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VOC Emissions Influenced by Polymer Additives in 3D Printing
Citation:
Al-Abed, Souhail R., Phillip M. Potter, F. Hassan, AND S. Lominicki. VOC Emissions Influenced by Polymer Additives in 3D Printing. Global Summit on Regulatory Science, Stresa, N/A, ITALY, September 24 - 27, 2019.
Impact/Purpose:
3D printing using fused deposition model (FDM) has become more affordable and became common in workplaces and households increasing the interest over the hazardous volatile organic compounds (VOCs) emissions generated when the filaments are heated. We demonstrated that carbon nanotubes and metal particles present in the filaments as additives influence the generated VOC emissions. We also found that unadvertised structural additives and unreacted polymerization compounds may increase the amounts of emissions or increase the toxicity of the emissions. The user is likely unaware of such risk associated with unadvertised compounds. It is crucial to communicate these findings on an international stage at the Global Summit on Regulatory Science 2019 Nanotechnology and Nanoplastics. This will allow the international community to discuss our findings in a global context. We will also exchange ideas with colleagues on how we have developed the methods to measure and characterize the VOCs from the 3D printers. This is a great opportunity for the EPA to be seen as an important contributor to the innovation in environmental science at a global scale.
Description:
The increase in number of 3D printers found in households and workplaces has led to a growing concern over their hazardous emissions. One category of emissions from fused deposition modelling (FDM) printers consists of volatile organic compounds (VOCs). While VOC emissions from common pristine polymers have been investigated, these studies tend to focus on thermal degradation products that result directly from the polymer backbone. Many 3D printer filaments contain unreacted polymerization initiators or utilize additives to achieve various aesthetic and structural properties that may influence VOC emissions. Three filaments were selected based on the presence of a VOC influencing reactant or additive. A commercially-available, 3D printer nanocomposite filament of carbon nanotubes (CNTs) and acrylonitrile-butadiene-styrene (ABS) was analyzed with respect to its VOC emissions during simulated FDM and compared with an ABS filament without CNTs. In addition, a polylactic acid (PLA) filament with added siloxanes and a polycarbonate (PC) filament with unreacted phosgene were also studied. VOC emissions were quantified and characterized under a variety of conditions to simulate the thermal degradation that takes place during FDM. In the ABS-CNT filament, increasing residence time and temperature resulted in significant increases in VOC emissions and oxygen content of the reaction gas influenced the VOC profile. The presence of CNTs in the filament influenced VOC yields and product ratios and suggests a reaction mechanism involving an adsorbed styrene species. The PLA filament emitted six siloxane compounds under standard printing conditions, with some in higher concentration than any other common PLA VOC emission. The presence of unreacted phosgene in the PC filament led to the formation of chlorinated VOCs, most alarmingly, chlorobenzene. The present study has identified an increased potential to risk associated ssociated with common additives used in 3D printing.