Silane-functionalized graphene oxide/epoxy resin nanocomposites: Dielectric and thermal studies

Improved dispersion of graphene oxide (GO) in the epoxy resin, as nanofiller, requires surface modification. Hence, functionalization of GO with small silane (GONSi) and bulky silane moieties (GOSi) has been carried out. Structural confirmation analysis of the prepared GO and modified forms have been performed using different analytical techniques. Cationic photocuring polymerization of pure aliphatic epoxy resin (CE) and loaded samples with GO, GOSi, or GONSi in amounts 0.5 and 1 wt % has been followed by FTIR. Loading of CE showed a passive effect for the modified filler on the conversion of the CE during photocuring, whereas the thermal stability of loaded epoxy resin is enhanced. Dielectric properties investigations revealed that the insulation feature of CE is not seriously reduced by the addition of GO or its modified forms. The secondary relaxation β process originating from the fluctuations of the side functional hydroxyl group can be described by the semi-empirical Cole–Cole function. The dielectric loss values are decreasing in the order GONSi > GOSi > GO > CE. Furthermore, it was found that the activation energy of the dynamic process is related to the conversion and to the ratio of the modified filler. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48253.