The cyclic initiating system of Ce4+ - Ce3+ - Ce4+

in which the product of reduced ion Ce3+ forming from Ce4+ after initation being oxidized again to the original oxidizing ion Ce4+ is examined. The characters of process of the graft copolymerisation using the cyclic initiating system is compared with the ones using ceric and persulphate individually. When using the cyclic systerm as initator

it was more effective to graft polymerise acylamide onto starch and a rather high proportion of graft copolymer was made as opposed to using persulphate individually.