Gas Uptake of 3-D Printed Acrylonitrile Butadiene Styrene (ABS) Using a Vacuum Apparatus Designed for Absorption and Desorption Studies
Makfir Sefa, Zeeshan Ahmed, James A. Fedchak, Nikolai N. Klimov, Julia K. Scherschligt
We describe a vacuum apparatus for determining the outgassing rate into vacuum, the diffusion coefficient, and the amount of gas absorbed for various materials. The diffusion coefficient is determined from a model applied to time-dependent desorption data taken using a throughput method. We used this method to determine the diffusion coefficient, D, for H2O in 3-D printed acrylonitrile butadiene styrene (ABS). We found DH2O = 8.3 × 10-8 cm2/s ± 1.3 × 10-8 cm2/s (k = 1; 67% confidence interval) at 23.2 °C. We checked this result by comparing to the diffusion coefficient we determined another way: a gravimetric method in which the sample weight is monitored as it absorbs gas from the atmosphere. The two methods compared to within 3%, which is well within the uncertainty of the measurement. We also found that ABS preferentially absorbs water when exposed to atmospheric gas. Indeed at least 80% of the gas absorbed by the ABS from the atmosphere is water. The total amount of all atmospheric gas absorbed by ABS is about 0.35% by weight when exposed to ambient air in the laboratory, which was at a pressure of 101 kPa with a relative humidity of 57% at 22.2 °C.