Highly transparent radiation-resistant film materials based on cardo polymers

Cardo polyimides based on dianhydride of 3,3',4,4'-tetracarboxydiphenyloxide, and 9,9-bis-(4'-aminophenyl)fluorene and the corresponding polyterephthalamide have been studied. The films of cardo polymers exhibit high optical transmission at 500 nm (81 to 87%) and high thermal and radiation stability. After thermal treatment at temperatures up to 300°C and upon UV irradiation at a dose equivalent to 300 effective solar hours, the transmission decreased only by 1-3%. The strength properties of the films remained unchanged after consecutive UV and electron irradiation.