SYNOPSISGraft copolymerization of acrylamide on cotton (dialdelyde cellulose, DAC) fibers and fabrics was studied in a limited aqueous system using K,Sz08 as the initiator. Grafting parameters under different sets of conditions were determined and the mechanism of graft copolymerization discussed. Optimum conditions for grafting were established and the effect of polyacrylamide grafting on tenacity, modulus, breaking elongation, and stiffness of the cotton (DAC) fabrics and on their dyeability and moisture regain properties were also studied; 9-10% grafting of polyacrylamide on (DAC) fabric at pH 7-10 imparts an improved balance in its mechanical and other properties. 0 1995 John Wiley & Sons, Inc.
I NTRO D U CTl ONReports on graft copolymerization of acrylic monomer such as acrylonitrile, methyl acrylate, and methyl methacrylate are widely available in the literature.'+ Grafting in such cases renders cellulose fibers and fabrics somewhat less hygroscopic or hydrophilic in view of the hydrophobic nature of the relevant grafted-on acrylic polymers. Acrylamide monomer giving a hydrophilic polymer has drawn limited attention for studies in graft copolymerization on cellulose. Likewise, vinyl grafting on oxycellulose has also been studied5-' scantily. It is in this background that studies of graft copolymerization of acrylamide on cotton cellulose fibers and fabrics of a controlled, low degree of oxidation were undertaken and relevant results are reported in this paper.
EXPERIMENTAL
Materials
Cotton CelluloseMill cleaned S-4 quality cotton fiber and a plain weave cotton (poplin) fabric (having an average of * To whom correspondence should be addressed.
Monomer and Other ChemicalsAR-grade acrylamide ( AAm) (monomer), potassium persulfate (initiator), and sodium metaperiodate ( reagent for oxidation of cotton cellulose)were obtained from E. Merck.
ABSTRACT:The role of persulfate-induced graft copolymerization of mixtures of acrylamide and methyl methacrylate at 50ЊC in modifying mechanical properties of jute fibers of different compositions was studied in a limited aqueous system following a pretreatment technique. Results obtained indicate that such a process admits a good scope for modification of mechanical properties of jute fiber depending on degree of grafting achieved and compositional variations of (1) the feed monomer mixture and (2) the multiconstituent jute itself, consequent to selective removal of lignin and hemicellulose to different extents from the fiber. Low to moderate removal of hemicellulose is more effective than a similar degree of removal of lignin from jute in rendering the fiber more amenable to vinyl grafting using the mixed monomer system without being adversely affected with respect to tensile properties.
SYNOPSISAcid catalyzed grafting, polycondensation, and crosslinking of acrylamide-formaldehyde (AMF) resin and simultaneous free radical graft copolymerization of the resin moieties on jute fabric were studied using a combination of MgCl 2 and K 2 S 2 O 8 , respectively, as the (dual) catalyst system. Resin application and finish on jute fabric were accomplished by padding at room temperature, drying at 80ЊC, and polymerization and curing at 150ЊC. Changes in chemical structure and surface morphology of jute fiber on resin treatment were examined by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), respectively. Application of 8% AMF resin under the dual catalyst system in appropriate doses produced the most improved balance in the properties of jute fabric, including tenacity, modulus, breaking extension, stiffness, crease recovery angle, fiber shedding, moisture regain, and dyeability. Analysis indicated that all the major constituents of jute, namely, acellulose, hemicellulose, and lignin reacted with the AMF resin system and that the resin finish turned jute thermally more stable. Effects of different degrees of removal of lignin and hemicellulose from jute on its AMF resin uptake were also studied and reported.
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