There are significant differences in low temperature performance between phenyl vinyl silicone (usually refers to methyl phenyl vinyl silicone rubber, referred to as phenyl silicone rubber) and dimethyl silicone rubber (referred to as methyl silicone rubber). The following is a detailed comparison of the low temperature performance of the two:

1. Low temperature performance of dimethyl silicone rubber
Temperature range: Dimethyl silicone rubber can maintain good elasticity in the range of -60~250℃. However, its vulcanization activity is low, high temperature compression permanent deformation is large, and it is not suitable for the preparation of thick products, because thick products are difficult to vulcanize and the inner layer is prone to blistering.
Performance at low temperature: Although the glass transition temperature of dimethyl silicone rubber is very low (about -125~-130℃), it will gradually lose its elasticity due to strong crystallization when working for a long time at low temperature, so its ability to work for a long time at low temperature is limited.

2. Low temperature performance of phenyl vinyl silicone
The influence of phenyl content: The performance of phenyl vinyl silicone varies with the content of phenyl in the molecular chain. Generally speaking, an increase in phenyl content will improve the flame retardancy and radiation resistance of silicone rubber, but will reduce its low temperature resistance. However, within a specific phenyl content range (such as 5%~10%), phenyl vinyl silicone can show excellent low temperature resistance.
Performance at low temperature: Low phenyl silicone rubber (phenyl content is 5%~10%) has unique cold resistance and can still maintain the elasticity of rubber at -70~-100℃. It is the best low temperature performance among all rubbers. Although the low temperature resistance of medium phenyl silicone rubber (phenyl content is 10%~20%) is slightly inferior to that of low phenyl silicone rubber, it still has excellent flame retardant properties and can self-extinguish once it catches fire.
Non-crystallization: Medium phenyl silicone rubber is a non-crystalline silicone rubber. It is not easy to crystallize at low temperature, so it can maintain good elasticity. Although low phenyl silicone rubber also has certain cold resistance, its crystallization melting temperature is low, and it may gradually lose its elasticity if it works at low temperature for a long time.

III. Comparison summary
Low temperature resistance: Under the same temperature conditions, the low temperature resistance of phenyl vinyl silicone (especially low phenyl silicone rubber) is significantly better than that of dimethyl silicone rubber. Although dimethyl silicone rubber can maintain elasticity in a wide temperature range, it is easy to crystallize and lose elasticity when working for a long time at low temperature.
Application field: Phenyl vinyl silicone is particularly suitable for occasions that need to work at extremely low temperatures, such as aerospace, military industry and other fields due to its excellent low temperature resistance. Dimethyl silicone rubber is more widely used in general industrial fields.

In summary, phenyl vinyl silicone is superior to dimethyl silicone rubber in low temperature performance, especially in occasions that require low temperature resistance. However, in specific applications, it is necessary to select the appropriate type of silicone rubber according to actual needs.