Critical behavior of the intrinsic viscosity of poly(vinylalcohol) solutions near the gelation point

Abstract

The critical behavior of intrinsic viscosity near the gelation point was experimentally examined for poly(vinylalcohol) (PVA) solutions. The constant of the Huggins equation for viscosity (k′) for PVA clusters was higher than that of linear PVA. The intrinsic viscosity ([η]) for PVA clusters was smaller than that of linear PVA at lower polymer concentrations, at which PVA solutions were prepared and cooled. The critical exponent of [η] was found to be 0.20. The weak divergence of [η] resembles the critical behavior of Zimm clusters predicted by the 3D percolation theory, or that of Rouse clusters by the classical theory of the Flory–Stockmeyer type. The critical behavior of [η] of PVA solutions, however, may be considered to be close to Zimm clusters of the 3D percolation theory rather than that of Rouse clusters by the classical theory, because Zimm clusters are more preferable than Rouse clusters for the description of the critical behavior of [η].