Mechanical Property Enhancement of PVP-PVA Nanocomposite by Graphene Oxide

Abstract

Graphene, is the building block of many carbon forms, including graphite, carbon nanotubes and Buck-minster fullerenes. It has honey-comb lattice structre with an atomic layer of sp2bonded carbon atoms. Its excellent properties for example, like Youngs modulus is about 1 TPa, breaking strength is about 140 GPa, thermal conductivity is about 5000 Wm-1K-1, and high specific surface area of about 2650 m2g-1.One of the most important application of graphene is in the fabrication of layered polymer nano-composites. Its unique two dimensional morphology provides high available surface area with very small thickness(in nano size) which can be exploited in load bearing, electrical, and barrier applications. However, the reinforcing agents and their types, considerably enhance crystallinity, microstructure, and glass transition of the composites. Therefore, underpinning the processing-microstructure-property relationship in these materials is very important. The easier route of graphene production is through the top-bottom approach, where graphene oxide (GO) is synthesized by chemical exfoliation method followed by suitable reduction of GO to graphene. GO can hold various oxygen containing functional groups that make it easily mixed in nonpolar solvents. Subsequently, by different chemical treatments, few of those functional groups can be removed, and few others can be added/created, and the layer-matrix attachment can be done. The current work focus on the approaches to strengthen the matrix-reinforcement interface by various types of amines, resulting in unbelievably ultra-strong and ultra-tough PVA and PVP nanocomposites. The enhanced mechanical properties were investigated by tensile testing of different graphene oxide samples and chemically reduced graphene samples(reduced by TEA and TEOA).It has been confirmed that the reduced graphene sample shows better elastic properties compare to GO based polymer composites.