POLYETHERKETONES FROM DIARYLCARBORANES - A NEW APPROACH TO SEMI-INORGANIC POLYMERS

Linear polyetherketones containing both aromatic rings and icosahedral carborane (C2B10) cages in the main chain have been synthesized by su peracid-promoted polycondensation between bis(4-phenoxyphenyl derivati ves of ortho- or meta-carborane and aromatic or aliphatic dicarboxylic acids. Under strictly anhydrous conditions, polymers of high molecula r weight (M-w > 150 000) are readily obtained. These new materials are amorphous and readily soluble in organic solvents, to give solutions from which strong, transparent films may be cast. Poly(aryletherketone carborane)s are characterized by very high mass-retention (up to 93%) on thermolysis under nitrogen to 850 degrees C, and demonstrate extrem e resistance to combustion, losing as little as 3% of their mass on py rolyis at 850 degrees C in air. A new type of ionomer, based on the [- C2B9H10-](-) sub-unit, is obtained by deboronation of poly(aryletherke tone-ortho-carborane)s under strongly basic conditions. (C) 1997 Elsev ier Science Ltd.