Preparation of bifunctional macronet polymers having both strongly and weakly acidic groups in one step. Gel—solution transition of a transformable hydrogel

• Published in: Polymer (Guilford) 1996, Vol.37 (5), p.855-861
• Main Authors: Theodoropoulos, Athanasios G., Theodosakis, George I., Valkanas, George N., Mamalis, Athanasios D.
• Format: Article
• Language: English
• Subjects: Applied sciences; bifunctional ion exchangers; Chemical modifications; Chemical reactions and properties; Exact sciences and technology; gel—solution transition; macronets; Organic polymers; Physicochemistry of polymers; post-polymerization crosslinking; swelling; transformable hydrogel
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/0032-3861(96)87265-X

The hydrolysis, sulfonation and crosslinking modification of a poly(styrene- co-acrylonitrile) copolymer in one step was studied. An extremely vigorous process has been developed for the preparation of a series of hydrophilic gels bearing strongly and weakly acidic groups on the same polymer backbone. The products were characterized using infra-red spectra, scanning electron microscopy, elemental analysis and titrimetric determination of the strongly and weakly acidic groups. Kinetic data and swelling measurements in aqueous media were also performed. A fully transformable hydrogel was obtained from a series of macronet products having different degrees of crosslinking. This irreversible gel—solution transition was recorded within 15 weeks, a fact that indicates that these polymers may have specific applications in fields where separation media are required, or as transformable soil conditioners.