Research For New Controlled Living Radical Polymerization

As so far, polyarcylamide(PAM), a kind of water-soluble polymer widely used in water-treatment, oil exploitation, etc, is only synthesized by conventional radical polymerization. While the molecular weight and the disperisty are not well-defined, generally. In this article, atom transfer radical polymerization(ATRP), a novel controlled radical polymerization(CRP), is applied to synthesize polyacrylamide with narrow polydispersity. The exploration employed CuCl as catalysts, 2,2-dipyridine as ligands, benzyl chloride or 2-chloride propionamide as initiators, water as media. Varying the reaction condition and composition, the reaction kinetics is mainly involved.It is identified that polyacrylamide with low polydispersity(≤1.5) can be synthesized by infra-red absorption spectroscopy and gel permeation chromatography. Meanwhile, changing the temperature, monomer concentration, ratio of catalyst to initiator concentration and ratio of monomer to initiator concentration, the kinetics is analyzed. It is shown that the first-order kinetics plot for the disappearance of the monomer is linear. The plot of conversion versus number average molecular weight is linear. And the polydispersity indexes decrease with the increasing conversion. It suggests that the reaction carried out by the principle of ATRP. The reaction rate and average molecular weight can be improved at higher temperature. Higher monomer concentration will enhance rate and average molecular weights, however, the fitting ratio of monomer to initiator concentration greatly influence the reaction. The ratio of catalyst to initiator concentration will improve the rate, however, it do not increase of molecular weight, obviously. The better ATRP of acrylamide is investigated with 2-chloride propionamide instead of benzyl chloride as initiators.