A technique for obtaining differential infrared absorption spectra of chemically modified cottons is described, and its value illustrated by selected examples. With KBr discs in a double-beam spectrophotometer, absorption bands common to unmodified and modified cottons can be reduced in intensity by placing equivalent quantities of cellulose in both beams. The resulting spectrum facilitates identification of the molecular species introduced in making the derivative. The method is useful in obtaining spectra of the reaction products of cotton and intermolecular crosslinking agents at low degrees of add-on. Application of the method to cotton reacted with compounds of the dimethylol urea type and with other agents is described.
Elizabeth R. McCall, Sylvia H. Miles, Verne W. Tripp, and Robert T. O'Connor, "Differential Infrared Spectroscopy of Chemically Modified Cottons," Appl. Spectrosc. 18, 81-84 (1964)