On Styrene-Block Isoprene-Block Styrene Block Copolymers Filled with Carbon-Coated Ni Nanoparticles

Polymer-based nanocomposites have new or modified features produced by the loading of the matrix with nanoparticles, refining the match between intrinsic properties and required performance. Nanocomposites were obtained by dispersing various amounts of carbon-coated nickel nanoparticles (CNi) within the matrix of a polystyrene-block isoprene-block polystyrene (PS-bPI-bPS) block copolymer. The average size of CNi was about 20 nm, with a carbon coating thickness of about 1 nm. The polymeric matrix was PS-bPI-bPS with 17 % polystyrene and an average molecular mass of about 17,000. Wide-Angle X-ray Scattering, Small Angle X-Ray Scattering, and Small Angle Neutron Scattering data are reported. Complementary Raman and FTIR measurements focused on the specific vibrations of the matrix and on the changes generated by the addition of the nanofiller are analyzed. This research centers on the self-assembly of the PS-bPI-bPS matrix as well as on the interactions between the polymeric matrix and the nanofiller. The polymer matrix consists of a continuous and soft phase of polyisoprene that incorporates harder polystyrene cylinders with an estimated diameter of about 150 nm. A gradual decrease of the fraction of self-assembled polystyrene and polyisoprene blocks as the concentration of nanoparticles was increased was noticed. Differential thermal analysis and differential scanning calorimetry (DSC) monitored the phase transitions in the PS-bPI-bPS) block copolymers and their thermal stability.