Equilibrium adsorption of two direct cotton dyes on cellulose oxidized with specific oxidizing agents and by the products of reduction of these oxycelluloses, under standard conditions of dyeing has been studied. It is shown that conversion of hydroxyl groups of cellulose to carbonyl groups does not influence dye adsorption, but formation of ionizable carboxyl groups in cellulose chain molecules brings about an appreciable reduction in dye uptake, the extent of reduction being independent of the position in the glucose units of cellulose at which the carboxyl group is formed. Based on a theoretical treatment, it is shown that only a fraction of the total carboxyl groups is responsible for the reduction in dye adsorption under specific conditions of dyeing, and with progressive increase in the total carboxyl content of cellulose, the value of this fraction goes on decreasing continuously.

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SynopsisThe oxidative susceptibility to different oxidizing agents such as dichromate-sulfuric acid, dichromate-oxalic acid and sodium hypochlorite in presence of leuco Cibanone Orange R of cellulose oxidized with sodium metaperiodate and its corresponding borohydride-reduced product was studied and compared with that of cellulose. From the changes in the chemical properties of the oxidixed products, an attempt was made to study the mechanism of oxidation of periodate oxycellulose and sodium borohydride-reduced periodate oxycellulose with the above mentioned oxidizing agents.

EXPERIMENTAL Adsorption Rate DeterminationsThe desired weight of carbon is placed in a. glass-doppered Erlenmeyer flask large enough to allow the adsorbent to form a thin layer a t the

synopsisThe changes in physical properties such as moisture regain, tensile strength, elongation at break, bursting strength, and resistance to abrasion of cellulose modified with different oxidizing agents such as dichromatesulfuric acid, sodium hypochlorite in presence of leuco vat dyes, and potassium metaperiodate and of the corresponding products obtained as a result of reduction with sodium borohydride and those by oxidation with chlorous acid have been studied. Results are critically discussed in the light of existing knowledge on the changes that occur in the fine structure as well as in the chemical structure of cellulose during the mentioned modifications. I t i pointed out that complex changes in physical properties of cotton cellulose brought about by chemical modification could hardly be evaluated and interpreted in terms of one or two physical or chemical parameters.