Immobilization of Functionalized Silica Nanoparticles to Polystyrene-block-polybutadiene-block-Polystyrene via Chlorination: Interaction Parameters and Key Properties

Alternate copolymers of styrene and butadiene like styrene butadiene rubber (SBR) and the corresponding block copolymer polystyrene-block-polybutadiene-block-polystyrene (SBS) have different sets of applications either in making tire/conveyor belts or in coatings and adhesives. Although there are several reports of composites of SBR, there are only a handful of reports of composites of SBS with silica nanomaterials and detailed studies. In this paper, we report a detailed comparative study of composites of functionalized or nonfunctionalized SBS and silica nanoparticles. Functionalization involved polar groups in both SBS and silica in anticipation of better interactions leading to improvement of properties. Significant interactions were seen, as indicated by NMR spin-relaxation (T2 and T1) analysis and small-angle X-ray scattering experiments and further corroborated by electron microscopic data. Key mechanical properties like abrasion resistance and hardness improved substantially after composite formation.