Developing biomass-modified hydrogel with high mechanical strength by a rosin-based crosslinking agent

Hydrogels are used in diverse applications owing to their superior water absorption and flexibility. At present, preparing hydrogels with high mechanical strength is becoming a hot topic. Hence, acrylpimaric acid-based acrylamide (APAAM) crosslinker were prepared from acrylpimaric acid, a derivative of natural rosin. The APAAM crosslinker synthesized a series of N, N-dimethylacrylamide/acrylamide (DMAA/AM) biomass-modified hydrogels with different crosslinking agent additions. The chemical structure, surface morphology, mechanical properties, rheological properties, and swelling properties of DMAA/AM hydrogels were investigated. The results showed that the tensile strength and compressive strength of hydrogels with APAAM (2.16 MPa, 874%) as a crosslinker are 15 times higher than the hydrogel with N, N'-methylene diacrylamide (BIS) (0.142 MPa, 254%) as crosslinker. This improvement benefit from the introduction of a rosin rigid ring. The swelling and thermal stability properties of hydrogels with APAAM as the crosslinker are also better than those of hydrogels prepared with BIS as the crosslinker. Besides, the mechanical strength and swelling properties of the hydrogels can be adjusted by the addition of an APAAM crosslinking agent. It was believed that this work provided a significant method for developing favorable mechanical properties for biomass-modified hydrogels.