Singapore Centre for 3D Printing, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore; School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Singapore Centre for 3D Printing, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore; School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Sci Total Environ. 2019 Nov 20;692:984-994. doi: 10.1016/j.scitotenv.2019.07.257. Epub 2019 Jul 17.
Ultrafine particles (UFP) and volatile organic compounds (VOC) emitted from fused deposition modelling (FDM) 3D printing have received widespread attention. Here, we characterize the formation mechanisms of emissions from polymer filaments commonly used in FDM 3D printing. The temporal relationship between the amount and species of total VOC (TVOC) at any desired operating thermal condition is obtained through a combination of evolved gas analysis (EGA) and thermogravimetric analysis (TGA) to capture physicochemical reactions, in which the furnace of EGA or TGA closely resembles the heating process of the nozzle in the FDM 3D printer. It is generally observed that emissions initiate at the start of the glass transition process and peak during liquefaction for filaments. Initial increment in emissions during liquefaction and the relatively constant decomposition of products in the liquid phase are two main TVOC formation mechanisms. More importantly, low heating rate has the potential to restrain the formation of carcinogenic monomer, styrene, from ABS. A TVOC measurement method based on weight loss is further proposed and found that TVOC mass yield was 0.03%, 0.21% and 2.14% for PLA, ABS, and PVA, respectively, at 220 °C. Among TVOC, UFP mass accounts for 1% to 5% of TVOC mass depending on the type of filaments used. Also, for the first time, emission of UFP from the nozzle is directly observed through laser imaging.
熔融沉积建模（FDM）3D 打印产生的超细颗粒（UFP）和挥发性有机化合物（VOC）受到广泛关注。在这里，我们对 FDM 3D 打印中常用的聚合物细丝排放物的形成机制进行了研究。通过结合气相色谱分析（EGA）和热重分析（TGA），可以获得在任何所需操作热条件下总 VOC（TVOC）量和种类的时间关系，从而捕捉物理化学反应，其中 EGA 或 TGA 的炉体与 FDM 3D 打印机中喷嘴的加热过程非常相似。一般来说，排放物在玻璃化转变过程开始时就会产生，并在细丝液化过程中达到峰值。在液化过程中排放物的初始增量和液相中产物的相对恒定分解是两种主要的 TVOC 形成机制。更重要的是，较低的加热速率有可能抑制致癌单体苯乙烯从 ABS 中的形成。进一步提出了一种基于重量损失的 TVOC 测量方法，发现 PLA、ABS 和 PVA 在 220°C 时的 TVOC 质量产率分别为 0.03%、0.21%和 2.14%。在 TVOC 中，UFP 质量占 TVOC 质量的 1%至 5%，具体取决于所用细丝的类型。此外，首次通过激光成像直接观察到从喷嘴排放的 UFP。
