A novel reinforcing filler: application to addition-type liquid silicone rubber adhesive system

A novel addition-type liquid silicone rubber (AL-SR) adhesive has been prepared by incorporation of organic montmorillonite (OMMT). Physico-mechanical properties, such as adhesion, tensile strength and thermal stability, were investigated and compared to aerosilica (also known as pyrogenic silica) filled systems. Results showed that the properties of AL-SR containing 1 phr OMMT were nearly equal to that of the AL-SR containing 3 phr aerosilica, due to exfoliation of OMMT in the system. The structure of the AL-SR/OMMT adhesives was analyzed by wide angle Xray diffraction (WAXD), Fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). Results showed that OMMT layers in the AL-SR adhesives were in the nanometer scale and the molecular structure of AL-SR was disturbed by the presence of OMMT, which was due to the reaction between the monomers and the intercalation agent. The nano-reinforcing effect caused by the exfoliated silicate layers may reduce the amount and size of voids during tensile drawing, and thus increase the length of the crack path in their vicinity, which is regarded as the adhesion mechanism for the OMMT-reinforced AL-SR systems.