SYNOPSISGlycidyl methacrylate was graft-copolymerized onto cotton cellulose using both photo-and chemical-initiation techniques using different initiators. The photoinitiators used were uranyl nitrate, ceric ammonium nitrate, and benzoin ethyl ether, whereas the chemical initiators used were ceric ammonium nitrate and potassium persulfate. Optimization of various parameters of grafting, viz., time, temperature, initiator, and monomer concentrations, was carried out. Ceric ammonium nitrate gave the maximum and almost identical values of graft add-on, by both grafting techniques, at equivalent concentration of the monomer. Use of optimized conditions of ceric ammonium nitrate-photoinitiated grafting for sodium hydroxide-swollen substrate as well as for grafting baths incorporating acids enhanced the graft level.

SYNOPSISUV-radiation-induced graft-copolymerization of cotton cellulose was carried out with glycidyl methacrylate (GMA) using ceric ammonium nitrate (CAN) as a photoinitiator as well as a chemical initiator. With increase in the graft add-on, breaking load and moisture regain of cotton decreased, so also its thermal stability. The fiber surface changes due to grafting were ascertained by X-ray diffraction and scanning electron microscopy. 0 1995

SYNOPSISTwo-hydroxyethyl methacrylate was grafted onto cotton cellulose using photoinitiation technique in the presence of the photoinitiator benzoin ethyl ether. Various parameters of the graft-copolymerization reaction, namely time, temperature, initiator, and monomer concentrations, were optimized using the grafting bath containing 10% methanol/acetone to dissolve the photoinitiator. The cotton sample, preswollen in sodium hydroxide, was subjected to grafting under optimized conditions. The preswollen samples showed higher graft add-on values at the equivalent monomer concentration. The moisture regain initially decreased at lower graft add-on levels and increased marginally with higher graft add-on. This behavior of the grafted substrate with respect to moisture regain has been explained.

SYNOPSISThe photoinitiated graft copolymerization of hydroxyethyl methacrylate ( HEMA) onto cotton cellulose was studied using uranyl nitrate (UN) and ceric ammonium nitrate (CAN) photoinitiators. Optimization of various parameters of the graft-copolymerization reaction viz., time, temperature, initiator, and monomer concentration, was carried out. The optimized conditions of grafting were employed to cotton samples swollen in zinc chloride as well as sodium hydroxide. Graft add-on was found to be dependent on the nature of substrate and the concentrations of monomer and photoinitiator. U N was found to be the better photoinitiator, giving higher grafting with HEMA. The grafted samples showed initially decrease and then marginal increase in the moisture regain with increase in graft add-on. The dye uptake of both direct and reactive dyes decreased with increase in graft add-on.

SYNOPSISPhotoinitiated graft copolymerization of the vinyl monomers, styrene and acrylonitrile, onto cotton cellulose was studied using uranyl nitrate and ceric ammonium nitrate as photoinitiators. Uranyl nitrate photoinitiation showed a higher level of grafting for styrene, whereas in the case of acrylonitrile ceric ammonium nitrate was found to be the better photoinitiator. Optimized conditions of grafting, when employed to cotton swollen with sodium hydroxide and zinc chloride, enhanced the graft levels for both monomers. Grafted samples were subjected to thermal analysis, as well as estimation of moisture regain and tenacity. Thermal stability increased, whereas, the moisture regain and tenacity decreased, with the increase in graft add-on in the case of both monomers. Acrylonitrile-grafted cotton showed dyeability with cationic dye that improved with the level of graft add-on. Possible explanations have been given. I NTRO DU CTlO NChemical modification of cotton by grafting reactions with various vinyl monomers provides the potential for significantly altering its physical and mechanical properties. Grafting synthetic polymers onto the cellulosic backbone reduces some of its inherent drawbacks and, in addition, the grafted fiber offers more advantages over those obtained by the physical blending of synthetic fibers with cotton fibers. The low-energy UV radiation process possesses certain advantages like less degradation of the backbone polymer and control over the grafting reaction.Garnett et al.' studied the effect of radiation grafting of styrene onto cellulose in presence of methanol and also in the absence of alcoholic solvents using uranyl nitrate initiator.2 Huang and Chandramouli3 examined structure and properties of cellulose-styrene graft copolymer using ceric ion redox initiation. Similarly, use of inorganic salts has been found to enhance radiation grafting.4 Davis et