Sustainable Materials for Additive Manufacturing

Additive manufacturing has revolutionized polymer material engineering, yet it remains heavily reliant on petroleum-based polymers and non-recyclable thermosets, particularly in vat-photopolymerization. This review evaluates the ongoing transition toward sustainable 3D printing and identifies a critical “functionalization paradox”: the chemical modifications required to make bio-derived feedstocks printable often increase their carbon footprint and compromise their inherent biodegradability. Herein, we categorize sustainable materials through a two-pronged circularity roadmap. First, after reviewing bio-based functionalized monomers, we review inherently reactive bio-monomers, such as lipoic acid derivatives, which bypass synthetic modification to enable rapid polymerization and closed-loop chemical depolymerization. Second, we review covalent adaptable networks (CANs) as a potential solution for thermosets that require synthetic functionalization, providing a pathway to reprocessability. Finally, we conclude that achieving truly circular 3D printing requires a fundamental shift in design philosophy: moving from the functionalization of biomass to the exploration of natural molecular architecture and dynamic network topologies.