The viscosity of immiscible polymer blends has been studied via application of certain aspects of rheology. A symmetric mixture rule was derived, and the deviations from the 'additivity rule' have been associated, essentially, with the properties of the interphase, with its influence on the effective volumes of the two polymers constituting the blend and with the deformability of both the interphase and the disperse phase. The rule predicts a positive deviation for a mixture with a disperse-phase viscosity (r/a) greater than that (r/m) of the continuous medium, and a much higher-viscosity interphase, i.e. r/i >> r/d/> r/re" Negative deviation is to be expected when the interphase has a much lower viscosity than those of the two pure polymers (r/a, r/m>>r/i) in the blend. The viscosity and strength of the interphase depend mostly on the specific thermodynamic interactions that led to its creation.
Посилання на статтю:
The viscosity of immiscible polymer blends: influences of the interphase and deformability / E. U. Okoroafor* and J.-P. Villemaire and J.-F. Agassant // Polymer. – 1992. – Vol 33. – P. 5264-5271.