Interfacial Tension Of Polymer Melts Under Supercritical Carbon Dioxide

In this work, an apparatus was constructed for measuring the interfacial tension of polymer melt using pendant drop method under high temperature and gas pressure. Through in-situ recording the shape profile of a polymer melt drop in a high pressure and temperature view cell, the interfacial tension of polypropylene (PP) at the temperatures ranging from 180 to 220℃and CO2 pressure from 0 to 15 MPa, and polyethersulfone (PES) at the temperatures ranging from 290 to 310℃and CO2 pressures from 0 to 17 MPa was determined by using the pendant drop method. The Tait equation and Sanchez-Lacombe (S-L) equation of state were used to determine the density of pure polymer melt and polymer/C02 solution, respectively. The results showed that the interfacial tension of polymer decreased almost linearly with increasing CO2 pressure at lower CO2 pressures, and tended to level off at higher CO2 pressures at a given temperature, and it decreased with increasing temperature at a given CO2 pressure. Moreover, combined with the solubility of CO2 in polymers, a model was constructed to correlate the experimentally measured interfacial tension of PP and PES.