In this study, ceric salt-and g-ray-initiated graftings were used in comparison with photografting because both are a typical initiation system for chemically initi-In a previous article, 1 photografting was applied to ated and radiation-initiated graftings on cellulosic mafunctionalize cellulose and its derivatives; that is, terials, respectively. Thus, water-absorbing function of highly water-absorbing cellulosic materials were syn-AA-and MAA-grafted CMC samples prepared by photo-, thesized by photografting of acrylic acid (AA) on ficeric salt-, and radiation-initiated systems was comberous carboxymethyl cellulose [CMC; degree of substipared to understand the characteristics of photografttution (DS) ร
0.1-0.4) in the presence of N,N-methyling for the functionalization of cellulose and its derivaenebisacrylamide (MBAAm) as a crosslinker. This artitives. cle deals with the effect of grafting initiation system on water-absorbing characteristics of AA-and methacrylic acid (MAA)-grafted CMC samples.
Various grafting techniques can be utilized for syn-EXPERIMENTAL thesizing cellulosic absorbents for water. Williams and Stannett 2 synthesized highly water-absorptive cellu-Materials lose by postdecrystallization of AA-grafted cellulose, which was prepared by preirradiation method. Vitta et Dissolving pulp from softwoods was used as a cellulose al. 3 studied the water and saline retention values of sample. Fiberous CMC (DS ร
0.1-0.2) was prepared AA-and MAA-grafted celluloses prepared by ceric saltby reaction of the cellulose sample with chloroacetic initiation method and obtained the water absorbency, acid according to the ordinary method. 8 MBAAm and up to 40 g/g, after suitable posttreatment. Sakata et ceric ammonium nitrate (Ce 4/ ) were all of reagent al. [4][5][6] reported that the partially hydrolyzed graft copolygrade and used without further purification. AA, MAA, ymers of crosslinked polyacrylamide on cellulose and and methyl methacrylate (MMA) were purified by disits derivatives synthesized by using ceric salt-initiation tillation under reduced pressure. method can absorb more water than other absorbents from starchy and synthesic polymers do. Lepoutre et al. 7 studied cellulosic absorbent for water prepared by Grafting grafting of acrylonitrile on cellulose, followed by posthydrolysis, and reported that water absorbency of the absorbent is independent of the grafting initiation sys-Photografting (photo system) was carried out in a tems, such as ceric salt, cellulose xanthate-hydrogen Pyrex TM glass tube containing 0.40 g CMC peroxide peroxide, and ferrous ion-hydrogen peroxide. and 40 mL water, in which 0.015M monomer and a known quantity of MBAAm were dissolved, at 30ะC under nitrogen atmosphere. The CMC peroxides with per-