The impact of thermal reprocessing of 3D printable polymers on their mechanical performance and airborne pollutant profiles

Abstract

The alterations in volatile organic compound (VOC) and ultrafine particulate (UFP) matter emission profiles following thermal reprocessing of multiple materials were examined. Additionally, mechanical performance of the materials was studied. The VOCs were identified by collecting air samples with Tenax® TA tubes and analyzing them with a GC–MS system. UFP concentrations were monitored with a portable ultrafine particle counter. Total VOC emissions of all materials were reduced by 28–68% after 5 thermal cycles (TCs). However, slight accumulation of 1,4-dioxane was observed with poly(lactic acid) materials. UFP emissions were reduced by 45–88% for 3D printing grade materials over 5 TCs but increased by 62% in the case of a waste plastic material over 3 TCs. The mechanical performance of the materials was investigated by measuring their tensile strengths (TSs) and elastic moduli (EM) with an axial-torsion testing system. The reprocessed materials expressed fluctuations in their 3D printing qualities and mechanical performances. The mechanical performances were observed to reduce only slightly after 5 TCs, and the trend was observable only after the data was mass-normalized. The TSs of the samples were reduced by 10–24%, while the EM were reduced by 1–9% after 5 TCs. The TS and EM of one material were increased by 14 and 33%, respectively. In conclusion, recycled polymers are plausible 3D printing feedstock alternatives as they possess acceptable mechanical performance and low emittance according to this study. Furthermore, non-3D printing grade polymers may be applied in a 3D printer with caution.

Investigation of bio-based and recycled printing materials for additive manufacturing

“…This significant deviation cannot be confirmed from other studies [23] and is probably due to incorrect 3D printing parameters. The measured tensile strength for rPLA deviate from the data sheet, but agree with the results of other studies [24]. The fractures also show the characteristic surfaces for the two printing materials.…”

Assessment of Occupational Exposures in the 3D Printing: Current Status and Future Prospects

“…Measurements are done using adsorbent tubes Tenax TA type to capture VOCs or SVOCs; tubes are connected with sampling devices with airflow from 50 to 200 ml/min. After sampling, tubes are analyzed using gas chromatography (GC) with flame ionizing detector (FID)/mass spectrometry (MS) detectors [44,65,66]. Thus, in 3D printing offices, total VOC concentration was found at high concentration in comparison with indoor air quality recommendations, in general.…”