Physical and mechanical properties of poly(methyl methacrylate) -functionalized graphene/poly(vinylidine fluoride) nanocomposites Piezoelectric β polymorph formation

Poly(methyl methacrylate) -functionalized graphene (MG) is prepared from graphene oxide (GO) using atom transfer radical polymerization (ATRP) and reducing with hydrazine hydrate PMMA causes an Increase of height of MG sheet for polymerization of MMA at side and basal planes MG layers become thinner for exfoliation during composite formation Graphene sheets enhance piezoelectric beta-polymorph PVDF formation MG sheets nucleate PVDF crystals and a gradual decrease of a phase occurs with a concomitant rise of beta phase Thermal stability of nanocomposites increases significantly and the T-g increase is really large (21 degrees C) Storage modulus shows an increase of 124% stress at break 157% and Young s modulus 321% for 5% MG Parallel orientation of graphene sheets changes to random orientation for high graphene content It exhibits conducting percolation threshold at 3 8% MG and variable range hopping model suggests that conductivity is contributed from the intergrain tunnelling and hopping between the grains (C) 2010 Elsevier Ltd All rights reserved