Measurements of the IR spectra of native cotton linters and hydroxyethyl cellulose samples of different ethoxyl contents indicated that weaker-bonded OH groups are present in hydroxyethylated cellulose of ethoxyl contents of 23.34—28.89%. Also, the crystallinity indices, mean hydrogen bond strengths, and asymmetry indices for these hydroxyethylated celluloses are 100 compared with native cellulose; however, at ethoxyl content 30.31%, the crystallinity index increased; that is, a higher state of order is formed. The dielectric constant, ′, of native and hydroxyethylated cotton linters was measured at different temperatures and frequencies. The results indicate that the values of the dielectric constants of all hydroxyethyl cellulose samples at a given frequency are increased with the increase of temperature and become greater than ′ of native cellulose. At relatively low ethoxyl contents, the dielectric constant depends mainly on increasing the formed amorphous regions of the cellulose as a result of hydroxy-