of PVDF-ANF / EP composites can be further improved by loading PVDF on the surface of ANF. The loss factor of composites is increased by 33.3 %, Type I and Type II fracture toughness increased 168% and 208% respectively.