The xanthate method of grafting. II. Effect of operating conditions on the grafting of acrylonitrile onto Wood pulp

Abstract

Wood pulp was copolymerized with acrylonitrile as a monomer using the xanthate grafting method. This method takes advantage of the capability of cellulose xanthates to form a redox couple with a suitable oxidation agent. The present work uses the degree of xanthation γ ≐ 5 and hydrogen peroxide as an oxidant. Experiments carried out under different conditions have permitted to evaluate the influence of various reaction parameters on the graft copolymerization. Among the factors investigated, two appeared to be a paramount importance: the initial pH of the reaction mixture and the concentration of hydrogen peroxide. A change in one of these two parameters produced profound effects on the total conversion to polymer as well as on the copolymer:- homopolymer ratio. By a suitable combination of initial pH and peroxide concentration, it was possible to synthesize graft copolymers whose homopolymer content approaches zero.