Viscosity behavior of the polyelectrolyte poly(vinyl alcohol) having some intrachain crosslinks

Abstract

Abstract The viscosity behavior of aqueous poly(vinyl alcohol) (PVA)‐borax‐NaCl systems was investigated. The intrinsic viscosity [η] of PVA in borax solution increases with increasing borax concentration. In solutions containing both borax and NaCl, on the other hand, [η] decreases with increasing concentration of NaCl, and at high NaCl concentration phase separation is observed. In the absence of borax, [η] is nearly independent of the NaCl concentration. These results are interpreted in terms of a limited chain expansion due to charges and intrachain crosslinks simultaneously introduced in the PVA chain when the chain is complexed with negatively charged tetrahedral borate ions. The crosslinking density was estimated from the intrinsic viscosity [η] ∞ at infinite ionic strength using the Kuhn and Majer equation.