Synthesis and properties of poly(m‐carborane‐siloxane) elastomers

Abstract

Organic boron polymers are of interest to AWE, and a significant improvement would be to make components from a single phase material that enables the boron content to be maximised and the elastomeric properties to be tuned to requirement. This paper is a summary of the work carried out towards the synthesis and characterisation of poly(m‐carborane‐siloxane) rubbers. These rubbers have been synthesised by the Ferric Chloride‐catalysed condensation reaction between dimethoxy‐m‐carborane terminated monomer and dichlorodimethylsilane. Phenyl modified and Phenyl‐vinyl modified variations have been synthesised in addition to the unmodified poly(m‐carborane‐siloxane) polymers. The unmodified poly(m‐carborane‐siloxane) shows some crystallinity but the modified versions are amorphous and have good elastomeric properties. Overall, the measured boron content is in close agreement to that expected from the repeat unit, suggesting the synthesised rubbers have been successfully prepared. It is also demonstrated that the carborane unit offers increased thermal stability and retention of ‘rubber‐like’ properties even after ageing at high temperature.

On the scintillation efficiency of carborane-loaded liquid scintillators for thermal neutron detection

“…In addition, the sample density in each group is considered to be constant because the mole fraction of carborane in all samples is r0. 13.…”

“…The delocalized 3-dimensional bonding in the icosahedral geometry provides strong thermal, kinetic, and photochemical stability. A family of polymers with remarkable heat-resistance was synthesized with carboranes, taking advantage of their thermal stability [13]. Biomedical investigations made use of the hydrophobicities to link carborane motifs to biomolecules for 10 B neutron-capture therapy [14].…”

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

“…The fabrication of shaped components from the synthesised polymers has been reported previously publication [11]. 1,7-bis(di-methyl-silyl)-mcarborane precursor (18g, 56.23 mmol); di-chloro-dimethylsilane (6.12g, 47.44 mmol); dichloro-methyl(phenyl)silane (1.60g, 8.38 mmol) and Ferric Chloride (0.1g, 0.61 mmol) were mixed together in a three neck reaction vessel (500 ml).…”

Carborane–Siloxanes: Synthesis and Properties. New Possibilities for Structure Control

“…A drawback of the method is side gelation that hampers the formation of high-molecular linear polymers [41,42]. In the case of polycondensation, this problem was solved by the use of phenyl-substituted dimethoxy-m-carboranes, which gave rise to elastomers featuring molecular masses of about 150 kDa [43]. The thermal properties of the polymers with arylene carborane moieties were reviewed by Vinogradova et al [44].…”