In situ reaction of modified cellulose nanocrystals in shape memory polyacrylamide/gelatin composite hydrogel with enhanced performance

Abstract In this work, 3‐methacryloxypropyltrimethoxysilane modified cellulose nanocrystals (MCNCs) were first synthesized through a hydrolysis‐condensation reaction and subsequently incorporated with acrylamide and gelatin by an in situ reaction to fabricate shape memory polyacrylamide/gelatin composite hydrogels (PG‐MCNCs). It was found that the rigid MCNCs with methacryl and silanol or hydroxyl groups could act as chemical–physical crosslinking joints between polyacrylamide and gelatin and were capable of being well distributed in hydrogel. Meanwhile, the inserted MCNC filler could significantly improve the mechanical, shape memory and swelling resistance performances. Notably, the most effective improvement was obtained when 2 wt% MCNC was added to the hydrogel, i.e. the PG‐MCNC2 with suitable pore size and ordered pore size distribution showed superior tensile strength (0.50 MPa), elongation at break (2419%), compressive strength (0.15 MPa) and adhesion strength (19.8 kPa). Moreover, PG‐MCNC2 hydrogel exhibited better swelling resistance and thermally induced shape memory function (shape fixity ratio and shape recover ratio were 76.6% and 96.5%, respectively). Furthermore, the representative PG‐MCNC2 hydrogel possessed good cytocompatibility, which might be qualified for potential application as biomaterial. © 2023 Society of Industrial Chemistry.