Abstract
Nanocomposite materials based on copolymers of styrene and n-butyl methacrylate with either graphene oxide (GO) or functionalized graphene oxide (F-GO) were synthesized using the in-situ bulk radical copolymerization technique. Reaction kinetics was studied both experimentally and theoretically using a detailed kinetic model also taking into account the effect of diffusion-controlled phenomena on the reaction kinetic rate constants. It was found that the presence of GO results in lower polymerization rates accompanied by the synthesis of copolymers having higher average molecular weights. In contrast, the presence of F-GO did not seem to significantly alter the conversion vs time curves, whereas it results in slightly lower average molecular weights. The first observation was attributed to side reactions of the initiator primary radicals with the hydroxyl groups on the surface of GO, resulting in lower initiator efficiency, whereas the second to grafted structures formed from copolymer macromolecules on the F-GO surface. The copolymerization model predictions including MWD data were found to be in satisfactory agreement with the experimental data. At least four adjustable parameters were employed and their best-fit values were provided.
Highlights
Graphene is believed to be the “thinnest and strongest material known so far” and has recently attained significant research interest due to its exceptional mechanical, electrical, thermal and optical properties
It is easier to get graphene oxide (GO) sheets from the exfoliation of graphite oxide. The latter can be produced from the oxidation of graphite using concentrated acids in the presence of strong oxidants and consists of many oxygen-containing groups, such as carboxyl, hydroxyl and epoxy groups in the basal planes and edges
The copolymer with the higher amount of styrene presents a behavior similar to that of the PS homopolymer, whereas the copolymer reach in BMA shows a conversion curve in-between the two corresponding homo-polymers
Summary
Graphene is believed to be the “thinnest and strongest material known so far” and has recently attained significant research interest due to its exceptional mechanical, electrical, thermal and optical properties. It has a Young’s modulus near 1 TPa. It has a Young’s modulus near 1 TPa These properties make graphene one of the most popular nano-additives for the development of functional and structural graphene-reinforced polymer nanocomposites [1]. It is easier to get graphene oxide (GO) sheets from the exfoliation of graphite oxide The latter can be produced from the oxidation of graphite using concentrated acids in the presence of strong oxidants and consists of many oxygen-containing groups, such as carboxyl, hydroxyl and epoxy groups in the basal planes and edges. Functionalized graphene oxide (F-GO) could be produced by reacting the surface hydroxyl groups of GO with a silane which has methacrylate groups [2,3,4,5,6]
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