Controlled/Living Radical Copolymerization of Styrene and Methyl Methacrylate in Aqueous Dispersed Media: Synthesis and Characterization of Nanocomposite

Stable latexes of poly (styrene-co-methyl methacrylate) /clay nanocomposites were synthesized by in-situ reverse atom transfer radical polymerization at 90 °C and in miniemulsion system. Miniemulsion polymerization has been employed for its abundant advantages to encapsulate inorganic materials، simple nucleation step، and elimination of organic solvents. Final monomer conversion was determined by gravimetric method. Droplets and particles size distribution were obtained by using dynamic light scattering (DLS) analysis. Also، number and weight average molecular weight and polydispersity indexes of the samples were also evaluated by GPC method. In addition، the PDI value of the neat polymer was smaller than the extracted polymer from nanocomposites and in the case of nanocomposites it increased by increasing nanoclay content. Mole ration and fractional conversion of each monomer in copolymer chains were estimated by using 1H NMR spectroscopy. XRD patterns displayed no peak in in-situ synthesized nanocomposites which indicates an exfoliated structure of all the nanocomposites prepared by this method. FTIR spectra indicate successfully loading of nanoclay in the copolymer matrix. SEM micrographs presented a monodisperse distribution of spherical shape particles of poly (styrene-co-methyl methacrylate) /clay nanocomposite with a size in the range of around 200 nm.