A. The raw materials of silica gel are generally gel-like, a bit similar to plasticine, colorless, translucent, and tasteless.

B. Its main feature is high temperature resistance (maximum 300℃) and low temperature resistance (minimum -100℃). It is currently the best cold and high temperature resistant rubber; at the same time, it has excellent electrical insulation and high stability to thermal oxidation and ozone. , Chemically inert. The disadvantage is that the mechanical strength is low, oil resistance, solvent resistance, acid and alkali resistance are poor, it is difficult to vulcanize, and the price is more expensive. Operating temperature: -60℃～＋200℃. The above is the description of silicone rubber in the manual.

C. Operating temperature: As mentioned above, it is generally set at -40°C-200°C, and can reach 230°C in a short time.
　
D. Aging problem:
The oil resistance, acid and alkali resistance are poor, and it has little to do with the stress.
　　
E. Bonding problem: Before surface treatment, in addition to using silicone products as adhesives to bond with silicone parts, the adhesion to other parts must be surface activated, and the glue surface can be vulcanized before it can be adhered firmly. Any substance that can react with rubber or cross-link it is collectively referred to as a vulcanizing agent, also known as a cross-linking agent. There are many types of vulcanizing agents, and they are increasing. The vulcanizing agents that have been used include sulfur, selenium, tellurium, sulfur-containing compounds, metal oxides, peroxides, resins, quinones, and amines.

F. Material hardness: The hardness of rubber parts can be selected between 10 degrees and 80 degrees in theory in the domestic market according to the Shore hardness. The ones that can be easily found are generally between 20 degrees and 70 degrees, and the most commonly used ones are between 40 and 50 degrees.