Polyblend systems of polyurethane rubber and silicone rubber in the presence of silane grafting agent

Polyurethane elastomer (AU) and silicone rubber (VMQ) form immiscible blends with a low compatibility. In order to improve the compatibility and physical properties of the blends, VMQ was first grafted with vinyl triacetoxy silane (VTAS) by using dicumyle peroxide (DCP) as a grafting initiator; subsequently, it was blended with AU. The state of cure is improved in the case of AU/grafted-VMQ blends. Physical properties like hardness, modulus and tensile strength increased for the AU/grafted-VMQ blend compared to the AU/VMQ blend. IR spectral analysis suggested the probable interaction between the grafted silicone rubber and polyurethane elastomer. High temperature DSC study showed the increment of thermal stability of AU/grafted-VMQ blend. The extraction of single phase in solvent is restricted for AU/grafted-VMQ blend, indicating the interchain crosslinking as confirmed by SEM study.