Additive liquid silicone rubber is a three-dimensional network polymer obtained by using ethylene based silicone oil as the base polymer and hydrogen containing silicone oil as the crosslinking agent. Under the action of a catalyst, it is vulcanized and crosslinked through a hydrogenation addition reaction.
Vulcanization principle of additive liquid silicone rubber
The vulcanization of additive liquid silicone rubber can be classified into three types: free radical addition mechanism, ion addition mechanism, and coordination addition mechanism. Due to the low energy of Si-H bonds, under the catalysis of free radical or ion active species, it can promote the vulcanization reaction between Si-H bonds and ethylene double bonds. However, this method cannot avoid the side reaction of ethylene double bond self polymerization, and its use is limited by many factors. The vulcanization reaction using transition metal complexes (such as platinum, rhodium, palladium, nickel, etc.) as catalysts has the characteristics of mild reaction conditions, high yield, and easy control of reaction rate, which is currently the main way of vulcanization. The sulfidation reaction using transition metal complexes as catalysts has a catalytic mechanism of coordination addition, which includes typical steps such as ligand coordination and dissociation, ligand displacement, oxidative addition and reduction elimination, insertion reaction and anti insertion. Currently, platinum complex catalyst systems are the most widely used and extensively studied.
Regarding silicone rubber, please check the details:
High Strengh Liquid Silicone Rubber IOTA 28-Series
