Viscoelastic Behavior, Curing and Reinforcement Mechanism of Various Silica and POSS Filled Methyl-Vinyl Polysiloxane MVQ Rubber

The role of Aerosil silicas, A90, R812, R812s on the complex dynamic viscosity η* of methyl-vinyl polysiloxane MVQ at processing temperature 80°C was analyzed based on experiments with a torsional rheometer Rubber Process Analyzer RPA. The influence of surface area and surface activity on the Payne’s effect was determined by oscillating rheometer Ares G2. The decrease in complex modulus G* by increasing strain for silicas R812, R812s was mostly due to the breaking down of filler-filler networking, the modification of surface led to better processability resulting in the increase of tensile strength TS, from 0.42 MPa unfilled silicone to 9.31 MPa MVQ containing R812. Higher surface activity of silica A90 caused a decrease in filler networking due to a better filler-polymer interactions, which resulted in the increase of the percentage of non-covalent crosslinks determined for samples treated with ammonia. The decrease of static water contact angle θ of silicone rubber after incorporation of A90 was observed. Influence of allylisobutylPOSS on curing, crosslink density, static and dynamic behavior of silicone rubber was considered.