Donald M. Soignet

Modifications of Cotton Cellulose Surfaces by Use of Radiofrequency Cold Plasmas and Characterization of Surface Changes by ESCA

Radiofrequency (rf) cold plasmas of argon, nitrogen, and air were used to modify cotton fabrics and yarns. Changes in surface characteristics were detected by application of the techniques of electron emission spectroscopy for chemical analyses (ESCA), electron spin resonance, and chemiluminescence. Examples of polymeriza tion of selected monomers and depolymerization of chemically modified cottons within rf plasmas have been used to illustrate potentials of combinations of plasmas and ESCA in cellulose chemistry.

Comparison of Properties of Anion-Exchange Cottons in Fabric Form

The effects of the substitution of various types of amino groups in cotton on the crease recovery properties have been investigated. The potentiometric titration curves of the various aminized cottons have been used to differentiate the presence of quaternary ammonium groups (strong-base anion exchangers) from the presence of primary, sec ondary, or tertiary amino groups (weak-base anion exchangers). Weak-base anion exchange cottons have been quaternized by treatment of cotton containing tertiary amine groups with methyl iodide and with epichlorohydrin. In addition, strong-base exchangers have been prepared directly by a one-step process in which cotton pretreated with a base is reacted with a mixture of epichlorohydrin and a tertiary amine at a 3: 1 molar ratio. Weak-base aminized cottons containing primary amino groups have been reacted with epichlorohydrin in the presence of an aqueous base to form cottons of improved dry- and high wet-crease resistance. Only those quaternized cottons prepared from the reaction of pure epichlorohydrin on cottons containing tertiary amine groups possessed both high dry- and improved wet-crease recovery properties. Equations are given to illustrate types of reactions investigated and mechanisms of reactions.

Anion-Exchange Cottons Prepared from Sodium Cellulosate1

Sodium cellulosates containing from 0.5-1.9 mequivs of Na+ per gram of fabric were prepared by reacting cotton in methanolic solutions of sodium methoxide. The sodium cellulosates were reacted with β-chloroethyldiethylamine in t-butanol to form diethylaminoethyl (DEAE) cottons of greater than 1.0% nitrogen. These DEAE -cottons, easily pre pared at room temperature, were readily converted to the quaternary-base cellulose anion exchangers. Quaternary-base anion exchangers of lower capacity were prepared by reacting sodium cellulosates with glycidyltrimethylammonium chloride. Anion exchangers prepared in nonaqueous media did not differ in fabric properties from anion exchangers of similar capacities prepared in aqueous media. Ability of amino groups to catalyze cellulose-epoxide reactions was not significantly different in DEAE-cottons prepared in nonaqueous and in aqueous media.

Electron Spectroscopy for Chemical Analyses (ESCA) of THPOH-NH3-Treated Fabrics

Induced-etectron-emission spectroscopy was shown to be a tool capable of detecting chemical changes that occur during storage of flame-retardant cottons. This information will aid in the understanding of the oxidation process and lead to the development of durable name retardants for cotton.

Nuclear Magnetic Resonance Studies of Ethyl N -Substituted Carbamates

Nuclear magnetic resonance studies showed that ethyl N-substituted carbamates are present as single isomers in either deuterated chloroform or dimethylsulfoxide solvents. The thioncarbamates exist as cis-trans isomer mixtures. The polar and resonance character of the substituent affects the shielding and thus the chemical shift of the amide proton.

Solvent Finishing of Cotton and Cotton-Polyester Blends Part I : Binary Aqueous Azeotropes as Solvents for Dimethyloldihydroxyethyleneurea

Azeotropes of low watercontent that boil at less than 100°C were selected as solvents fordimethytotdihydroxyethytene urea and zinc nitrate catalyst in the chemical modification of cotton and cotton-polyester blends. Fabrics were treated by the usual pad-dry-cure techniques, and final properties were compared with those obtained by conventional all- aqueous systems.

Internal Catalyst for the Modification of Cotton Cellulose with Dimethylolethyleneurea

DEAE-cotton containing approximately 0.90% nitrogen was prepared by a modification [4] of the Hartmann [2] method. The fabric was padded twice to 100% wet pickup with a 20% aqueous solution of 2-chloroethyldiethylamine hydrochloride and then immersed in aqueous 8% NaOH solution at 95°C for 10 min. The treated fabric was soaked in dilute acetic acid to remove excess base. To convert to the hydroxide or chloride forms, the fabric was soaked overnight in 0.01 N NaOH

The Effects of Plasma Irradiation on Saccharides

Abstract Monosaccharides and polysaccharides are chemically modified when they are subjected to rf plasmas derived from oxygen, nitrogen, or argon. The plasma treatment converts hydroxyl groups within the bulk to carbonyl groups on the order of one per anhydroglucose unit. On the surface, the concentration of carbonyl groups is greater than in the bulk. The activated surfaces formed by the plasma treatments are stable for at least 1.5 h. The observed spectral (IR, ESCA, and ESR) changes of the irradiated samples are the direct result of the plasma and not the secondary result of plasma-activated surfaces reacting with the atmosphere.

Salts of DEAE-Cottons as Built-in Catalysts for the Cellulose-DMEU Reaction

The use of a built-in tertiary amine salt as a catalyst for the reaction of cotton with substituted cyclic ureas has been investigated, with emphasis on the reaction of 1,3-bis(hydroxymethyl)-imidazolidinone-2 (called dimethylolethyleneurea or DMEU). Both organic and inorganic acid salts of diethylaminoethyl (DEAE) cotton have been found to be catalytically active. The effects of reaction temperature, concentration of reagent in the pad bath, and solvent media were studied. DEAE-cotton in the hydroxide form catalyzed the DMEU-cotton reaction only in 1,3-dichloro-2-propanol solvent. The very reactive DMEU could be used as finishing agent in a delayed-cure process with the hydrochloride of DEAE-cotton. A similar tertiary amine hydrochloride catalyst, introduced as an external catalyst in the pad bath, was found to be unsuitable for the delayed-cure process with DMEU.

Sodium Cellulosate and Diethylaminoethylcellulose as Substrates for Modification of Cotton with Epoxides

Sodium cellulosates containing up to 1.8 milliequivalents Na+ per g fabric were prepared by reacting methanolic solutions of sodium methoxide with solvent exchanged cottons which had been preswollen in water, dimethlformamide or in 23% aqueous NaOH. These sodium cellulosates were reacted with five difunctional epoxides in t-butyl alcohol or in perchloro ethylene. Fabric properties were compared with those obtained when the five epoxides were reacted with diethylamino ethyl celluloses (DEAE-cottons). DEAE-cottons were prepared in nonaqueous media by reacting the sodium cellulosates with β-chloroethyidiethylamine in t-butyl alcohol solutions. The free amine form as well as the hydrosalt form of DEAE- cottons was used as substrate for epoxide reactions. Fabric properties were also compared with those obtained with the hydrosalt form of DEAE-cottons prepared in aqueous media and with those resulting from the reaction of epoxide with cotton pretreated with aqueous XaOH.