Carborane-containing polymers

Figure 66 The thermooxidatively stable silyl-carborane hybrid diethynylbenzene-silylene polymer 108 containing various carbon-carbon unsaturations. (Adapted from ref. 136.)...

A polycondensation reaction of 4,4 -dihydroxybiphenyl, sebacic, and m-carboranedicarboxylic acids was reported to produce a carborane-containing polymer (142) (Fig. 78) that led to the production of a new columnar phase at elevated temperatures.157 This new phase was formed in addition to the crystalline and liquid crystalline smectic phases typically formed from only 4,4 -dihydroxybiphenyl and sebacic acids. 

A molecular-size construction kit (159,160, and 161) (Fig. 85) for the assembly of carborane-containing grid-shaped polymers has been developed by Michl and co-workers.164 By synthesizing firmly connected, regular two-dimensional grid-shaped... 

Figure 86 The coordination-driven carborane-containing self-assembled polymers,...

Carborane-containing polymers may be conveniently divided into two broad classes (1) polymers incorporating carboranyl fragments within the pendent group attached to the main chain, and (2) polymers containing carboranyl fragments within their main chain. 

Carborane-containing polymers other than polysiloxanes are reported in the open literature and will be briefly mentioned here to give a flavor for the area. 

It is evident that efficient packing of polymer chains containing aromatic rings and carborane units requires significant longitudinal displacement of adjacent chains, unlike the situation for all-aromatic systems where little or no such displacement is observed.9... 

Recent studies concern the utilization of a polycarboranesiloxane for a thermally stable liquid phase in packed gas chromatographic columns identification of some polycarboranesiloxanes using pyrolysis gas chromatography , Dexsil 202 polymer pyrolysis and the structure and oxidative thermal stabilities of carborane-containing siloxanes . 

They are readily soluble in polar organic solvents such as diethyl ether, tetrahydrofuran, methylene chloride, and acetonitrile, but not in aliphatic hydrocarbons. It was found that (8) decomposed upon prolonged heating at 300 °C or during UV irradiation to form mercury, icosahedral carborane, and carborane-containing polymers. 

Principal Engineer, GE Silicones, Waterford, New York Carborane-containing polymers... 

Carborane-containing polymers Fullerene-containing polymers... 

---