Rheological behavior and microstructure of 2,2′‐dioxy‐ 1,1′‐binaphthylphosphazene R/S random copolymer |
| |
Authors: | J. Canales M. E. Muñoz A. Santamaria J. L. García‐alvarez G. A. Carriedo |
| |
Affiliation: | 1. Polymer Science and Technology Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, P.O. Box 1072, 20080 San Sebastián, Spain;2. Departamento de Química Orgánica e Inorgánica, Facultad de Química, Universidad de Oviedo, Oviedo 33071, Spain |
| |
Abstract: | Solutions of a binaphthoxy phosphazene copolymer (containing chiral 2,2′‐dioxy‐1,1′‐binaphthyl units with 50% R and S configurations distributed along the chains) in N‐methyl pyrrolidone were studied by means of continuous flow experiments and small amplitude oscillatory flow tests. A sudden viscosity decrease was observed in the polymer concentration range (39–40 wt %), evidencing a liquid‐crystalline polymer behavior. This has been confirmed by other rheological methods which have demonstrated that, for a sufficiently high concentration, the solutions of the binaphthoxy phosphazene copolymer give rise to a lyotropic system with formation of rigid rods (axial ratio of 10) stacked parallel to each other. The lyotropic properties of our binaphthoxy phosphazene copolymer are compatible with a regular helical structure, similar to that found for a homoleptic binaphthoxy phosphazene, which contains only S configuration. This suggests that the chains of 50% R/S binaphthoxy phosphazene copolymer are, in average, close to the strictly alternating R‐S copolymeric structure of the syndiotactic isomer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010 |
| |
Keywords: | liquid‐crystalline polymers (LCP) lyotropic polyphosphazenes rheology |
|
|