Developing recyclable biobased photopolymers for UV-curable 3D printing is of great significance for sustainable development of 3D printing industry. In this work, novel recyclable and reprintable castor oil (CO)-based photopolymers for digital light processing (DLP) 3D printing were developed via hindered urea bonds, a type of dissociating dynamic covalent bonds. Remarkably, the printed objects could be recycled in 4 h at 90 °C or 2 h at 100 °C without any catalysts or solvents, and the recycled resins had similar physiochemical properties, polymerization kinetics, and printing resolutions as the original resin. Furthermore, reprintable sacrificial molds and thermochromic materials were achieved with the optimal biobased resin, which can be used in complicated model casting and information encryption/anti-counterfeiting areas. In particular, thermochromic microcapsules could be recycled nondestructively from the printed thermochromic materials and reused in DLP 3D printing.

开发用于紫外光固化3D打印的可回收生物基光聚合物对3D打印产业的可持续发展具有重要意义。在这项工作中，开发了用于数字光处理 (DLP) 3D 打印的新型可回收和可再打印蓖麻油 (CO) 基光聚合物。受阻脲键，一种解离的动态共价键。值得注意的是，在没有任何催化剂或溶剂的情况下，打印的物体可以在 90°C 4 小时或 100°C 2 小时内回收，并且回收的树脂具有与原始树脂相似的物理化学性质、聚合动力学和打印分辨率。此外，通过优化的生物基树脂，实现了可重复打印的牺牲模具和热致变色材料，可用于复杂的模型铸造和信息加密/防伪领域。特别是，热致变色微胶囊可以从打印的热致变色材料中无损回收，并在 DLP 3D 打印中重复使用。