Abstract：
Photoinduced 3D printing via photocontrolled reversible-deactivation radical polymerization (photoRDRP) techniques has emerged as a robust technique for creating polymeric materials. However, methods for precisely adjusting the mechanical properties of these materials remain limited. In this study, we present a facile approach for adjusting the mechanical properties of 3D-printed objects by adjusting the polymer dispersity within a Norrish type I photoinitiated reversible addition-fragmentation chain transfer (NTI-RAFT) polymerization-based 3D printing process. We investigated the effects of varying the concentrations and molar ratios of trithiocarbonate (BTPA) and xanthate (EXEP) on the mechanical properties of the printed materials. Our findings demonstrate that increased concentrations of RAFT agents or higher proportions of the more active BTPA lead to a decrease in Young\'s modulus and glass transition temperatures, along with an increase in elongation at break, which can be attributed to the enhanced homogeneity of the polymer network. Using a commercial LCD printer, the NTI-RAFT-based 3D printing system effectively produced materials with tailored mechanical properties, highlighting its potential for practical applications.
摘要：
通过光控可逆失活自由基聚合(photoRDRP)技术的光诱导3D打印已经成为一种用于制造聚合物材料的强大技术。然而,精确调整这些材料的机械性能的方法仍然有限。在这项研究中,我们提出了一种简单的方法，通过在基于NorrishI型光引发可逆加成-断裂链转移（NTI-RAFT）聚合的3D打印过程中调节聚合物分散性来调节3D打印物体的机械性能。我们研究了改变三硫代碳酸酯（BTPA）和黄原酸酯（EXEP）的浓度和摩尔比对印刷材料机械性能的影响。我们的研究结果表明，增加RAFT剂的浓度或更高比例的更活性的BTPA导致杨氏模量和玻璃化转变温度的降低，随着断裂伸长率的增加，这可以归因于聚合物网络的均匀性增强。使用商用液晶打印机，基于NTI-RAFT的3D打印系统有效地生产了具有定制机械性能的材料，突出其实际应用的潜力。
