ИСТИНА

Carboxylated polyimides (CxPIs) have great potential for the development of gas separation membranes, high-temperature resistant coatings, ion-conducting materials, aerogels, nanocomposites, etc. However, the synthesis of CxPIs has traditionally involved a long and expensive two-step process through the formation of unstable poly(amic acid) followed by thermal or chemical imidization. A new strategy has been developed, which consists in a one-step high-temperature synthesis of CPIs based on 3,5-diaminobenzoic acid (DABA), whose carboxyl groups provide the autocatalytic effect. The efficient synthesis of a wide variety of CxPIs without an additional catalyst allows to use the obtained solutions in situ in the production of various functional materials. In particular, varnishes based on CxPIs form a primary protective coating of silica optical fiber that are characterized by superior performance compared to their commercial counterpart in terms of manufacturing technology, thermal and hydrolytic stability.