Polydimethylsiloxanes silanol-terminated polymers

After separation and purification by distillation, the difimctional compound dimethyl di-chlorosilane is then allowed to react with water tQ form a hydrolyzate, which is a mixture of cyclic and linear polydimethylsiloxanes. The linear components are low-molecular weight hydroxyl (silanol) terminated polymers. 

Figure 10 Formation of linear and crosslinked polydimethylsiloxane networks. Room temperature vulcanization (RTV) is performed by reacting methoxysilyl-terminated polymer 75 and methyltrimethoxysilane 76. Hydrolysis produces transient silanols 77 and 78 whose dehydration yields silicone precursor 79. Two-part systems are based on the platinum-catalyzed addition reaction between vinyl-terminated polysiloxane 80 and polydimethylsiloxane carrying either only terminal 81 or multiple silane (Si-H) pendent groups. Silicone main chains of the resulting polymer 82 are linked through silicon-...

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