The reaction of polycarboxylic acids with cotton at elevated temperature has been investigated as a function of partial neutralization of the carboxylic acid with sodium carbonate or triethylamine. A high level of cellulose cross-linking was realized with a variety of polycarboxylic acids having three or more carboxyl groups per molecule, although only partial esterihcation of the carboxyl groups occurs in this process. The use of polycarhoxylic acids in the form of their partial salts results in broader applicability of this rapid esterification process of cross-linking, in improved add-ons and performance characteristics of the modified cotton, and in reduced acid tendering of the treated fabrics.

Ester cross linkages in cotton cellulose have been investigated for mobility (trans esterification) at elevated temperature. Cotton cellulose polycarboxylates were prepared by reaction of cotton print cloth with polycarboxylic acids having 3-6 carboxyl groups per molecule, at least two of the carboxyl groups being on adjacent carbon atoms. Durable creases were developed to various degrees when these fabrics were subjected to thermal creasing treatments subsequent to the cross-linking reaction. Thermal mobil ity of ester linkages in selected model compounds has been shown to result from participation of the unesterified carboxyl group adjacent to the ester linkage. The cyclic anhydride was detected from dissociation of model ester compounds at elevated tempera tures; similar cyclic anhydrides are the probable intermediates in transesterification of ester linkages in cotton cellulose polycarboxylates.

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An uncatalyzed reaction of formaldehyde with cotton cellulose at 125°C is described, and the fabric properties of the product are characterized. It is shown that this formaldehyde-modified fabric had a more homogeneous distribution of cross linkages in the fiber structure than the product from a boric acid-catalyzed reaction conducted under similar conditions. The more homogeneous distribution of cross linkages is particularly favorable for the development of high wrinkle recovery angles.