尼龙66/氧化石墨烯纳米复合材料力学性能的分子动力学模拟

Molecular Dynamic Dimulation on the Mechanical Properties of Nylon66/Graphene Oxide Nanocomposites

氧化石墨烯是一种理想的纳米填料,可以用于提高聚合物复合材料的力学性能。利用分子动力学模拟和ReaxFF反应力场研究了尼龙66/氧化石墨烯纳米复合材料的力学性能。模拟结果表明:氧化石墨烯片在尼龙66基体中具有较好的分散性,加入5片氧化石墨烯片后(质量分数为3%),尼龙复合材料在室温下的密度为1.12g/cm3,玻璃化转变温度为389 K;复合材料的屈服强度和杨氏模量比纯尼龙66分别提高了27%和49%,达到2 512 MPa和9 448 MPa;氧化石墨烯分子和尼龙分子链间能形成分子间氢键,通过氢键分析揭示了尼龙66/氧化石墨烯复合材料力学性能增强的微观机理,当拉伸过程开始后,每片氧化石墨烯和尼龙分子链间的氢键数量保持在3~4个,这些分子间氢键使得氧化石墨烯片和尼龙分子间保持着较强的结合力,尼龙基体所受的拉伸应力能够转移到强度更高的氧化石墨烯片上,从而实现材料力学性能增强的效果。

Graphene oxide is an ideal nanometer filler,which can improve the mechanical properties of polymer composites.The mechanical properties of nylon 66/graphene oxide nanocomposites were studied by molecular dynamics simulation and ReaxFF force field.The simulation results show that the graphene oxide nanoplates have good dispersibility in the nylon 66 matrix.After adding 5 pieces of graphene oxide nanoplates,the mass fraction is 3%,the density of nylon composites at room temperature is 1.12 g/cm3 and the glass transition temperature is 389 K.The yield strength and young＇s modulus of composite materials increase by 27%and 49%respectively compared to that of pure nylon 66,reaching 2 512 MPa and 9 448 MPa.The microscopic reinforcement mechanism of the nylon 66/graphene oxide composites was investigated by hydrogen bond analysis.The results show that intermolecular hydrogen bonds can form between the molecules of graphene oxide and nylon 66.After the stretching process begins,the number of hydrogen bonds formed between each graphene oxide nanoplates and each nylon molecules chain is kept from 3 to 4.These intermolecular hydrogen bonds lead to a strong bonding force between graphene oxide nanoplates and nylon molecules chain.As a result,tensile stress of nylon matrix can be transferred to graphene oxide nanoplates with higher strength,which brings about an effect of material reinforcement.