Ko Jong Wan
3D Printing Manufacturing Process Center, Smart Forming Process Group, Korea Institute of Industrial Technology (KITECH), Ulsan 44776, Republic of Korea.
Polymers (Basel). 2024 Jan 29;16(3):370. doi: 10.3390/polym16030370.
Digital light processing (DLP) has the advantages of higher printing speed and product precision than other 3D printing technologies. However, DLP products have low mechanical strength owing to the inherent properties of photocurable materials. Graphitic carbon nitride (GCN), which is an abundant hydrogen bonding motif (-NH, -NH), has low solubility in most solvents; thus, to use GCN as a reinforcement of the polymer matrix, optimal dispersion processes must be applied. In this study, GCN was proposed as a novel reinforcing material to improve the mechanical properties of photocurable epoxy acrylate (EA) resins for DLP. Herein, two-step (planetary mixing and ultrasonication) processes were applied to disperse GCN within EA, and the dispersion performance was identified by checking the degree of precipitation over time. To test the printability of the dispersed GCN/EA composites subjected to DLP 3D printing, cube specimens of GCN/EA composites were prepared, and the dispersed GCN/EA output had a low dimensional error of 0.3-1.3%, while the undispersed composite output showed larger dimensional errors of 27.7-36.2%. Additionally, in the mechanical test of the DLP-3D-printed sample (dispersed GCN/EA composite), the tensile strength and elastic modulus of the dispersed GCN/EA composite specimen were measured to be 75.56 MPa and 3396 MPa, respectively, which were improved by 22% (tensile strength) and 34% (modulus of elasticity) in relation to those of the neat EA specimen. This study is the first to use GCN as a reinforcement and manufacture a composite product for DLP with excellent performance (22% increased tensile strength) through the optimal dispersion of GCN. Considering the high mechanical performance, DLP products using the GCN/EA composites can be used in industries such as automobiles, shipbuilding, and aviation.
数字光处理（DLP）技术相较于其他3D打印技术，具有更高的打印速度和产品精度。然而，由于光固化材料的固有特性，DLP产品的机械强度较低。石墨相氮化碳（GCN）含有丰富的氢键基序（-NH，-NH），在大多数溶剂中的溶解度较低；因此，要将GCN用作聚合物基体的增强材料，必须采用最佳的分散工艺。在本研究中，提出将GCN作为一种新型增强材料，以改善用于DLP的光固化环氧丙烯酸酯（EA）树脂的机械性能。在此，采用两步法（行星式混合和超声处理）将GCN分散在EA中，并通过检查随时间的沉淀程度来确定分散性能。为了测试经过DLP 3D打印的分散GCN/EA复合材料的可打印性，制备了GCN/EA复合材料的立方体试样，分散GCN/EA的输出具有0.3 - 1.3%的低尺寸误差，而未分散的复合材料输出显示出27.7 - 36.2%的较大尺寸误差。此外，在DLP 3D打印样品（分散GCN/EA复合材料）的力学测试中，分散GCN/EA复合材料试样的拉伸强度和弹性模量分别测量为75.56 MPa和3396 MPa，相对于纯EA试样，拉伸强度提高了22%，弹性模量提高了34%。本研究首次将GCN用作增强材料，并通过GCN的最佳分散制造出具有优异性能（拉伸强度提高22%）的DLP复合产品。考虑到其高机械性能，使用GCN/EA复合材料的DLP产品可应用于汽车、造船和航空等行业。
