Colloid Chemical Studies on Starching Materials. I. Structural Viscosity of Poly-Vinyl Alcohol Solution

Abstract

Abstract The structural viscosity is measured for the aqueous solutions of poly-vinyl alcohol-The relative viscosity, (η/ηw), shows linear relationship to the reciprocal of the rate of flow, Q: η=η_N+2.57×10^-5×P_0/Q where ηN and P0 are constants. P0 corresponds to the pressure to destroy a net-work structure in the solution, or an apparent yield value, and ηN corresponds to the viscosity coefficient of the destroyed structure, which is assumed to flow as Newtonian. As for the Newtonian viscosity ηN of polyvinyl alcohol solutions, [ηN] defined by [η_N]=1n(η_N/η_w)/C is independent on concentration, as far as measured. Comparing the intrinsic viscosities of specimens of the same polymerization, degree, the completely saponified specimen shows smaller value than partly saponified one. This may be explained by the decrease of molecular extension due to the strong intramolecular interaction of OH groups. The apparent yield values P0 is 0.5∼3.5 cm. H2O and is highly dependent on the history of the solution. The completely saponified specimen shows greater P0 value. It will also be explained by the strong intermolecular interaction of OH groups to form net-work structure.