PVC/rice straw/SDBS-modified graphene oxide sustainable Nanocomposites: Melt mixing process and electrical insulation characteristics

Abstract

The incorporation of nanomaterials in the mixing process of polymers can effectively improve the melt mixing rheology of composites. This fact can be employed to control the morphology of sustainable composites comprised of incompatible ingredients such as natural fibers and polymers. The conventional solution to the incompatibility of natural-fiber fillers and polymers is to surface modify the natural filler. In this work, the role of graphene oxide and surface-modified graphene oxide nanosheets on the mixing rheology of a PVC/rice straw system are studied and impacts these nanosheets have on the viscosity of this sustainable system are used to reduce the morphological imperfections. The introduction of either graphene oxide or sodium dodecylbenzenesulfonate (SDBS)-modified graphene oxide nanosheets increased the melt mixing viscosity of PVC/rice straw compounds. Such a change in the melt mixing rheology of compounds resulted in an improvement in the morphological and structural characteristics. When only 1 phr SDBS-modified graphene oxide nanosheets were introduced in a PVC system filled with 15 phr rice straw fibers, more than 23 and 41% enhancement in the tensile ultimate strength of the system is achieved, compared to the neat PVC and the PVC/15 phr rice straw composite, respectively. Moreover, dynamic-mechanical results confirm that the incorporation of 1 phr SDBS-modified graphene oxide nanosheets resulted in more than 7% reduction in the damping peak intensity of the system, suggesting the formation of interactions between system ingredients. The electrical conductivity of the fabricated sustainable PVC/rice straw/SDBS-modified graphene oxide nanocomposite is in the range of 10−9–10−5 S/m, suggesting it can be a good candidate for insulating applications.