Properties Of Montmorillonite-Graphene Oxide Aerogel/Epoxy Composites With Low Dielectric Constant

With the development of electronic products in the direction of miniaturization and multifunction,high-performance printed circuit boards and large-scale integrated circuit microelectronics are in urgent need of epoxy resins(EP)with low dielectric constant and low dielectric loss and excellent mechanical and thermal properties.Among the inorganic nano-fillers,Montmorillonite(MTT)can effectively improve the mechanical properties of EP due to the high aspect ratio,while Graphene oxide(GO)has a significant effect on the insulation and thermal stability of EP.In recent years,the three-dimensional network structure of GO aerogel has become a hot spot due to its large specific surface area and good dispersion effect.In this paper,MMT and GO aerogels are combined and introduced into epoxy resin to prepare composite materials with low dielectric constant and excellent comprehensive performance.In this paper,GO was prepared by the modified Hummers method,and GO aerogel was obtained by freeze-drying process.In order to improve the dispersion effect of the fillers in the EP and the interfacial bonding strength with the matrix.MMT,GO and GO aerogels were modified with KH560 to obtain modified OMMT,FGO and FGOA,respectively.FGO-OMMT/EP and FGOA-OMMT/EP composites were prepared by in-situ polymerization.The effects of the same content(0.1 wt%)of FGO and FGOA on the properties of 3 wt%OMMT/EP composites and the effect of FGOA content on the properties of 3 wt%OMMT/EP composites were compared.The results shown that the FGOA prepared in this paper has a three-dimensional network structure with a pore size of about 100 um.The bonding between FGOA and OMMT occured,and the dispersion effect of composite powder was better.Adding only 0.1 wt%of FGOA or FGO can not only significantly reduced the dielectric constant and dielectric loss of the 3 wt%OMMT/EP composite,but also improved its mechanical and thermal properties,and added FGOA to reduce the material electrical constant and dielectric loss and meanwhile the improvement of mechanical and thermal properties were significant compared with FGO.When the OMMT loading was 3 wt%,the dielectric constant of FGOA-3 wt%OMMT/EP composite decreased first and then increased with the increase of FGOA content.The mechanical and thermal properties were gradually improved.Specifically,when the frequency was10~6 Hz,the 0.1 wt%FGOA-3 wt%OMMT/EP composite had a dielectric constant of3.23,which was 11.26%lower than that of pure EP(3.64).The flexural strength and impact strength of 0.4 wt%FGOA-3 wt%OMMT/EP composites reached 132.04MPa and 15.89 kJ/m2,which were 58.2%and 217.8%higher than pure EP,respectively,and around 40°C,the composite storage modulus reached 2508 MPa,which was 42%higher than pure EP.The thermal stability and thermal conductivity of all composites were slightly improved compared to pure EP.These changes in properties were closely related to the interfacial structure of the interaction between the FGOA-OMMT and the EP matrix.