| Abstract: | Rheological properties of selected poly(organo)phosphazenes have been studied using capillary rheometry. Melt viscosities of polymers were calculated as a function of shear stress and shear rate. Thermal stability was also studied. In the range of shear rate studied, all polyphosphazenes showed shear thinning behavior. The power law model was fitted to the data to get the power law index and the consistency index. Poly[bis(phenoxy)phosphazene] showed a Newtonian plateau at low shear rates whereas poly[bis(trifluoroethoxy)phosphazene] and poly[bis(p-phenylphenoxy)phosphazene] which exhibited liquid crystalline character were shear thinning even at low shear rates. Solid state capillary extrusion of polyphosphazenes was found to be more successful in fiber formation than other “state-of-the-art” processes, such as gel-spinning. The molecular weights of all polyphosphazenes synthesized were found to be too low for, Couette fiber spinning. Chemical, physical, and morphological studies were made on all fibers prepared. Many investigative techniques, such as X-ray diffraction, differential scanning calorimetry (DSC), density measurements, scanning electron microscopy (SEM), optical microscopy, solution nuclear magnetic resonance (NMR) spectroscopy, and gel permeation chromatography (GPC) analysis are featured in this paper as characterization tools. |
