Recyclable thermosetting polymers for digital light processing 3D printing

Abstract

3D printing of various polymers has attracted great attention and developed rapidly in recent years. Digital light processing (DLP) has recently emerged as a fast growing 3D printing technique due to its high resolution and high speed. However, the lack of printable high-performance materials limits its broad applications. In addition, with the increasing adoption of DLP 3D printing, the efficient recycling of printed thermosetting materials is highly desired. Herein, we proposed a two-stage curing approach involving dynamic reactions by using the acrylate-epoxy hybrid resin for the recyclable DLP 3D printing of high-performance thermosetting polymers. Bond exchange reactions (BERs) could establish covalent bonds between the acrylate network and the epoxy network, thus partially triggering the copolymerization. The resulting new polymers exhibited excellent mechanical properties. A small-molecule assisted BER method was then used to efficiently depolymerize the thermosetting printed parts into soluble oligomers, which were formulated with fresh photopolymers for the next round of printing. The reprinted samples still showed good mechanical properties comparable to the virgin ones. In addition, the new polymers demonstrated potential applications in 4D printing of smart actuators. This work opens a novel avenue for green manufacturing technologies.

Keywords

• 3D printing
• Recycle
• Reprint
• Bond exchange reactions (BERs)