Chemically Crosslinked Alginate Hydrogel with Polyaziridine: Effects on Physicochemical Properties and Promising Applications

Alginate biopolymer is widely employed in many industrialfields thanks to its pleasing features of biodegradability,biocompatibility, low toxicity, and relatively low cost. Thegelling process of alginate with divalent cations is fairly simpleand thus it is used as a versatile biomaterial to tailor the desiredmechanical and moisture properties. This study focused ondeveloping new gel formulations to enhance the properties ofcalcium-alginate hydrogel (CA). The newly synthesized hydro-gels, referred to as CA-CHEM gels, were chemically cross-linkedwith different ratios of pentaerythritol tris[3-(1-aziridinyl)propionate] (PTAP) through the reaction between thecarboxylic groups of alginate and aziridines of PTAP. Thereaction was successfully monitored by NMR. The new CA-CHEM gels were chemically characterized using FTIR-ATR, whileSEM analysis confirmed the changes in the porosity andhomogeneity of the network. Additionally, thermogravimetricanalyses and mechanical properties showed improvement indegradation stability and in structural strength, compared toplain CA, with an increasing PTAP content up to 1 % w/w.Finally, the new CA-CHEM gels effectively controlled waterabsorption and release. In particular, CA-CHEM-1 performed asthe most controlled system, making it promising for deliveringaqueous cleaning solutions on water-sensitive surfaces such asa wooden historical musical instrument.