The polymerization of vinyl monomers initiated by poly[3-dimethyl-(acryloyloxyethyl)ammonium propane sulfonate], poly(DAAPS), in aqueous solution was studied under vacuum at 85°C. the polymerization proceeds via a radical mechanism without any further initiator. the polymerization is thought to start with the formation of hydrophobic areas with poly(DAAPS) in the aqueous phase. the initiation mechanism involving hydrogen atom transfer is proposed. the effects of the efficiency of grafting, pH, overall activation energy, and the amount of water content and betaine polymer on the polymerization were investigated. A good linear relationship was obtained between the mass of vinyl monomers and the rate of polymerization (Rp) by applying the Michaelis-Menten equation.