Polyazoester has been obtained by the catalyzed polyreaction of azobisbutyronitrile with PEG 400 according to Pinner reaction. The structure and the kinetice of decomposition of the product were researched. The polyazoester was used to initiate radical polymerization of acrylamide limiting the decomposition of the initiator to 37%. By use of the resulting po-lyacrylamide as an emulsifying initiator system stable emulsions of polymers (polyvinylacetate

styrene-ethyl acrylate copolymer) were obtained without additional use of a tenside.