Tannic acid derived non-isocyanate polyurethane networks: Synthesis, curing kinetics, antioxidizing activity and cell viability

Bio-resourced non-isocyanate polyurethane (NIPU) network was synthesized to valorize a sustainable natural product (i.e., tannic acid, TA) toward biomaterials. Thus, a glycerol-based epichlorohydrin was glycidylated to form epoxidized TA (ETA). Facile chemical fixation of CO2 onto ETA was used to prepare carbonated TA (CTA) under normal conditions. Both aliphatic and aromatic amines were then used to convert CTA to NIPU networks. The networks were analyzed spectrally and thermally by FTIR, CP/MAS 13C NMR, and DSC, respectively. The amine-curing kinetics of CTA was evaluated based on Vyazovkin's advanced isoconversional method. The approach revealed different activation energies comparing to its epoxy counterpart, ETA. The TA-based NIPU possessed remarkable thermo-oxidation stability in comparison with its petroleum-based counterpart (OFF 2.38 vs. 0.12 min). The L929 fibroblast cells viability was used to evaluate the cytotoxicity and biocompatibility of the TA-based NIPU which proved its biocompatibility. Finally, the antioxidizing property of this polymer was ascertained by DPPH radical scavenging analysis. It was concluded that the value-added NIPU networks may be considered as good candidates for biomaterials.