石墨烯对低红外发射率聚氨酯/铝复合涂层耐温性能的影响

Effect of Graphene on Heat Resistant Properties of Polyurethane/Al Composite Coating with Low Infrared Emissivity

有机硅树脂涂层需180℃固化,才具有耐高温氧化和优异稳定的力学性能,生产中难以达到。以Al粉为颜料、聚氨酯(PU)为黏合剂、石墨烯为改性剂,采用喷涂法制备了石墨烯改性PU/Al复合涂层。利用现代表面分析技术和国家标准方法,系统研究了石墨烯改性剂对复合涂层功能及其耐温性能形貌的影响规律。结果表明:石墨烯改性剂可强化复合涂层的导热和散热效果,使其耐温性能明显增强;改性后的复合涂层热老化时颜色加深及起泡现象不明显,且在240℃以上高温热老化条件下具有更低的发射率性能,当热老化温度为250℃时,改性前后涂层的发射率分别为0.241和0.184;改性后的复合涂层保持了优异稳定的力学性能,经不同温度热老化后的硬度、附着力和耐冲击强度可分别保持在3 H,1级和500 N·cm,能很好地满足实际工程的应用要求。

Graphene modified polyurethane（ PU）/Al composite coating was prepared by spraying method with Al powders as pigments, PU as binders and graphene as modifiers. The influences of graphene modification on the functional characteristics, heat resistant properties and morphologies of the coatings were systematically investigated by surface analytic method and national registration method. Results showed that gra-phene modification could improve the heat corrosion by enhancing the heat conduction of composite coating and heat dissipation effect. The composite coating modified with graphene presented less color deepening and bubbling phenomenon due to heat aging, and the coating treated under high temperature aging conditions with more than 240℃ possessed lower emissivity. When the heat aging temperature was 250℃, the emissivity values of coatings before and after modification were 0.241 and 0.184, respectively. Moreover, the composite coating after modification could keep excellent and stable mechanical properties, and after heat ageing treatment, the hardness, adhesion and impact strength restrained 3 H, 1 grade and 500 N·cm, respectively, which could meet the requirements of practical engineering applications.