Viscosity measurements are made on aqueous borax solutions of poly(vinyl alcohol) (PVA) samples over a wide range of PVA concentration, C, to examine the hydrodynamic properties of associated polymers compared to those of neutral polymers. The dynamic viscoelastic data are reanalyzed using a statistical-mechanical theory for elastically effective chains in transient gels developed by Tanaka and Ishida. The viscosity data are not superposed in the plot of viscosity against C[η] using the Huggins relationship, especially around and over a critical concentration, CN, at which the dynamical behaviors drastically change and an inflection point of a curve in the plot of the viscosity against C is located. On the other hand, when we assume that the chain dimension around CN is the unperturbed one, the viscosity data around CN is well-superposed on a curve in the plot of viscosity against C/C*up, where C*up is the overlapping concentration of the unperturbed chain. The inflection point of this composite curve is located at C/C*up = 1, which infers that CN corresponds to the overlapping concentration. All data of the density of elastically effective chains, νeff, are superposed on a curve in the plot of νefflν against (C - CN)/CN where ν is the density of polymer chains, which implies that CN should be regarded as a kind of gel point. Some discrepancies between the experimental data and the theoretical curve were observed, some of which cannot be explained using the pairwise association of PVA chains.
|Number of pages||8|
|Publication status||Published - Jan 27 1998|
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry