The so-called smell: smell = gas + taste. Gas is gas, volatile matter. It is a substance, usually small molecules, so it is easy to turn into gas. Taste is sensory perception, which is equivalent to sensor. It refers to the change of biological physical quantity (physical quantity can be electricity, magnetism, light, length or volume, ion flow, molecular flow, etc.) after molecules act on the surface of sensory (sensor). The generated signal is transmitted to CPU (brain) through nerve. Therefore, smell does not refer to a substance, but the process of interaction between substances.

Generally speaking, silicone rubber can be divided into organic silicone rubber and inorganic silicone rubber according to its properties and components. According to its composition and shape, it is divided into extruded silicone rubber and molded silicone rubber. Inorganic silicone rubber is a highly active adsorption material, which is usually prepared by the reaction of sodium silicate and sulfuric acid, aging, acid bubble and a series of post-treatment processes. Silicone rubber is an amorphous substance, and its chemical molecular formula is msio2.nh2o. It is insoluble in water and any solvent, non-toxic and tasteless, with stable chemical properties. It does not react with any substance except strong alkali and hydrofluoric acid. Various types of silicone rubber form different microporous structures due to different manufacturing methods. The chemical composition and physical structure of silicone rubber determine that it has many characteristics that are difficult to be replaced by other similar materials: high adsorption performance, good thermal stability, stable chemical properties, high mechanical strength and so on. Organic silicone rubber is a kind of organic silicon compound, which refers to the compound containing Si-C bond and at least one organic group is directly connected with silicon atom. It is customary to treat those compounds that connect organic groups with silicon atom through oxygen, sulfur and nitrogen as organic silicon compounds. Among them, polysiloxane with siloxane bond (- Si-O-Si -) as skeleton is the most numerous, most deeply studied and most widely used type of silicone compounds, accounting for more than 90% of the total dosage. It is common to extrude silicone rubber, such as the sealing ring on household rice cooker, which is called silicone rubber sealing ring of rice cooker. Molded silicone rubber is more complex and irregular in shape, including silicone rubber bowl, silicone rubber ice lattice, silicone rubber cake mold and so on.