Highly Heat-Resistant Protective Coatings of Silica Optical Fibers: from Functionalization of Polyimides to Photopolymerizable Compositions

New approaches to the formation of primary protective coatings for silica optical fibers based on polyimides or their photocurable compositions with diacrylates are presented. Particular attention is paid to improving the adhesion of the polymers to the fiber by introducing carboxyl groups or amide bonds into the polyimide. The advantages of high-temperature self-catalyzed synthesis of carboxylated polyimides and the use of photocurable compositions to improve the manufacturability and properties are shown.