Highly Stable Polymers based on Poly(m -carboranyl-siloxane) Elastomers

Abstract

Poly(m-carboranyl-siloxane) elastomers containing a mixture of di-methyl-and methyl(phenyl)-silyl units were synthesised using the Ferric Chloride catalysed condensation reaction between di-chloro-di-organosilane and 1,7-bis(di-methyl(methoxy)silyl)-m-carborane. These prepared polymers were aged either by heating in air at elevated temperature or by γirradiation from a 60 Co source. Multinuclear ( 1 H, 13 C and 11 B) solid and solution state nuclear magnetic resonance was used to evaluate degradation. γ-irradiation doses to 1 MGy were found to induce only a small reduction in elastomer properties as evidenced by a reduction in segmental chain dynamics. Ageing at temperatures below 350 o C similarly displayed a small reduction in segmental chain dynamics together and a concomitant weight loss as measured by differential scanning calorimetry. Above 350 o C degradation of the elastomer was dramatic with a decreased segmental chain dynamics and oxidation of the carborane cage, vide infra.

Greatly enhanced thermo‐oxidative stability of polybenzoxazine thermoset by incorporation of m‐carborane

“…The thermo‐oxidative stability of the polymers could be greatly improved by chemical incorporation of icosahedral caboranes. Carborane‐containing polymers, such as polyetherketones, polysilanes and polysiloxanes have been prepared as advanced materials with unique thermostabilities . However, to the best of our knowledge, no study of polybenzoxazines based on icosahedral caboranes has been reported.…”