SYNTHESIS, MORPHOLOGICAL AND RHEOLOGICAL CHARACTERIZATION OF GRAPHENE-FILLED POLYSTYRENE NANOCOMPOSITES

425 | Page SYNTHESIS, MORPHOLOGICAL AND RHEOLOGICAL CHARACTERIZATION OF GRAPHENE-FILLED POLYSTYRENE NANOCOMPOSITES Manasi Singhi Department of Chemistry, Ambedkar Institute of Advanced Communication, Technologies and Research, Geeta Colony, New Delhi, (India) ABSTRACT Homogeneous and uniform dispersion of nanofillers in polymers has always been a challenge for the synthesis of polymer nanocomposites. The agglomeration of nanofillers adversely affects the resultant properties of composites. Keeping in view this aspect, a novel method of synthesis has been chosen for the synthesis of polymer nanocompsoites which is being presented in the present paper. A series of graphene filled polystyrene nanocomposites was prepared by changing the concentration of graphene. Ultrasonication of graphene fillers during in-situ polymerization of styrene monomer was attempted to avoid agglomeration of fillers. Nanocomposites, prepared by compression moulding, were then studied for their morphological and rheological behavior. Storage modulus, loss modulus and complex viscosity of nanocomposites were measured and results were analysed vis-à-vis concentration of graphene. A significant improvement in the rheological properties of composites was observed and attributed to the controlled and uniform distribution of graphene fillers that was confirmed through scanning electron microscopy (SEM).A theoretical analysis has been presented to explain the crossover frequency of nanocomposites. Keywords: Graphene, Polystyrene, Nanocomposites, SEM, Rheology I. INTRODUCTION Ever since its discovery, graphene (one-atom-thick planar sheet of sp 2 bonded carbon atoms) has attracted the attention of scientists and numerous attempts have been made in the last few years to exploit its beneficial properties. A large number of papers are available in the literature which mostly deals with replacing carbon nanotubes (CNTs) with graphene as fillers in polymer nanocomposites for various applications. In particular, the high aspect ratio of graphene nanosheets (which may consist of one or more graphene) has been a key factor in significantly improving the resultant properties of nanocomposites. For instance, electrical conductivity of nanocomposites improves remarkably with small loadings of GNSs. However, two major aspects have always been a serious concern. Firstly, the uniform and homogeneous dispersion of graphene, which has posed a bigger challenge and secondly, conflicting reports exist in the literature regarding the optimum concentration of graphene required for achieving the desired properties [1-12]. Thus, in this work, it was aimed to synthesize a series of graphene-polystyrene nanocomposites by changing the concentration of

SYNTHESIS, MORPHOLOGICAL AND RHEOLOGICAL CHARACTERIZATION OF GRAPHENE-FILLED POLYSTYRENE NANOCOMPOSITES

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graphene

polystyrene

nanocomposites

sem

rheology