Itaconic acid/cellulose-based hydrogels with fire-resistant and anti-freezing properties via vat photopolymerization 3D printing

Hydrogel-born materials have garnered significant interest due to their inherent flame retardant properties and eco-friendly characteristics. In light of the diminishing petroleum reserves and the escalating environmental challenges, there is an urgent impetus to exploit high-value applications of naturally occurring resources and to advance research in sustainable manufacturing technologies. In this vein, we describe an innovative and sustainable methodology for the development and production of flame-retardant hydrogels. This approach perfectly integrates renewable itaconic acid and cellulose derivatives with rapid vat photopolymerization (VP) 3D printing technology, which affords a green and efficient route for materials processing. Specifically, the biomass-based ink formulated for 3D printing demonstrates excellent visible-light curing properties, achieving a maximum doublebond conversion of 45.3 % within 10 min of exposure to visible-light LED under ambient conditions. Moreover, the resultant 3D-printed biomass-based hydrogels exhibit commendable flame-retardant performance, as evidenced by a V-0 flammability rating and a Limiting Oxygen Index (LOI) value of 60.2 %. They also possess desirable mechanical attributes (95.2 kPa) and exceptional thermal stability, enduring high temperatures for up to 12 min. Notably, these hydrogels exhibit remarkable freeze tolerance, maintaining their functionality even at profoundly low temperatures. This study demonstrates a novel strategy for the design and production of flameretardant materials, contributing to the pursuit of green sustainability.