Structural transformations of aromatic carborane-containing polyamides at elevated temperatures

There have been studied structural transformations which take place during ageing of various polyamides containing the m-carboran fragments within the temperature range of 100-350 deg C. The studies have been conducted in the saturated vapours of iodine and in pure oxygen. It has been shown that ageing of polyamides at relatively low temperatures is accompanied by cross-linking and breaking of macromolecules. The polyamides produced on the basis of 1.7-bis-(4-carboxyphenyl) carboran are characterized mainly by the branching and cross-linking processes, whereas the polyamides based on 1.7-carboran-dicarbonic acid are characterized mostly by the link breaking processes due to destruction of the carboran fragments. The different flow of the ageing process in the polyamides is associated with the different degree of mutual electronic influence of the carboran nucleus and amide group nitrogen