Used as a reactive polymer in coatings and adhesives due to its ability to form complexes with metals and acids. Acts as a precursor for quaternary ammonium salts in antimicrobial surfaces and ion-exchange materials. Employed in membrane technology for gas separation and as a support in catalysis, especially in palladium-catalyzed reactions. Also utilized in sensors and electronic materials for its pH-responsive behavior and ability to stabilize nanoparticles.