Submitted to: Chemical Society Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 5, 2001
Publication Date: N/A
Technical Abstract: The surface energy parameters of polymers can be determined from its interfacial tensions with at least two other polymers whose surface energy parameters are known. This method has been used rarely in the past mainly due to difficulties with direct measurement of the interfacial tension of high molecular weight and high viscosity polymer blends using current equilibrium methods such as sessile or pendant drop. This problem can be overcome by using the imbedded-fiber retraction (IFR) method, which is a dynamic method particularly suitable for direct measurement of the interfacial tensions of high viscosity polymer blends in a relatively short period of time. In this work, the IFR was used to directly measure, for the first time, the interfacial tension of blends of polycaprolactone (PCL) with polymethylmethacrylate (PMMA) and polystyrene (PS). The interfacial tensions were measured at 160 and 180 deg C. The measured interfacial tensions along with the known surface energy parameters of PMMA and PS were used to estimate the gamma**D and gamma**P of PCL. We obtained a gamma**P value of 10.9 dyn/cm, that was independent of temperature but also on the high end of the 2.1-10.3 dyn/cm range reported for PCL using wettability methods. Our gamma**D values were 49.5 and 42.8 dyn/cm at 160 and 180 deg C, respectively, which are outside the 24.4-41.9 dyn/cm range reported for PCL using wettability methods at room temperature.