微胶囊化石墨烯/硅橡胶泡沫电介质材料的制备及介电行为

以苯乙烯马来酸酐共聚物(SMA)为乳化剂、三聚氰胺甲醛树脂(密胺树脂,MF)为壁材、片状石墨烯(GE)为芯材,通过原位聚合法制备了包覆的石墨烯“微胶囊”,并以微胶囊作为填料,双组分室温硫化泡沫硅橡胶(RTVSR)作为基体,通过室温硫化(RTV)硅橡胶制备具有泡孔结构的电介质复合材料。提出了对石墨烯进行微胶囊化包覆的制备新工艺,讨论了超声分散功率、石墨烯与壁材的用量比例对微胶囊形貌和包覆效果的影响,并比较了包覆前后、发泡前后电介质复合材料的介电性能。研究结果表明,石墨烯与壁材质量比为1∶100、超声功率为840 W时制备的分散液较稳定、石墨烯的表面附着物较多;同时包覆(微胶囊化)能减少石墨烯发生团聚,0.3 g微胶囊填量下,包覆后的微胶囊石墨烯/泡沫电介质材料的介电常数是包覆前石墨烯/硅橡胶电介质材料的2.45倍,而介电损耗比石墨烯/硅橡胶复合材料还低,只有0.002,同时泡孔的存在有利于提升复合材料的介电性能。

Preparation of Encapsulated Graphene/Foam Silicone Rubber Dielectric Composite and Its Dielectric Behavior

Using styrene maleic anhydride copolymer(SMA) as the emulsifier,melamine formaldehyde resin(melamine resin,MF) as the wall material,and flake graphene(GE) as the core material,the coating was prepared by in-situ polymerization.Using graphene microcapsules as fillers,two-components vulcanized silicone rubber(RTVSR) as the matrix and vulcanization(RTV)silicone rubber was used to prepare a dielectric composite material with bubble pore structures at room temperature.A new process for the preparation of microencapsulation and coating of graphene was proposed.The ratio of ultrasonic dispersion power,graphene,and wall material,the effect on microencapsulation appearance,and coating effect were discussed.The dielectric properties of dielectric composite materials before and after coating and foaming were compared.The results show that the ratio of graphene to wall material mass is 1:100,the dispersion prepared with ultrasonic power of 840 W is more stable,and the surface attachment of graphene is more attached.Meanwhile,the coating(micro encapsulation) can reduce the occurrence of graphene congregation.Using 0.3 g microcapsule filling,the dielectric constant of the coated microcapsule graphene/foam dielectric material is 2.45 times that of the pre-coated graphene/silicone rubber(SR) dielectric material.And the dielectric loss is higher than that of graphene/Silicone rubber(SR) composite materials which remains low,only 0.002.The presence of bubble pores is conducive to improving the dielectric properties of composite materials.