D2-m-carborane siloxanes. V. Structure–property relationships

D₂-m-decacarborane dimethylsiloxane has unusual thermal stability and resistance towards reversion, however, this material exhibits a crystalline phase, T_m at 68°C. To obtain an elastomeric material, this crystallinity is disrupted by replacing 30 to 50% of the m-carborane with p-carborane moieties or by the incorporation of phenyl moieties on the polymer backbone. The latter approach is preferred since improved thermo-oxidative stability accompanies this modification. Correlation of the glass transition temperature and thermo-oxidative stability with the polymer structure are presented.