Poly(N-isopropyacrylamide-co-maleic acid )/acylated chitosan thermosensitive hydrogels: preparation and properties

With the widespread use of hydrogels, injectable hydrogels for the human body require higher safety and non-toxicity. The most important is the choice of cross-linking agent to be green. In this study, acylated chitosan macromolecular crosslinkers (MCS) were prepared by maleic acid (MA) and chitosan (CS). Its structure was confirmed by FTIR and 1 H NMR and its degree of acylation was also determined. Then, a series of polymeric network hydrogels were investigated. The cross-linked copolymer poly( N -isopropyacrylamide-maleic acid copolymer)/acylated chitosan P(NIPAM- co -MA)/MCS is a series of thermosensitive hydrogels formed by free radical polymerization of NIPAM and MA with MCS as cross-linking agent. The apparent morphology, thermosensitive transition point, and hydrophilicity were investigated. The results show that the hydrogel has a homogeneous pore structure inside. The optimal low critical solution temperature (LCST) was 36.66 ℃. In addition, with the increase of maleic acid content, the water contact angle of the hydrogel is smaller, that is, the hydrophilic effect is better. The results indicate that the P(NIPAM- co -MA)/MCS hydrogels were synthesized successfully and may be a potential material for biomedical, drug delivery, or absorption application. This study can provide a certain research basis and relevant theoretical basis for clinical practice. Graphical abstract