Effects of octamaleamic acid-POSS used as the adhesion enhancer on the properties of silicone rubber/silica nanocomposites

In this paper, the addition of octamaleamic acid-POSS (OM-POSS) nanoparticles to silicone rubber (SR) composites were investigated for enhancing the adhesion properties to reinforcing fibers. The content of OM-POSS was examined as the experimental parameter. The reference was a 5-phr silica filled SR compound. The peroxide curing characteristics of composites was determined by means of differential scanning calorimeter (DSC) and moving die rheometer. It was found that OM-POSS retarded the curing time and decreased the crosslinking density. DSC analysis indicated that the crosslinking reaction started at lower temperature as the OM-POSS concentration increased. The dynamical mechanical analysis (DMA) results showed that the melting point decreased by the addition of OM-POSS content. The crystallinity of SR decreased with increasing OM-POSS content. The thermal stability of SR composites obtained from TGA apparently improved by the addition of OM-POSS. The SEM and TEM pictures showed that the OM-POSS distribution was homogeneous at lower contents, but some agglomerates were seen when the content of OM-POSS increased. Tensile tests exhibited that comparable mechanical properties were achieved for SR/OM-POSS composites with respect to reference composite. It was demonstrated by H-adhesion tests that the utilization of OM-POSS in the SR composites improved the adhesion of the matrix to Rayon fiber.