Graphene-based masterbatch obtained via modified polyvinyl alcohol liquid-shear exfoliation and its application in enhanced polymer composites

A simple and inexpensive method for the production of graphene-based masterbatch via polymer-assisted shear exfoliation of graphite in water was comprehensively investigated. In detail, a modified polyvinyl alcohol (mPVOH) characterized by surface energy comparable with that of graphene was used as surfactant for the production of graphene-like particles. The proposed approach allowed a yield in graphene-like particles higher than that obtained by using common surfactants, along with a narrower size distribution. A mPVOH-masterbatch containing 4.38 wt% of graphene-like particles was produced by removing the aqueous solvent from a dispersion and directly used for production of polymer nanocomposites by melt processing. Films prepared by blending the masterbatch with polyvinyl alcohol in order to have a graphene-like particles content equal to 0.3 wt% showed a 78% reduction in water permeability and a 48% increase in storage modulus as compared with pristine polymers. Improved barrier properties were also observed for polylactic acid (PLA) and low-density polyethylene (LDPE)-based composite films, whereas an increment of about 520% in the storage modulus was observed for the composite obtained with PLA. The obtained results are very relevant and the proposed process will open up a new pathway for using graphene-based masterbatch in the packaging industry.