Synthesis of carbon–polyacrylate nanocomposite materials by crosslinking polymerization

Nanocomposite materials made of carbon nanoparticles dispersed in a crosslinked polymer have been produced by light-induced polymerization of a multifunctional acrylic resin containing graphite, oxidized graphite or acetylene black. Exfoliation of graphite was achieved by sonication of the filled resin, and confirmed by sedimentation analysis. Under intense illumination the solvent-free resin was transformed within a fraction of a second into a hard and tough material, at ambient temperature. The photopolymerization was followed by infrared spectroscopy and shown to proceed effectively up to 85% conversion of the acrylate double bonds. The slowing down effect of the carbon particles by screening of the UV-radiation is becoming increasingly important as the sample thickness and the filler content are increased. A redox initiator consisting of benzoyl peroxide and a tertiary amine was used to achieve a deep through-cure of thick samples, a process which was markedly accelerated in presence of acetylene black. These carbon nanocomposite materials proved to be more flexible and resistant to shocks than the neat acrylic polymer. Electrical conductivity was found in nanocomposites containing acetylene black at concentrations above 1 wt.%.