The thermal immobilization of hydroxy‐terminated silicone phases in high‐temperature‐silylated glass capillaries. A study of reaction mechanisms

Differently pretreated glass capillaries were coated with hydroxy‐terminated methyl or methyl‐phenyl polysiloxane gum phases and cured at 340–360°C for several hours. The volatile reaction products formed during the baking procedure were analyzed and the retention behavior of various polar test compounds were investigated both before and after the heat treatment. The findings were used to establish a reaction scheme which explains crosslinking and surface bonding of hydroxy‐terminated silicone phases in high‐temperature‐silylated glass capillaries. The principle has been extended to the immobilization of common endcapped silicone phases by mixing them with hydroxy‐terminated phases.