Unperturbed dimensions and interaction parameters of poly(vinyl alcohol)s in water–acetone and water–tetrahydrofuran mixtures

Abstract

The intrinsic viscosities [η] of poly(vinyl alcohol)s (PVAs, which are biocompatible polymers)—with different (high, medium, and low) molecular weights were measured at 293–303 K in water (good solvent)–acetone (ACE, poor solvent) and water–tetrahydrofuran (THF, poor solvent) mixtures. The results observed, particularly the values of the Huggins constant (KH), indicated that the solvency of each PVA varied as a function of solvent composition (ΦACE/ΦTHF) and temperature. The unperturbed dimensions (Kθ) of the PVAs under nontheta conditions in a variety of water–acetone and water–tetrahydrofuran solutions were also calculated using various equations. The values of Kθ obtained via three different equations, i.e., those of Burchard–Stockmayer–Fixman (BSF), Berry, and Inagaki–Suzuki–Kurata (ISK), agreed well except for a few solvent compositions. The molecular extension factor (αn) and actual end-to-end distance (αnKθ) of each PVA were also computed.