Search

An account is given of an investigation of the influence of dry heat on wool keratin. It is shown by three different chemical techniques that cross-linking occurs up to a temperature at which the amino-acid decomposition becomes marked. Although Iysinoalanine and lanthionine are shown to be formed, these amino acids do not appear to be major contributors to the cross-linking of the heated protein. The covalent binding of the e-amino group of lysine was determined quantitatively, and, from the results obtained, it is deduced that this group is involved to a large extent in the formation of cross-links. On the basis of these findings, it is postulated that amide cross-links are formed through the ε-amino group of lysine by reaction with carboxylic side chains of aspartic or glutamic acids or their amide derivatives. [ABSTRACT FROM AUTHOR]

Hydroxymethanesulfonic acid (HMS) is effective as a catalyst for durable-press finishing of cotton and polyester /cotton fabrics by pad-dry-cure, mild cure, and one-step dry-cure treatments. The catalyst is readily formed upon addition of sulfurous acid to pad baths containing free formaldehyde although it can be prepared separately. HMS is a strong acid and can be used in relatively small concentrations. The catalyst appears to be "self-limiting." It dissociates into volatile components during the curing treatment which makes afterwashing unnecessary to prevent changes in strength or wrinkle resistance.HMS catalysis of treatments with dimethylol methyl carbamate and formaldehyde crosslinking agents produced fabrics with high levels of durable-press properties. Mild-cure finishing at 100°C, and pad-dry-cure and one-step dry-cure finishing at 120-140°C were effective with this catalyst. [ABSTRACT FROM PUBLISHER]

The thermal behavior of diethylaminoethyl-substituted cotton celluloses was examined by thermogravimetric analysis, differential thermal analysis, and differential scanning calorimetry. Samples at levels up to 10% substituent content (prepared via an anhydrous sodium cellulosate method) were compared with other samples prepared by the conventional aqueous sodium hydroxide method. All thermal analyses were carried out in purified dry nitrogen or high vacuum at heating rates of 5-40°C/min. Considerable variation was observed when the samples in the base form were compared with those placed in the salt (hydrochloride) form. The effect of basic diethylaminoethyl groups on the cellulosic thermal degradation was shown in altered thermal patterns and ΔH of pyrolysis. In the hydrochloride form, lower Δ H of pyrolysis and decreased decomposition temperature were observed. These observations together with other minor thermal effects which were found to be associated with the decomposition, are compared with recent studies on the effect of inorganic bases on the pyrolysis of cotton cellulose. [ABSTRACT FROM PUBLISHER]

Differential scanning calorimetry and thermogravimetric analysis curves were obtained for cotton cellulose in the presence of both flame-retarding and nonflame-retarding compounds and evaluated quantitatively for ΔH, activation energy, total weight loss, and char remaining after pyrolysis. Twenty-three compounds were tested and were found to fall roughly into three groups: (I) those which do not undergo decomposition in the temperature interval in which cellulose decomposes (200-400°C); (II) those which decompose appreciably during or preceding this temperature range; and (III) those which do not interact in any way with cellulose. It was found that, with increasing molar add-on, heat liberated from cellulose decreased for group I, increased for group II, and was not a function of molar add-on for III.A study of the kinetics of decomposition for these systems indicates that, while the majority of reactions proceeded as a pseudo first-order process, there are several exceptions to the trend. As would be expected for a first-order process, activation energy was found to decrease with increasing flame retardancy.Further, it has been observed that the addition to cellulose of any of the compounds from the first two groups lowers the onset temperature of decomposition and the temperature at which the first major weight loss begins. This temperature decrease approaches some type of limiting value for all the compounds, and varies from compound to compound. In addition, a large increase in remaining char results from a very small add-on, and this, too, tends to approach a limiting value as add-on increases. [ABSTRACT FROM PUBLISHER]

Steaming has been established as a potentially simple method for elimination of free formaldehyde from carbamate-sensitized fabrics. The removal is quickly accomplished by this technique without adverse effects on the chlorine resistance and durable press properties of the postcured material. Factors affecting the presence of free formaldehyde and variations of the amount in sensitized fabric have been studied. Free formaldehyde in the pad bath from excess used in synthesis of the methylolated finishing agent and processing conditions employed for sensitization largely determine the free formaldehyde content of the sensitized fabric. Although formaldehyde is retained tenaciously by dry, sensitized cotton, it is released readily by aeration with humid air over relatively extended periods or very rapidly with steam in a few seconds. Another potential source of free formaldehyde is from dissociation of the finishing agent in the sensitized fabric during storage. However, with proper packaging of the fabric, there is little generation of free formaldehyde by this decomposition reaction. [ABSTRACT FROM AUTHOR]