Co(III) Acetylacetonate-Complex-Initiated Grafting of N-Vinyl Pyrrolidone on Cellulose in Aqueous Media

摘要

The graft copolymerization of N-vinyl pyrrolidone (N-VP) onto cellulose was carried out with a cobalt acetylacetonate complex Co(acac)_3 as an initiator under a nitrogen atmosphere at 50 +-0.1degC. The graft yield percentage (%G) obtained as a function of the concentrations of N- VP and Co(acac)_3 and the temperature was used to calculate various other grafting parameters and the grafting rate dependence on the concentrations of monomer, Co(acac):1 and reaction temperature. The energy of activation (#DELTA#E_a) for the grafting of N-VP onto cellulose was 22.7 kJ/mol within 40-60degC. The molecular weights of the grafted chains and homopolymers were determined visco- metrically with a Ubbelohde-type viscometer. Graft yield (%G) in the presence of various additives such as sodium lauryl sulfate, cetyltrimethylammonium bromide, and methanol was studied, and the results are suitably explained. On the basis of the experimental results, a reaction scheme for graft copolymerization is proposed, and a kinetic rate expression is presented.