Katsumasa Kaneko

Average molecular weight and viscosity of acetone solutions of phenolic resins

SummaryThe viscosity-diffusion method has been proposed as a technique for molecular weight determination of spherical polymers such as phenolic resins. When the average diffusion coefficient DA calculated from the area of diffusion curve is used in this technique, there exists the following relation between Da and the specific volume φ of solute in solution: φ √DA = const. therefore, [η] = K M0.2 is derived. Though the average molecular weight obtained from DA and φ generally falls between Mn and Mw, there are some reports that the exponent of M rather increases when M is given as number average. We found that the exponent becomes larger than 0.2 when the polymolecularity of the sample becomes remarkable or it increases with molecular weight.

Diffusion phenomena of small molecules in polyelectrolyte solutions

SummaryFrom diffusion data of xylose in poly (acrylic acid) and in poly(sodium acrylate) aqueous solutions, the behaviour of these polymers in solution is discussed. When these polyelectrolytes are ionized and expanded in water, consequently, the diffusion phenomena of xylose in these solutions follows the theory of linear macromolecules in solution. When NaCl is added in poly (acrylic acid) solution, the polymer chain contracts and becomes spherical. Therefore, xylose cannot pass through the polymer domain. With poly(sodium acrylate), however, an effect of salt has not been found. Furthermore, effects of neutralization are discussed.

The Diffusion Curve and the Average Diffusion Coefficients of the Polymer Solution of Polydisperse Systems

高分子溶液の拡散曲線は,拡散係数が一般に濃度依存性をもつためにひずむのが普通であるが,本報においては拡散係数の濃度依存係敷が成分によって異なる場合の数式的取り扱いを示し,濃度依存性の影響を除去した平均拡散係数の求め方を述べた。いわゆるモーメント法と面積法とによる平均拡散係数の比はしばしば不均一度の表示に使用されるが,これも濃度依存性を除去してはじめて正しい意味を持つことが明らかにされた。