Digital Light Processing 3D Printing of Enhanced Polymers via Interlayer Welding

Digital light processing (DLP) 3D printing is advantageous in high printing efficiency and printing resolution for fabricating complex structures across various applications. However, the layer-by-layer curing manner of DLP leads to weak interlayer adhesion and the anisotropic mechanical properties of printed objects. Here, linear polymers are introduced into commercial resins to weld the interlayer by the diffusion and entanglement of linear polymers after DLP printing via heat treatment. This introduction of linear polymers not only shows a strengthening and toughening effect on the printed objects, but also has no negative impact on the DLP printability. The tensile strengths of objects containing 4.7 wt% polycaprolactone can reach up to ≈500% of that of neat samples in any printing direction. This simple strategy by adding linear polymers into printing resins provides an effective access to prepare DLP printed objects with improved mechanical properties as well as ensure printing resolution and printing efficiency.