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Ordering in solutions of poly (vinyl alcohol) in water as detected by light scattering

1974; Wiley; Volume: 44; Issue: 1 Linguagem: Inglês

10.1002/polc.5070440113

1936-0959

E. Gruber, B. Soehendra, J. Schurz,

Material Dynamics and Properties

Abstract The tendency of poly (vinyl alcohol) in water to form aggregations was studied by light‐scattering measurements. On standing at 25°CC for several days an organized phase structure was formed. This could be seen in a change of the scattering functions (angular dependence of scattered light). At small scattering angles intensity increased and weak side maxima showed up in the scattering functions. This aging process is also characterized by negative A 2 ‐values, by a decreasing limiting viscosity number, and by increasing Huggins‐ k ′‐values. Speed and character of this change was found to be dependent on the concentration of the solution and the molecular weight of the sample. Models are discussed, which can lead to the observed irregular scattering functions. The most probable explanation is, that during aging gel particles are formed, which have a negative surrounding function, which has an analogous effect as weak repulsion.