Thermoanalytical Studies on the Durable-Press Curing of Cellulose

Abstract

In the course of a series of thermoanalytical investigations on durable-press curing processes for cotton, attention has been focused on the acid salt catalysts. Studies on the sequence and nature of the chemical events occurring during heating through the tem perature range of a typical durable-press cure have been carried out by using differential thermal analysis ( DTA ) and thermogravimetric analysis (TGA). Different methods of combining cotton and salt were compared. In one sequence, cotton was soaked with aqueous salt solutions; in another, the two solids were separated from each' other by a porous barrier. In a few instances, an aminoplast cross-linking resin was included in the reaction system.

Among the detectable processes, when nitrate salts were used, was a strongly exo thermic reaction accompanied by a rapid weight loss, not characteristic of any one of the substances in the mixtures. This decomposition could be modulated with respect to temperature, rate, and extent, depending on the concentration, environment, and geo metric arrangement of the system. In an attempt to explain these effects additional studies on zinc nitrate were carried out showing that its thermal behavior was not what might be implied from values stated in the cited literature. On the basis of the accumu lated data, it is suggested that the exothermic decomposition is the consequence of the oxidative attack of NO₂ on cellulose, the former being produced by the thermal breakdown of the nitrate salt.