INTERFACIAL-TENSION IN POLYMER BLENDS .2. MEASUREMENTS

Interfacial tension is one of the most important parameters for unders tanding morphology developments in immiscible polymer blends. Although a great number of experimental methods is available for interfacial t ension measurements of low viscosity Newtonian fluids, most of these t echniques are not relevant to common industrial polymers. In this stud y, experimental results obtained using the so-called ''capillary break up method'' are reported for the blends made of high viscosity, indust rial polymers. The interfacial tension coefficient of PS/PMMA, LDPE/PS , LDPE/PMMA, PS/PA-6, PMMA/PA-6, EPR/PA-6, and EPR/PVDF, was determine d, frequently at several temperatures. The values determined in the pr esent study do not always agree with the data reported in the literatu re. The discrepancies can be explained by differences in polymer molec ular weights or molecular weight distribution as well as by the presen ce of additives (e.g., stabilizers, antioxidants, processing aids) use d in industrial formulations.