Preparation, characterization and swelling behaviors of polyurethane-grafted calcium alginate hydrogels

• Mono-capped polyurethane monomer with a vinyl group was synthesized.
• Self-crystallizing calcium alginate-based polyurethane was synthesized.
• Give full play to the advantages of polyurethane.
• Self-crystallizing structure avoids the loss of crystal grain.
• It׳s thermal stability and swelling degree were enhanced.

Polyurethane was synthesized by the reaction of isophorone diisocyanate, 2-hydroxyethyl methacrylate and diethylene glycol. Then polyurethane grafted calcium alginate gel material was prepared via free-radical grafting polymerization with azobisisobutyronitrile as an initiator. Modified calcium alginate hydrogel was improved in thermal property, crystallinity and anti-swelling properties. The reason is that polyurethane side chains affect the arrangement of calcium alginate by forming highly ordered crystal region.