Accession Number : ADA324445
Title : Rheology and Phase Behavior of the System PBZT-Phosphoric Acid-Water.
Descriptive Note : Final rept.,
Corporate Author : BRISTOL UNIV (UNITED KINGDOM) H H WILLS PHYSICS LAB
Personal Author(s) : Keller, A. ; Odell, J. A. ; Fischer, H.
PDF Url : ADA324445
Report Date : FEB 1997
Pagination or Media Count : 15
Abstract : Our assignment was to map out the viscosity of PBZT in a suitable solvent as a function of temperature, concentration, and shear rate. The richness and associated complexity of the system, however, forced us to place the matter in a much broader framework. Which, thanks to our wide ranging and possibly unique experience into this system, we were in a position to do. As PBZT is difficult to dissolve the choice of solvent is very limited. The most common is polyphosphoric acid used also in synthesis, characterization and processing. This solvent, as our studies have shown, is itself a complex system of polyphosphoric acids of different degrees of polycondensation and water in equilibrium, itself affected by temperature. In fact, in the polycondensation degrees used in the processing of PBZT, it is a mixture of orthophosphoric acid (OPA) and diphosphoric acid (DPA). This, with PBZT as a solute, gives rise to a complex phase diagram involving a variety of phases as previously investigated here. Any meaningful interpretation of measured viscosity values will need to refer to this phase diagram, the variation of viscosities with temperature and concentration (and to a lesser extent with strain rate) is strongly related to the phase behavior.
Descriptors : *WATER, *PHASE STUDIES, *RHEOLOGY, *VISCOSITY, *PHOSPHORIC ACIDS, SHEAR PROPERTIES, SYNTHESIS, POLYMERS, PROCESSING, STRAIN RATE, VARIATIONS, SOLVENTS, PHASE DIAGRAMS, CONDENSATION, UNITED KINGDOM.
Subject Categories : Organic Chemistry
Distribution Statement : APPROVED FOR PUBLIC RELEASE