Robert H. Barker

Principles of Reactivity of Nitrogenous Agents with Cotton

A new approach to circumvent the direct relationship between the reactivity of N-methylol agents and hydrolysis rates of the cellulose derivatives under acidic conditions has been studied. To achieve a more durable product from a reactive agent with cellulose, an irreversible system was sought through incorporation of a suitable leaving group, such as acetoxy, to activate the agent. Reactivities of acetoxymethyl, hydroxymethyl, and methoxymethyl derivatives of N-methyl-2- imidazolidinone (MI), methyl carbamate (MC), and benzamide (B) have been compared under selected, acidic conditions. Reactivity contributed by carbonium-immonium ion stability is in the expected order (parent amide given) MI>>MC>B. Reactivity is significantly altered by the leaving group and is in the order acetoxy >> hydroxy >> methoxy. Substrates for reactivity studies included isopropanol, water, and cotton. Acetic acid released by reaction with these substrates and an acetoxy derivative had only a minor catalytic effect upon the reaction rate except in the fabric treatments carried out in the presence of magnesium chloride. Acetoxy-derivatives of similar polyfunctional agents are similarly activated as long as the acetoxy groups are isolated from one another; however, vicinal diacetoxy glyoxal resins appear to be of the same general order of reactivity as the corresponding dihydroxy derivatives. Use of these active agents in nonaqueous solvent systems is suggested and limitations for use in aqueous systems are discussed.

Flammability of Cotton-Polyester Blend Fabrics

Cotton-polyester blends pose a special flammability problem because the thermal and mechanical properties of the fibers are so different. Cotton tends to char on heating but generally maintains some structural integrity; polyester normally melts and flows at temperatures of ca. 260°C. If a mixture of the two fibers is burned, the molten polyester frequently tends to wick on the cotton char, resulting in the phenomenon of scaffolding detailed by Kruse.(1) Because of these effects, it is impossible to predict a priori the flammability of the blend on the basis of the behavior of the individual component fibers; thus, Tesoro and Meiser(2) have shown that needle-punched webs prepared from 50:50 blends of cotton and polyester exhibited oxygen indices lower than those of either fiber alone in a similar structure. The hazard in the case of apparel may be further increased by the tendency of the molten polyester to cling to the body of the person wearing the garment, thus causing severe burns on its own.

A Flame Retardant Coating for Textile Applications

a powdered compound containing 50+% bromine, an antimony oxide synergist, and an acrylic binder. Softeners, permanent press resins, and emulsifiers are also frequently required to produce desired esthetic properties. Because of the flammability of the softeners, binder and other resins, higher levels of bromine/antimony oxide are required for the complete finish than when the flame retardant is used alone. The increased amount of flame retardant leads to processing problems, worsened hand and higher costs. However, if the flammability of the added components could be reduced, then the level of flame retardant could also be decreased. This paper reports the results of an investigation into decreasing the flammability of the acrylic binder. A series of experiments was initiated to design and develop suitable flame retardant latices. A bromine-containing binder was preferred since antimony oxide