Research of the synthesis and film performance of silica/poly(St-BA-MPS) core-shell latexes obtained by miniemulsion co-polymerization

Abstract

Colloid silica nanoparticles were hydrophobic modified by γ-methacryloxypropyl trimethoxysilane (MPS) for the encapsulation into polymer. The alkoxysilane-functionalized core-shell latexes were successfully synthesized via miniemulsion copolymerization of the butyl acrylate, styrene with MPS as the functional monomer in the presence of the modified silica. When these latexes dried at room-temperature, the post-cross-linking occurred due to the alkoxysilane groups on the particle surface and lead to the formation of the films. The morphology of the nanocomposite latexes and the mechanical properties, thermal properties, fire-resistant, optical properties and micro-structure of the resulted films were characterized and discussed. Scanning electron microscope result showed most of the nanoparticles dispersed homogeneously in the polymer matrix when the content of MPS-silica was 10%. However, when the content of MPS-silica nanoparticles was beyond 10%, the aggregation of the nanoparticles became obvious. The tensile test showed that the stress at break increased a lot with the increase of silica content. The thermal and fire-resistant behaviors of the nanocomposite films were improved greatly by the incorporation of silica particles. The optical test showed that the hybrid film was comparable to the pure polymer film at around 84% transmittance.