Dispersion polymerization of acrylamide with water-soluble chitosan as the stabilizer

Abstract

A cationic polyelectrolyte of P (CMTC-AM-DMC) was synthesized by dispersion polymerization in aqueous solution of ammonium chloride, with acrylamide and dimethylaminoethyl methacrylate methyl chloride as main raw materials. N-carboxymethylthioureidochitosan was used as both the reactant and the stabilizer, and 2,2'-azobis (2-amidinopropane) dihydrochloride (V-50) as the initiator. The effects of the major reaction variables such as the concentration of inorganic salt and initiator, temperature, reaction time, and pH on the polymerization were discussed in this article. The optimal conditions of the polymerization were determined by orthogonal tests. The results showed that an increase in salt concentration resulted in an increase of molecular weight and particle size and a decrease of apparent viscosity, while when salt concentration was up to 23.9%, apparent viscosity was slightly higher than others. Molecular weight, particle size, and apparent viscosity all decreased with the increase of initiator. The apparent viscosity, molecular weight, and particle size would decrease with pH, and the product would be coagulated when pH > 7. Temperature influenced the characteristic a lot. Overall conversion was less dependent on these factors except for the temperature. Molecular weight and overall conversion increased gradually with the time, and the monomers could react completely at about 5-7 h. Flocculation occurred with 13% of salt concentration, 0.005% of initiator, and pH > 7. The optimal reaction conditions for obtaining a stable aqueous dispersion were 22.3% for ammonium chloride, 0.007% for initiator, react under 55 °C for 5 h at pH = 4. © 2012 Wiley Periodicals, Inc.