Photoinduced 3D Printing through a Combination of Cationic and Radical RAFT Polymerization

Abstract

Photopolymerization-based three-dimensional (3D) printing techniques have been widely utilized to fabricate polymeric materials with complex architectures. The application of reversible deactivation radical polymerization (RDRP) in 3D printing is emerging as a powerful tool to introduce various postprinting abilities but is still at an early stage. Here, a photoinduced free radical-promoted cationic reversible addition–fragmentation chain transfer (RAFT) polymerization method was developed, utilizing the direct photolysis of the RAFT agent as a radical source, which was further combined with photo-iniferter RAFT polymerization to prepare polymer networks. The polymerization mechanism was studied by model polymerization using monofunctional monomers. The effects of each component on the properties of the final materials and polymerization behavior of the cross-linking systems were studied in detail. This method was successfully applied in a digital light processing (DLP) technique-based commercial 3D printer. Finally, polymer welding of the printed objects through both cationic and radical RAFT chain extension was realized, expanding avenues of postprinting and future applications in various fields.