Effect of molecular weight on the rheological properties of atactic poly(vinyl alcohol)/dimethylsulfoxide/water solution

Abstract

This article describes the molecular weight effect of atactic poly(vinyl alcohol) (a-PVA) on the rheological properties of 7.5, 10.0, and 12.5 g/dL solutions of a-PVA with number-average degrees of polymerization (P n ) of 4000 and 1700 in dimethylsulfoxide/water mixture. a-PVA with a P n of 1700 solutions exhibited almost Newtonian flow behavior, whereas high molecular weight a-PVA, with a P n of 4000 solutions, exhibited shear-thinning behavior. On the plot of storage and loss moduli of a-PVA with a P n of 1700 solutions, the dynamic storage modulus of a-PVA, with a P n of 1700 solutions, was smaller than the dynamic loss modulus over the frequency range of 10 Ϫ1 to 10 2 rad/s. However, the dynamic storage modulus of a-PVA, with a P n of 4000 solutions, was smaller than the dynamic loss modulus in the sol state and, in the postgel state, the dynamic storage modulus became larger than the dynamic loss modulus, indicating the evolution of viscoelastic solid properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: [41][42][43][44][45][46] 2004

Rheological behaviors of PVA/H2O solutions of high‐polymer concentration

“…Lyoo et al12 studied the rheological properties of PVA solutions of 7.5, 10.0, and 12.5 g/dL with degrees of polymerization of 4000 and 1700 in dimethyl sulfoxide (DMSO)/H 2 O mixtures. They found that PVA solutions with high molecular weights and high polymer concentrations develop molecular orientation more easily by shear.…”

Flow Instability of Polyvinyl alcohol)/Dimethyl Sulfoxide Solution under Steady Shear

“…The dynamic competition between disentanglements and entanglements will be further complicated in the PVA solutions due to the intra-and inter-chain hydrogen bonding. The orientation reduces the entropy of the system in a manner analogous to the reduction of entropy in the kinetic theory of rubber elasticity 16 . At low temperatures, such an abrupt decrease in viscosity at high shear rates may be attributed to flow-induced weak network formation assisted by hydrogen bonding 17 .…”

Self-Stratified Films Obtained from Poly(methyl methacrylate/n-butyl acrylate) Colloidal Dispersions Containing Poly(vinyl alcohol): A Spectroscopic Study

“…For instance, pVOH has been used to stabilize colloidal latex particles against flocculation in aqueous media by entropy-driven adsorption on the particle surface displacing preadsorbed surfactants . Previous studies also indicated that the viscosity of pVOH solutions is mainly affected by the molecular weight and polymer concentrations. − In view of these considerations, we synthesized poly(methyl methacrylate/ n -butyl acrylate) (pMMA/ n BA) colloidal particles in the presence of pVOH and examined the effect of pVOH on the formation and stability of colloidal dispersions, the distribution of individual components, and mobility of these components during coalescence. The ability of pVOH to interact with water and colloidal particles facilitates slower evaporation rates that may also alter organization of individual components during coalescence, thus providing an opportunity for controlled self-stratification and consequently useful surface/interfacial properties.…”