A pretreatment method for dyeing Kevlar® fibers without dye carriers has been developed. Fibers were metalated by reacting with a methylsulfinyl anion, the metalated fibers were dyed with cationic and direct dyes, and the resulting coloration and physical properties were evaluated. The results show that this pretreatment technique can improve the dyeability of Kevlar without compromising mechanical properties. Metalation improved dyeability more than grafting with either adipoyl chloride, benzoyl chloride, or vinyl benzyl chloride.Kevlar is a para-aramid fiber with excellent characteristics of high tensile strength, elastic modulus, and inherent flame resistance. Keviar has thus been used for performance applications including firemen's turnout coats, race-car drivers' uniforms, military aircraft uniforms, hot gas filtration, laundry press covers, and industrial protective clothing. Further uses of this fiber in industrial apparel are limited by its low dyeability because of its highly crystalline structure [4]. There have been many attempts to dye aramids using a variety of solvents or dye carriers [ 2,6,8 ] . Dimethyl sulfoxide (DMSO), a highly polar solvent, is recognized as an excellent swelling agent for aramid fibers. Moore and Weigman [ 5 ] showed that the dyeing characteristics of Nomex° fibers were significantly improved by a DMSO pretreatment. Takayanagi and Katayose [ 10 ] reported a synthetic route to the chemical modification of the Kevlar fiber surface in order to introduce reactive pendant groups. This method has been applied to improve the fiber-matrix interface in composites [7], a synthesis involving a two-step metalation-substitution process.Our objective in this study was to develop a pretreatment method using the metalation technique to enhance the dyeability of Kevlar with cationic and direct dyes. ' Experimental An eight harness satin weave Kevlar fabric was obtained from Clark-Schwebel Company; samples were 3 cm X 25 cm. Prior to experimentation, the samples were placed in a Soxhlet apparatus and extracted with acetone for an hour, then were dried at 125°C for an hour in a vacuum oven, and stored in a desiccator.Anhydrous dimethyl sulfoxide ( DMSO ), sodium hydride (80% dispersion in mineral oil ), and adipoyl chloride were used as received from Aldrich Chemical Co. Benzoyl chloride (from Mallinckrodt Chemical Works), vinyl benzyl chloride (VBC, from Dow Chemical Co.), glacial acetic acid (from J. T. Baker Chemical Co.), and sodium sulfate (from General Chemical Co.) were used as received. Astrazong green MD/ L ( CI basic green 4 ), a cationic dye, and Siri use Supra turquoise blue GL 167 ( CI direct blue 86) both (from Mobay Corp.) were used as received.For the DMSO pretreatment, samples were immersed in 50 ml DMSO for 30 minutes at 70°C before dyeing. The metalation procedure was as follows: A three-necked flask was equipped with an N2 inlet, a drying tube, a magnetic spin bar, and a thermometer; 150 ml of DMSO and 0.3 g of sodium hydride were reacted for 10 minutes at room temperatu...

Because many pesticide handlers persist in wearing and reusing conventional workclothes, a renewable functional finish that enhances the pesticide-protective qualities of fabrics would be useful. This study investigated the ability of starch to act as a pesticide trap, preventing transfer and increasing removal by laundering, and the effect of carboxymethyl cellulose on release of pesticide in laundry. The retention and distribution of methyl parathion (MeP) on 65% polyester/35% cotton fabric was studied with four finishes: starch and carboxymethyl cellulose (CMC) as nondurable finishes; durable press resin (DP) and durable press/carboxymethyl cellulose (DP/CMC) as durable finishes. Starching with an add-on of 8% (w/w) effectively reduced the area of contamination and enhanced the removal of methyl parathion from polyester/cotton fabrics. Residual pesticide values for CMC, DP, and DP/CMC finishes were similar to that of the unfinished fabric. While distribution profiles of methyl parathion throughout the yarn and fiber structures were similar for all the finishes, lower concentrations of pesticide were observed on the cotton fibers from the starched fabric. Starch reduced the pesticide transferring by rubbing from both 100% cotton and 65% polyester/cotton fabrics. These studies support the intriguing theory that starch can act as a pesticide trap on the fabric surface to decrease pesticide transfer and to enhance pesticide removal. Extensive penetration studies, field studies, and additional investigation of fiber, yarn, and fabric parameters are needed to further quantify the effects of starch.

ABSTRACT:Cotton cellulose was partially carboxymethylated by a one-bath method using monochloroacetic acid and sodium hydroxide. A method was developed to study the extent of the carboxymethylation of cellulose within the cotton fibers using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). Uranyl nitrate was used as a stain. Scanning electron photomicrographs revealed that the carboxymethylation of cellulose occurred throughout the cotton fiber cross section. However, the X-ray microanalysis data indicated a variation in the extent of the reaction among the morphological regions that have different chemical accessibility.

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