A new method for the simultaneous determination of surface tension and density of polymer melts

Abstract

By employing a new strategy presented recently by Wulf etal., axisymmetric drop shape analysis (ADSA) can be used to determine simultaneously the surface tension and the density of polymer melts from sessile drops at elevated temperatures. This required the modification of the ADSA algorithm to replace the density by the mass of the drop as input parameter and the development of a closed high temperature chamber whose temperature can be precisely controlled. In addition, special sample holders for the formation of pendant and sessile drops at elevated temperatures were needed. Recently, their design has been improved, which is described in this paper. For a commercial epoxy resin (DER 664 UE), it is shown that measurements with sessile drops yield essentially the same surface tension values and temperature coefficients as with pendant drops. The densities determined with ADSA are comparable to independent PVT results.