Nguyen Loc Tan, Du Prez Filip E
A Polymer Chemistry Research Group, Centre of Macromolecular Chemistry (CMaC), Department of Organic and Macromolecular Chemistry, Faculty of Sciences, Ghent University, Krijgslaan 281 S4, 9000 Ghent, Belgium.
Mater Horiz. 2024 Dec 9;11(24):6408-6415. doi: 10.1039/d4mh00823e.
Light-based processing of thermosets has gained increasing attention because of its broad application field including its use in digital light processing (DLP) 3D printing. This technique offers efficient design and fabrication of complex structures but typically results in non-recyclable thermoset-based products. To address this issue, we describe here a photocurable, dynamic β-amino ester (BAE) based cross-linker that is not only suitable for DLP printing but can also be chemically degraded transesterification upon the addition of 2-hydroxyethyl methacrylate (HEMA) as a decross-linker. This conceptually new protocol allows for efficient depolymerization with the direct restoration of curable monomers in a single step without the addition of external catalysts or solvents. By implementing this protocol, we have established a chemical recycling loop for multiple cycles of photo-cross-linking and restoration of cross-linkers, facilitating repeatable DLP 3D printing without generating any waste. The recycled materials exhibit full recovery of thermal properties and Young's modulus while maintaining 75% of their tensile strength for at least three cycles. Simultaneously, the presence of BAE moieties enables the (re)processability of these materials through compression molding.
基于光的热固性材料加工因其广泛的应用领域，包括在数字光处理（DLP）3D打印中的应用，而越来越受到关注。该技术提供了复杂结构的高效设计和制造，但通常会产生不可回收的热固性基产品。为了解决这个问题，我们在此描述一种基于光固化的动态β-氨基酯（BAE）交联剂，它不仅适用于DLP打印，而且在添加甲基丙烯酸2-羟乙酯（HEMA）作为解交联剂时，还可以通过酯交换进行化学降解。这个概念上全新的方案允许在不添加外部催化剂或溶剂的情况下，通过一步直接恢复可固化单体来实现高效解聚。通过实施这个方案，我们建立了一个化学循环回路，用于光交联和交联剂恢复的多个循环，促进了可重复的DLP 3D打印而不产生任何废物。回收材料在至少三个循环中，热性能和杨氏模量完全恢复，同时保持其拉伸强度的75%。同时，BAE部分的存在使这些材料能够通过压缩成型进行（再）加工。
