Do you know silicone rubber? Silicone rubber refers to […]
Do you know silicone rubber?
Silicone rubber refers to the rubber whose main chain is composed of alternating silicon and oxygen atoms, and two organic groups are usually connected to the silicon atom. Ordinary silicone rubber is mainly composed of silicone chain units containing methyl groups and a small amount of vinyl groups. The introduction of phenyl can improve the high and low temperature resistance of silicone rubber, and the introduction of trifluoropropyl and cyano groups can improve the temperature and oil resistance of silicone rubber. Silicone rubber has good low temperature resistance and can generally still work at -55°C. After the introduction of phenyl, it can reach -73°C. The heat resistance of silicone rubber is also very outstanding. It can work for a long time at 180 °C, and can withstand a few weeks or longer even if it is slightly higher than 200 °C. It can withstand high temperatures above 300 °C instantaneously. Silicone rubber has good air permeability and oxygen transmission rate is the highest among synthetic polymers. In addition, silicone rubber has outstanding properties of being physiologically inert and not causing coagulation, so it is widely used in the medical field.
Silicone rubber is divided into thermal vulcanization type (high temperature vulcanization silica gel HTV) and room temperature vulcanization type (RTV). Among them, the room temperature vulcanization type is divided into polycondensation reaction type and addition reaction type. High temperature silicone rubber is mainly used to manufacture various silicone rubber products, while room temperature silicone rubber is mainly used as adhesive, potting material or mold. The thermal vulcanization type has the largest amount, and the thermal vulcanization type is divided into methyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ, the largest amount and product brand), and methyl vinyl phenyl silicone rubber PVMQ (low temperature resistance, radiation resistance). ), and others include eye silicone rubber, fluorosilicone rubber, etc.