EFFECT OF SURFACTANT AND SODIUM ALGINATE MODIFICATION OF GRAPHENE ON THE MECHANICAL AND THERMAL PROPERTIES OF POLYVINYL ALCOHOL (PVA) NANOCOMPOSITES

Graphene is under intense investigation as a high performance reinforcing nanofiller for the fabrication of polymer nanocomposites. The challenge is to achieve uniform dispersion of graphene nanosheets and tailor the polymer-graphene nanosheets interface. In this regard, the graphene nanosheetshave been modified using two different non-covalent modifiers, which are sodium dodecyl sulfate (SDS) and sodium alginate (SA). The effect ofthese non-covalent modificationsof graphenenanosheets on the mechanical, thermal and crystallization behavior of polyvinyl alcohol (PVA) nanocompositeshave been studied. The results indicate that the graphenenanosheets areexfoliatedin the PVA matrix, when the graphenenanosheets are modified using SDS and SA. SDS assisted dispersion of graphene nanosheetsdepicts the intercalated state of dispersion of graphenenanosheets in the PVA matrix. This has resulted in remarkable improvement in tensile modulus and tensile strength of PVA nanocomposites containing SDS and SA modified graphenenanosheets, as compared with pure PVA and PVA/SDS-m-graphene nanocomposites. The remarkable increase in mechanical properties is due to an efficient load transfer from PVA to graphenenanosheets, as well as hydrogen bonding between PVA and SA. However,a remarkable increase in the mechanical properties of PVA nanocompositesis achieved despite the decrease in the crystallinity of PVA, revealing the reinforcing efficiency of graphenenanosheets. In addition, the thermal stability of PVA nanocomposites also increases with theaddition of a small concentration of SDS and SA modified graphene.