Reversible addition fragmentation chain transfer polymerization of styrene from the edge of graphene oxide nanolayers

A graphene oxide modifier containing chain transfer agent moieties (CR) was synthesized by an esterification reaction between 1,4-butanediol and 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid. CR moieties were grafted at the edge of GO in low and high graft densities to yield GCRL and GCRH respectively. Then, GCRL and GCRH were used in grafting from reversible addition fragmentation chain transfer polymerization of styrene. Grafting of CR moieties was approved by Fourier transform infrared spectroscopy, X-ray photo electron spectroscopy, and Raman spectroscopy. Expansion of graphene oxide interlayer by oxidation and functionalization processes was evaluated by X-ray diffraction. Conversion values of styrene monomer were obtained from gas chromatography. Molecular weight and PDI values of attached polystyrene chains were studied by size exclusion chromatography. Thermogravimetric analysis was also used to investigate the degradation temperatures, char contents, and graft contents. The attached modifier content in GCRH and GCRL is estimated to be 7.6 and 4.0% respectively. Scanning electron and transmission electron microscopies show that flat and smooth layers of graphite are wrinkled during the oxidation and then turned to opaque layers as a consequence of polymer grafting.