Characterization of the Internal Pore Structures of Cotton and Chemically Modified Cottons by Gel Permeation

Abstract

The pore structures of cotton and formaldehyde-modified cottons have been characterized by applying the principles of gel permeation to chro-matographic columns formed of the finely divided fibrous cottons. Measurements were made of the relative elution volumes of suitable solutes which cover a range of known, discrete molecular weights. The solutes chosen were sugars ranging in molecular weight from 198 to 738, the elution volumes of which are in an inverse linear relationship to their molecular weights. Extrapolations of this linear relationship provide measures of the effective internal solvent volumes and the permeability limits of the cotton celluloses. Changes in these parameters are indicative of the nature and extent of the alterations of the pore structure produced by cross-linking. Marked differences have been found in the pore structures of cotton cross-linked to progressively higher levels with the fibers in a collapsed state by a bake-cure process and with the fibers in a semidistended state by reaction in an acetic-hydrochloric acid medium. The technique will be useful for relating changes in pore structure to the modifications of physical and performance characteristics of fabrics produced by various chemical treatments.