| Abstract: | The interaction of silica and oligomeric methylsiloxanes, methylsilicone oil as well as silicone gum at elevated temperature was studied. It was found that a reaction takes place between surface silanols and octamethylcyclotrasiloxane (D4) above 180°C. Part of the methylsiloxane replaces the surface silanols forming loops with the surface, while the other part is redistributed to its neighboring homologoues. The methylsiloxy surface groups thus formed can undergo further reaction with the other methylsiloxanes above 250°C. Methylsilicone oil behaves similarly. The reaction with silicone gum was demonstrated by the formation of “chemically bound rubber.” The mechanism of the reaction is discussed. |
