Degradable 3D Printed Objects with Tunable Mechanical Properties via Photoinduced Free Radical Promoted Cationic RAFT Polymerization

The emergence and development of photopolymerization 3D printing based on controlled polymerization techniques have shown significant advantages in the fabrication of "living" polymeric materials with various functionalities. However, it is crucial to consider the degradation of these printed objects for environmentally friendly development. Herein, mono-, bi-, and trifunctional vinyl ether monomers with degradable ester cores were synthesized and used in 3D printing via photoinduced free radical promoted cationic reversible addition-fragmentation chain transfer polymerization. The model polymerization and printing conditions using these monomers were studied in detail. A fast printing speed (7.61-10.23 cm h(-1)) and tunable mechanical properties (tensile strength ranging from 1.7 to 41.6 MPa and Young's modulus ranging from 6.5 MPa to 1.3 GPa) can be achieved by adjusting the printing resins. Moreover, partial starting material (benzoic acids) could be easily recovered after degradation of the printed objects, offering a promising avenue for advancing the sustainable development of photopolymerization 3D printing based on controlled polymerization.