NH3‐modified swelling of silica‐filled silicone rubber

摘要

AbstractThe NH3‐modified swelling method was used for fume silica‐filled silicone rubber compounds and vulcanizates. The method provides an estimation of the polymer–filler interaction in the system. Bound rubber reduction due to the modified swelling is shown to be dependent on the silica surface silanol content in the compound. The swelling behavior of silica‐filled vulcanizates was also studied in an NH3atmosphere. The fraction of polymer–filler attachments in the vulcanizates was found not to depend on the particle size of silica and its surface modification, depending only on the total polymer–filler contact area in the system. No relation was found between bound rubber content in a compound and swelling of a filled vulcanizate of the same composition. The strong rubber‐to‐filler adherence found in toluene changed to nonadherence under NH3‐modified swelling conditions. The NH3‐induced cleavage of silica–silicone rubber attachments was found to be nearly completely reversible. In the silica‐filled silicone rubber vulcanizates, the fraction of polymer–filler attachments due to polymer–filler interaction represents a substantial contribution to the tot