silicone rubber has excellent high and low temperature resistance, ozone resistance, oxygen resistance, light resistance and weather aging resistance, excellent electrical insulation performance, special surface performance, physiological inertia and high permeability, so it is widely used. However, the tensile strength and tear strength of silicone rubber are low, the acid and aChinaali resistance is poor, and the processing performance of complex products is also poor. In recent years, many countries in the world have carried out a lot of improvement research work and achieved some results.
(1) A new polymer (blend) was obtained by copolymerization (blending) of organosilicon with other monomers or polymers. For example, the block copolymer of silicone and polycarbonate can be used as a selective permeable membrane; the characteristics of the blends of silicone rubber and ethylene propylene rubber are between those of silicone rubber and ethylene propylene rubber; the blends of silicone rubber and Eva have excellent physical properties, electrical properties, high temperature aging resistance and thermal shrinkage, and can be endowed with excellent flame retardancy after proper coordination. High temperature resistant silicone rubber and high tensile strength PMMA were used to fabricate interpenetrating polymer mesh. The strength of silicone rubber and heat resistance of PMMA were improved. The mechanical and elastic properties of silicone network were improved by synthesizing PDMS / PS IPN.
(2) By improving the matching technology, new varieties of silicone rubber with good properties of high strength, high tear resistance, low compression deformation, high temperature resistance, ultra-low temperature resistance, flame retardant, heat conduction and heat shrinkable silicone rubber were developed.
Pure silicone rubber products do not have the mechanical strength required for most applications and therefore need to be enhanced. The traditional reinforcement method is to add reinforcing filler before the curing of silicone rubber, and then mix and vulcanize. However, it is time-consuming, energy consuming, polluting the environment, and it is difficult to control the dispersion and aggregation of fillers in the rubber compound. The results show that silica, titanium dioxide and ferrite, zeolite and alumina have good strengthening effect on silicone rubber.
(3) In terms of improving processing performance, silicone rubber without secondary vulcanization, granular silicone rubber (also known as powder rubber) and liquid silicone rubber injection molding system were developed based on the catalytic addition reaction between vinyl polysiloxane and hydrosiloxane. The putty type mold making silicone rubber with good thixotropy, excellent construction performance and easy to use was developed by using addition molding two-component system.