磁性石墨烯/聚氨酯柔性复合材料的制备及自修复效能

Preparation and self-repairing efficiency of magnetic graphene/polyurethane flexible composites

为了提高复合材料的导电、导热及自修复性能,在传统共混法的基础上采用化学沉积法将四氧化三铁(Fe3O4)修饰到石墨烯上,得到磁性石墨烯,并将其与聚氨酯、碳纳米管共混后经磁场干预控制石墨烯片层的排列得到磁性石墨烯/聚氨酯柔性复合材料。采用SEM、Raman、FTIR对柔性复合材料的微观形貌、分子结构进行表征,并通过激光导热仪、四探针电阻率测定仪和万能试验机分析磁场调控对复合材料电、热、力学以及修复性能的影响。结果表明:磁场下柔性复合材料中的石墨烯片层排列规则,且层次分明,轮廓清晰可见;其热扩散系数相比于未加磁场提高了10%~12%,且在高温下具有稳定性,缺陷修复时间减少了50%;对比出现缺陷前及修复后的复合材料发现,表面电阻率和抗拉强度分别相差0.006Ω·cm和2.4MPa,而无磁场环境下的变化量是其3~4倍。

In order to improve the conductivity,heat conduction and self-repairing properties of composites,ferroferric oxide(Fe3O4)was modified on graphene by chemical deposition on the basis of traditional blending method to obtain magnetic graphene.The magnetic graphene/polyurethane flexible composites were prepared by blending with polyurethane,carbon nanotubes and magnetic grapheme,and controlling the arrangement of graphene sheets by magnetic field interference.Microstructure and molecular structure of flexible composites were characterized by SEM,Raman and FTIR.And the effects of magnetic field regulation on the electrical,thermal,mechanical and repair properties of composites were analyzed by laser thermal conductivity meter,four-probe resistivity meter and universal testing machine.The results showed that the graphene sheets in flexible composites were arranged regularly under magnetic field with distinct layers and clear contours.Compare with that without magnetic field,its thermal diffusivity increased by 10%~12%,and was stable at high temperature.The repair time of defect decreased by 50%.Contrast defect found before and after repair of composite materials,the surface resistivity and tensile strength were differ by 0.006Ω·cm and 2.4MPa,respectively,and the variation was 3~4 times in the absence of magnetic field.