Noriyuki Sakamoto

Dilute solution properties of poly(4-hydroxystyrene)

Light-scattering and viscosity measurements have been carried out on dilute solutions of poly(4-hydroxystyrene) (PHS) fractions, which were obtained by hydrolysis of poly(4-acetoxystyrene) (PAS). The Mark-Houwink-Sakurada equations were determined in dioxane, tetrahydrofuran, isobutyl acetate and ethyl propionate at 25°C. The unperturbed dimension and the thermodynamic interaction parameters for PHS in various solvents were also determined and compared with those previously obtained for PAS. It was concluded that the hindrance potential of rotation around the C-C bond in the main chain of PHS is influenced more than expected solely from the volume effect of side groups, but it is within the same range found for other polar para-substituted polystyrenes. Also, it was found that in contrast to the PAS-solvent system there are significant energetic and entropic interactions between segments of PHS and solvent molecules, arising from the presence of a hydroxyl group in the side chain.

Unperturbed dimension of poly(4-acetoxystyrene) measured in good and theta solvents

Abstract In order to obtain the additional data concerning the unperturbed dimension of poly-4-substituted styrene, light scattering measurements are performed on the twenty-two fractions with molecular weight of (0.91–352)·104 of poly(4-acetoxystyrene) in dioxan at 25°C, from which the molecular weight obtained was found easily to be evaluated with the gel permeation chromatography using THF. Phase separation experiments for this polymer indicate that the theta state is attained in isopropyl acetate at 19.7°C and butyl acetate at 26.8°C. By making viscosity measurements at that state, the value of KΘ is directly evaluated as 5.4·10−4 dl g−1. The limiting viscosity number is also obtained in good solvents, THF and dioxan, at 25°C and constants of the Mark-Houwink-Sakurada equation in each solvent are determined. Further, approximately the same KΘ as above is obtained from these data with the Stockmayer-Fixman plot. The calculated value of steric factor, 2.37, on this polymer may be plausible, compared with those of polyvinylaromatic derivatives.

Viscometric studies on the methyl cellulose-sodium dodecyl sulphate complex in aqueous solution

Abstract Interactions between sodium dodecyl sulphate (SDS) and methyl cellulose (MC) with a molecular weight of 7.0 × 104 were studied in aqueous solution at 25°C by viscometry and equilibrium dialysis. Except for some details, the resulting adsorption isotherm was similar to that determined by Lewis et al. In contrast to other non-ionic polymers, the intrinsic viscosity of MC decreased to a minimum near the critical micelle concentration of SDS with increase in SDS concentration. It was concluded that the hydrophilicity of MC decreases by binding of SDS and that saturation of binding occurs at 15 mM, as correlated with peculiar Huggins plots found for this system.