Phase separation state in hemicellulose and lignin blends analyzed by contact angle measurements

Abstract

AbstractThe phase separation states of hemicellulose and lignin in their blends were investigated by means of contact angle measurements. The hysteresis behavior in dynamic contact angles suggested that a phase separation of cluster‐state type (not of random dispersion type) took place at hemicellulose‐rich and lignin‐rich mixing ratios. It may be caused by the low cohesive force between hemicellulose and lignin molecules. Further, the total surface tension, and the balance between dispersion and polar forces in the total surface tension were evaluated from the equation of Wu. It was found that in the region of a hemicellulose‐rich mixing ratio, the polar and dispersion forces of the surface tension of the solid were reduced and raised, respectively, and in contrary to this, in the lignin‐rich region, the former were raised and the latter were reduced. The polymer‐polymer interaction parameter of Flory between hemicellulose and lignin depends on the mixing ratio as reported previously; this may be ascribed to a difference of the balancing of polar‐dispersion forces.