Effect of pressure and temperature on interfacial tension of poly lactic acid melt in supercritical carbon dioxide

© 2015. This manuscript version of Effect of Pressure and Temperature on Interfacial Tension of Poly lactic acid melt in supercritical carbon dioxide is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the accepted manuscript version of a published article. Published by Elsevier in the journal "Thermochimica Acta" volume 609, http://dx.doi.org/10.1016/j.tca.2015.04.005 The interfacial tension of poly lactic acid (PLA) melt is measured in supercritical carbon dioxide (CO2) at the temperature range of 143 °C to 168 °C and CO2 pressures up to 2000 psi, using Axisymmetric Drop Shape Analysis Profile (ADSA-P). The results show a decrease in interfacial tension with increasing temperature and pressure. However, the interfacial tension dependency on temperature at high pressures decreases because of a reduction in CO2 solubility at high temperatures. The relationship between the interfacial tension and the density-difference of polymer-supercritical CO2 mixtures is also examined by the generalized Macleod equation. Moreover, the range of stability for the melted drop, in interfacial tension measurements, is obtained by dimensionless Bond number. The results indicate the validity of the measurements for Bond number between 0.36 and 0.48. Natural Sciences and Engineering Research Council (NSERC) Network for Innovative Plastic Materials and Manufacturing Processes (NIPMMP) Canada Research Chairs (CRC)