Effect of surfactant treated boehmite nanoparticles on properties of block copolymers

The effectiveness of reinforcement of a polymer is known to depend on the strength of the interfaces between the reinforcement and the matrix. We have used polystyrene and a styrene-butadiene-styrene (SBS) copolymer as matrixes and ceramic boehmite gamma-AlO(OH) as reinforcement. We have applied boehmite both untreated and treated with sulphonic acid based surfactants with different alkyl groups. As expected, the coupling agents improve the adhesion between the polymers and the ceramic filler. The presence of boehmite and treatments affect the glass transition temperatures determined by dynamic mechanical analysis, nanoindentation hardness h(nanoindent) as well as Vickers microhardness h(Vickers). For SBS and SBS containing composites, the h(nanoindent)/ h(Vickers) ratio is a constant.