Properties of Waterborne Polyurethane/Functionalized Graphene Sheet Nanocomposites Prepared by an in situ Method

Nanocomposites of waterborne polyurethane (WPU) with functionalized graphene sheets (FGS) were prepared by an in situ method. The morphology observed by transmission electron microscopy showed that pristine nanosize FGS can be finely dispersed in a WPU matrix so that it can efficiently improve the conductivity of WPU. The modulus improvement by the reinforcing effect of FGS was more evident than our previous results of nanocomposites prepared by a physical mixing method, showing that the interactions between FGS and WPU were improved when made by the in situ method. In addition, the FGS enhanced the crystallization of the soft segment of WPU evidently; however, it reduced that of the hard segment. The thermal degradation of WPU was accelerated by FGS.