COMPARATIVE MEASUREMENTS OF INTERFACIAL-TENSION IN A MODEL POLYMER BLEND

This work shows the application of several experimental methods to the measurement of the interfacial tension, sigma, between two immiscible polymers. a quantitative knowledge of the interfacial tension is impo rtant in view of the crucial role that this parameter plays in polymer blend processing. Common to all methods presented here are two main p oints. The first is that a is obtained from experiments where the shap e of the interface between the liquids is directly observed by means o f optical microscopy techniques. The second point is that the interfac e geometry is controlled by a balance between the interfacial force an d the viscous stresses generated by some flow applied to the system. M easurements have been carried out on a model polymer blend, whose cons tituents are a poly-isobutylene and a polydimethylsiloxane, both trans parent and Liquid at room temperature. When compared with each other, the values of interfacial tension obtained from the different methods show a good quantitative agreement. Excellent agreement is also found with results for the same system previously published in the literatur e.