以氧化石墨烯为原料,采用3-氨丙基三乙氧基硅烷对其进行氨基化改性,利用水解产生的硅羟基和氧化石墨烯表面的含氧官能团进行缩合反应后,在使用二乙醇胺进行还原,得到改性还原石墨烯,对改性结果进行红外光谱分析。将其作为导热填料与内交联水性聚氨酯乳液原位聚合制备改性还原石墨烯/水性聚氨酯复合乳液,放入四氟乙烯模具室温干燥成膜,得到胶膜样品。利用万能材料试验机、导热系数测试仪和热重分析仪等手段研究填料质量分数对复合胶膜机械性能、导热性能和热稳定性的影响,利用扫描电镜观察胶膜的形貌,搭建热界面实验台考察其散热效果。结果表明:利用氨基化石墨烯改性水性聚氨酯,胶膜的拉伸强度、断裂伸长率、导热性能和热稳定性都能得到明显的提升。当填料质量分数为3%时,复合胶膜较纯胶膜热源温度降低了2.4℃,界面间传热效率得到提高。
Graphene oxide was aminated with 3-aminopropyl triethoxysilane to prepare modified graphene oxide after condensation reaction between silicon hydroxyl group produced by hydrolysis and oxygen-containing functional group on the surface of graphene oxide,and then diethanolamine was used for reduction to further obtain modified reduced graphene.The modification effects were analyzed by infrared spectroscopy.Using modified reduced graphene as thermal conductive filler,the modified reduced graphene/waterborne polyurethane composite emulsion was prepared by in-situ polymerization of thermal conductive filler and internal crosslinked waterborne polyurethane emulsion,and then dried into film at room temperature.The effects of filler mass fraction on the mechanical properties,thermal conductivity and thermal stability of composite adhesive film were studied by universal material testing machine,thermal conductivity tester and thermogravimetric analyzer.The morphology of adhesive film was observed by scanning electron microscope,and the thermal interface test-bed was built to investigate its heat dissipation effect.The results showed that the tensile strength,elongation at break,thermal conductivity and thermal stability of the composite film produced from modified aminated graphene/waterborne polyurethane composite could be significantly improved.When the mass fraction of filler was 3%,the heat source temperature of composite film was 2.4℃ lower than that of pure film,and the heat transfer efficiency between interfaces was improved.
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基金资助
国家自然科学基金(51206071);湖南省自然科学基金项目(2019JJ40284)
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