氧化石墨烯/聚乙烯醇复合材料的纳米压痕实验及力学性能

Nanoindentation and mechanical properties of graphene oxide/poly(vinyl alcohol)composites

为了研究氧化石墨烯(GO)对聚合物基复合材料力学性能的影响,通过溶液混合法制备了GO/聚乙烯醇(PVA)复合材料。然后,采用XRD、TEM、FTIR、DSC和纳米压痕实验等研究了GO/PVA复合材料的结构、界面结合性能、力学性能、蠕变行为和吸水膨胀率。结果表明:GO可以均匀分散在PVA基体中,二者之间主要通过氢键作用结合,具有较高的界面结合力;与纯PVA相比,1wt%GO/PVA复合材料的硬度和有效弹性模量分别提高了28.9%和23.3%,压入蠕变深度下降了19.8%;GO/PVA复合材料具有较低的无限剪切模量与瞬时剪切模量比,表明GO提高了PVA的蠕变抗力;GO的添加同时增加了GO/PVA复合材料的阻水性并降低了膨胀系数。吸湿纳米压痕实验结果表明:纯PVA的力学性能会随吸湿时间延长而下降,而GO/PVA复合材料吸湿72h后的力学性能基本保持不变。所得结论为石墨烯增强聚合物基复合材料的研究提供了理论指导。

In order to investigate the effects of graphene oxide （GO） on the mechanical properties of polymer matrix composites, GO/poly（vinyl alcohol） （PVA） composites were prepared by solution mixing method firstly. Then, the structure, interracial bonding properties, mechanical properties, creep behaviors and water swelling rate of GO/ PVA composites were investigate by XRD, TEM, FTIR, DSC, nanoindentation and so on. The results show that GO can be dispersed well in the PVA matrix, both of them are mainly combined through hydrogen bond interaction which has higher interface bonding force. Comparing with that of pure PVA, the hardness and effective elastic mod ulus of 1 wt% GO/PVA composite enhance by 28.9 % and 23.3%, respectively, and the indentation creep depth de clines by 19.8%. GO/PVA composites show the lower ratios of infinite shear modulus to instantaneous shear modu lus, which indicates that GO improves the creep resistance of PVA. The addition of GO also improves the water proofness of GO/PVA composites and decreases swelling factor. The experimental results of moisture absorption nanoindentation show that the mechanical properties of pure PVA decline with the moisture absorption time increas ing, while the mechanical properties of GO/PVA composite almost remain the same after moisture absorption for 72 h. The obtained conclusions provide theoretic guidance for the research of graphene reinforced polymer matrix composites.