Mixed rubber is a mixture of siloxane, its molecule belongs to the chain-like spiral structure, weight probably in $number million MPa. The viscosity is directly related to the molecular weight. The molecular weight can be measured by using a black viscometer, which is probably called the viscosity-homogeneous molecular weight. On the reinforcement mechanism of fillers, as far as I know, the Earth people have not completely understood. Probably the filler nano-scale SiO2 powder (SiO2 powder) evenly distributed in the raw rubber, forming a similar crystal structure, SiO2 particles on the surface of hydroxyl and raw rubber SI bond formation hydrogen bond, each SiO2 particles as a core, in all directions out of the hydrogen bond and rubber molecules linked to the chain, countless such structures, and add some other additives, the composition of high viscosity high-performance mixed rubber. and general silicone rubber (quality) can be similar. As the "Silicone rubber" Baidu Encyclopedia said, silicone rubber has excellent heat resistance, cold resistance, dielectric, ozone resistance and atmospheric aging performance, silicone rubber outstanding performance is the use of a broad temperature, can be -60 (or lower temperature) to Porter 250 (or higher temperature) long-term use. As to which sex (quality) is superior, it is determined by the type of raw rubber and filler and auxiliaries used.