The objective of this project was the synthesis of acrylate-siloxane elastomers with good thermal and solvent resistance. Of the many polymers investigated as gum rubber bases, vinyl triethoxy-silane-acrylonitrile, ethyl acrylate compositions were the best as measured by (1) swelling in 70-30 iso-octane-toluene and in Penola oil and (2) weight loss and flexibility after heating in air at 350 F. The addition of either dibutyl phosphite or polychlorotrifluoro ethylene powder (Kel F) to these gum rubbers generally maintained their flexibility in air at 350 F. for 250 to 1000 hours. As a reinforcing filler to provide good tensile strength. carbon black (Philblack O) was superior to other fillers tested. Trimene Base was effective as a vulcanization accelerator throughout this work. The vinyl triethoxysilane-ethyl acrylate gum rubbers could be vulcanized without additives through the formation of cross-linkages. Cross-linking probably took place through adjacent>SiOH groups formed in emulsion polymerization.

The objective of this project was the synthesis of acrylate-siloxane elastomers with good thermal and solvent resistance. Of the many polymers investigated as gum rubber bases, vinyl triethoxy-silane-acrylonitrile, ethyl acrylate compositions were the best as measured by (1) swelling in 70-30 iso-octane-toluene and in Penola oil and (2) weight loss and flexibility after heating in air at 350 F. The addition of either dibutyl phosphite or polychlorotrifluoro ethylene powder (Kel F) to these gum rubbers generally maintained their flexibility in air at 350 F. for 250 to 1000 hours. As a reinforcing filler to provide good tensile strength. carbon black (Philblack O) was superior to other fillers tested. Trimene Base was effective as a vulcanization accelerator throughout this work. The vinyl triethoxysilane-ethyl acrylate gum rubbers could be vulcanized without additives through the formation of cross-linkages. Cross-linking probably took place through adjacent>SiOH groups formed in emulsion polymerization.