For cellulosic fibers (7) these include the ionic product for water Kw; either the acidic dissociation constant for cellulose, KA, or the basic dissociation constant, KB, where KB = KA + Kw; the availability of Cell-OH (actually glucose residues) for provision of internal surfaces (41% for cotton, 74% for viscose rayon), which percentages are a function of fiber mor- phology, crystallinity and amorphous character; the concentration of Cell-OH residues; the concentration of acidic, car- boxylate groups in cotton and viscose rayon and the volume of the surface phase in liters per kilogram of fiber (for cotton and viscose rayon: 0.22 and 0.45). These latter values are known as volume term