EFFECT OF WATER ON VISCOSITY AND SHEAR-THICKENING BEHAVIOR OF TELECHELIC IONOMERS IN NONPOLAR-SOLVENTS

Quantitative effects of mater on the viscosity and rheology of magnesi um-and sodium-neutralized dicarboxy-terminated polybutadiene in toluen e are reported. A change in the water concentration from 50 to 500 ppm led to a viscosity decrease of 2 orders of magnitude for solutions ne ar the gel concentration. Because of the hygroscopic nature of ionomer solutions, rheological experiments were conducted in a humidity-free environment. The dynamic measurements show that the viscosity seductio n is related to a reduction in both the plateau modulus and the termin al relaxation time. The magnitude of shear-thickening decreases and th e onset of shear-thickening shifts to higher shear rates with increasi ng water content.