Rayon fibers were metallated with Li, Na and K methoxides in pure methanol or a mixed solvent consisting of CH
3OH and dimethyl sulfoxide (DMSO) (1:1v/v) and the metallated fibers were allowed to react with acrylamide (AAm) in various solvents by the anionic mechanism to give graft copolymer with poly-β-alanine branches as well as polyacrylamide branches.
Effects of a swelling pretreatment in water or DMSO, Na metallation time and medium, and methoxide concentration upon the degree of the metallation were investigated. The degree of Na metallation increased with CH
3ONa concentration for the water- or DMSO-swollen rayon and the degree of metallation was higher for the latter. The higher degree of Na metallation was obtained on the exchange reaction with CH
3ONa in the mixed solvent (1:1 CH
3OH•DMSO) than in pure methanol at lower concentration of CH
3ONa, and the degree of Na metallation of the DMSO-swollen rayon increased with the DMSO content in the mixed solvent.
Effects of the AAm concentration, degree of metallation and reaction temperature upon the total graft-on and the graft-on via transition polymerization were investigated in various solvents. The total graft-on increased with the AAm concentration in the reaction solution for the Na metallated rayon. The graft-on via transition polymerization which was determined by the analysis of prim. amide nitrogen increased with the AAm concentration and was 8_??_34% of total graft-on. The graft-on was scarcely influenced by the addition of an inhibitor of radical polymerization into the reaction solution. Apparent activation energies of the graft-polymerization were 8_??_11kcal/mol for the Na metallated rayon fibers treated in various solvents. Both curves of the total graft-on and the graft-on via transition polymerization vs. the degree of metallation with Li, Na and K had maxima at 0.22_??_0.32mol/AGU (AGU: glucose unit) and their maximum values increased with an increase in the degree of swelling of the preswollen rayon, with a decrease in the dielectric constant of the solvent in the reaction solution and with an increase in the electropositivity of the alkali metal used.
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