Tuning the Mechanical Properties of 3D-printed Objects by the RAFT Process: From Chain-Growth to Step-Growth

Angew Chem Int Ed Engl. 2024 Mar 4;63(10):e202318564. doi: 10.1002/anie.202318564. Epub 2024 Jan 26.

Abstract

Photoinduced 3D printing based on the reversible addition-fragmentation chain transfer (RAFT) process has emerged as a robust method for creating diverse functional materials. However, achieving precise control over the mechanical properties of these printed objects remains a critical challenge for practical application. Here, we demonstrated a RAFT step-growth polymerization of a bifunctional xanthate and bifunctional vinyl acetate. Additionally, we demonstrated photoinduced 3D printing through RAFT step-growth polymerization with a tetrafunctional xanthate and a bifunctional vinyl acetate. By adjusting the molar ratio of the components in the printing resins, we finely tuned the polymerization mechanism from step-growth to chain-growth. This adjustment resulted in a remarkable range of tunable Young's moduli, ranging from 7.6 MPa to 997.1 MPa. Moreover, post-functionalization and polymer welding of the printed objects with varying mechanical properties opens up a promising way to produce tailor-made materials with specific and tunable properties.

Keywords: 3D printing; RAFT polymerization; mechanical properties; step-growth polymerization.