Recyclable Photopolymers for Sustainable 3D Printing

The use of photopolymers for 3D printing facilitates high-precision fabrication of geometrically complex structures, offering exceptional dimensional accuracy and rapid curing capabilities that position it as a cornerstone of modern additive manufacturing. However, conventional photopolymers form permanently crosslinked networks, which are resistant to recycling. This inherent limitation generates persistent waste streams that are fundamentally incompatible with circular economy principles. Consequently, the development of recyclable photopolymers that maintain printability while enabling closed-loop material recovery represents a critical Frontier for sustainable manufacturing. Advancing these materials will remain essential for reconciling technological progress with environmental stewardship in the foreseeable future. This review examines recent breakthroughs in recyclable photopolymer systems for 3D printing. First, mainstream photopolymerization techniques compatible with recyclable materials are outlined, followed by an elucidation of core design strategies incorporating chemical depolymerization, thermo-mechanical reprocessing, and noncovalent interactions. Fundamental recycling mechanisms are detailed alongside performance modulation methodologies. Furthermore, emerging applications in soft robotics, wearable devices, and bioelectronic devices where recyclable photopolymers enable multifunctional devices are highlighted. Finally, persistent challenges regarding network durability and recycling efficiency are addressed, and future research directions toward truly sustainable 3D printing are proposed.