A graphene hybrid material functionalized with POSS: Synthesis and applications in low-dielectric epoxy composites

A graphene hybrid material functionalized with octa-aminophenyl polyhedral oligomeric silsesquioxanes (OapPOSS) was synthesized and a new application of OapPOSS-g-GO was reported. The structure of OapPOSS-g-GO was confirmed by TEM, HRTEM, SEM, FTIR, XRD, Raman and Uv–vis. The OapPOSS functionalized graphene nanosheets can disperse homogeneously in various organic solvents. Moreover, the thermal stability of the OapPOSS-g-GO was improved and the initial thermal decomposition temperature was significantly increased from 75.2 to 394.5°C compared to that of pure GO by thermal gravimetric analysis (TGA). With the incorporation of only 0.2wt% OapPOSS-g-GO, at 104Hz the dielectric constant and dielectric loss of OapPOSS-g-GO/epoxy composites dropped by 9% and 49% compared to the neat epoxy composites. This dramatically reduced dielectric constant and dielectric loss can be explained in terms of cage silsesquioxane cores of the OapPOSS and the movement of OapPOSS and polymer chains being limited by GO nano-platelet, resulting in a loose and the immobile epoxy structure. This approach provides a strategy to reduce the dielectric constant of epoxy composite materials with ultra-low filler content.