Researchers develop reprocessable thermosets for sustainable 3D printing

(Nanowerk News) 3D printing of complex structures that contain submillimeter-sized features has eluded researchers for decades. Recent advancements in 3D printing have brought about viable 3D printing techniques such as digital light processing (DLP)-based systems that use ultra-violet (UV) light to transform initially-liquid polymer resins into free-standing solid structures in a precise, controlled manner.
Among all 3D printing materials, thermosetting photopolymers claim almost half of the market, and have been widely used in various fields due to their superior mechanical stability at high temperatures, excellent chemical resistance as well as good compatibility with high-resolution 3D printing technologies.
However, once these thermosetting photopolymers form 3D parts through UV curing triggered chemical reaction, the covalent networks are permanent and cannot be reprocessed, i.e., reshaped, repaired, or recycled. This unprocessable nature, combined with the explosion in 3D printing globally, is leading to vast waste of 3D printing materials with serious environmental implications
3D Printing Reprocessable Thermosets
3D printing reprocessable thermosets (3DPRTs) make 3D printed structures reshapeable, repairable and recyclable. (Image: Kavin Kowsari) (click on image to enlarge)
To address this environmental challenge, researchers from the Singapore University of Technology and Design (SUTD) have developed 3D printing 'reprocessable' thermosets (3DPRTs) that make 3D printed structures reshapeable, repairable and recyclable (Nature Communications, "Reprocessable thermosets for sustainable three-dimensional printing").
"We have developed, for the first time, the reprocessable thermosetting photopolymers designed for DLP based high-resolution 3D printing," said Assistant Professor Qi (Kevin) Ge from SUTD's Science and Math Cluster, who is one of the co-leaders of this project. He added: "Firstly, high-resolution structures can be reformed and fixed into arbitrary shapes subsequent to printing. This attribute improves printing efficiency as, for instance, 3D origami parts can be generated from flat, 2D layers. Secondly, the structure is repairable, meaning that damaged sites can be reprinted while perfectly maintaining structural integrity, prolonging product durability. Third and most importantly, our material can be recycled and reused for other applications."
"Overall, we believe the development of 3DPRTs provides a practical solution to address environmental challenges associated with the ongoing rapid increase in the consumption of 3D printing materials which are increasingly being utilized in a broad range of advanced applications including tissue engineering, soft robotics, nano-devices, and many others," said Professor Martin Dunn, the other co-leader of this project, and currently Dean of College of Engineering and Applied Science at the University of Colorado Denver.
Source: Singapore University of Technology and Design