Static and Dynamic Light Scattering from Poly(vinylbutyral) Solutions: Effects of Aggregation and Solvent Quality

Static and dynamic light-scattering data were obtained from poly(vinylbutyral) in the solvents MeOH and 1:1 and 9:1 MIBK/MeOH by volume. Concentrations spanned the dilute and into the semidilute regimes. From the static data were calculated second viral coefficients (A2) and z-average mean-square radii of gyration ((s2)z). These data yield the order of solvent quality 1:1 MIBK/MeOH > 9:1 > MeOH. Static data are combined with dynamic data to determine the friction coefficients, f for polymer/solvent mutual diffusion. In the dilute regime, values of f are greatest not in the best solvent (1:1) in which the polymer domains are largest (highest (s2)z) but in the 9:1 MIBK/MeOH mixture. This result is attributed to the effects of inter- and intramolecular association which are most severe in the latter solvent. © 1987, American Chemical Society. All rights reserved.