Effect of oxygen functionalities of graphene oxide on polymerization and thermal properties of reactive benzoxazine nanocomposites

Herein, we report the effect of oxygen functionalities of graphene oxide on thermal activated polymerization and thermal properties of reactive benzoxazine nanocomposites. The numbers of oxygen moieties of graphene oxide (GO) are controlled by hydrothermal reduction. The polymerization behavior of benzoxazine monomer (BA-a) is studied by Fourier transform infrared spectroscopy, differential scanning calorimetry and rheological analysis. It is hypothesized that the GO not only exhibits accelerated effect on the polymerization of the BA-a, but also the oxygen moieties such as carboxyl groups of GO interact with the benzoxazine polymers, leading to several orders of magnitude increase in the chemoviscosity and modulus of composite system. Thermal conductivity of poly(BA-a)/GO composite increases from an initial value of ∼0.27 W/mK to 0.47 W/mK as the loading increases from 1 wt% to 6 wt% (enhancement factor up to 176%). Moreover, the nanocomposites display enhanced initial decomposition temperature and char yields as the degree of GO reduction increases.