Preparation of high strength and optically transparent silicone rubber

High strength and optically transparent silicone rubber was prepared by two methods in this paper. First, the method of refractive index matching was used. Dimethylvinyl group terminated poly(dimethylsiloxane-codiphenylsiloxanes) were prepared and the effects of phenyl fraction on refractive index and optical properties of silicone elastomers were studied. The results show that addition of appropriate amounts of fumed silica treated with D-4 to the silicone elastomers (refractive index = 1.430), followed by curing produces a silicone elastomer with a tensile strength of 9.5 MPa, and a transmission value of 87%. In the second method, wet process hydrophobe silica technology was used. The factors which have effects on the size and structure of WPH silica. were discussed in details. Effects of hydrophobe agent on the hydrophobicity development were also studied. Based on the experiment data, the physical properties may be modified over a broad range by controlling the reactants. Silicone elastomers with a better transmission values can be achieved with or without index matching and the tensile strength of this cured silicone rubber was 11.5 MPa. (C) 1998 Elsevier Science Ltd. All rights reserved.