When the polymerization of vinyl acetate or acrylonitrile is initiated by persulphate in the presence of cellophane, grafting onto the cellulosic baclcbone occurs. This is proved by comparing the graft with a physical mixture of cellulose and homopolymer.Sotne aspects of the mechanism of this grafting are studied by means of model cornpou~lds, in particular pinacol. I t is found that the rate of polymerization of acrylonitrile initiated b y persulphate is increased by the addition of pinacol, but decreases on addition of more pinacol. This may be explained by assuming that the radicals formed from the pinacol can terminate each other and that this reaction competes with the reaction between these radicals and the monomer. The amount of acetone formed by the persulphate oxidation of pinacol a t low pinacol concentrations is about 0.5 nlole per mole persulphate and decreases with increasing pinacol concentration. This indicates complexities that do not exist in the ceric ion oxidation of pinacol.