Photopolymerization of Acrylonitrile in Concentrated aqueous solutions of Metal Halides

초록

A photo-induced polymerization of acrylonitrile in the concentrated aqueous solution of metal halides has been investigated. A gel-type hybrid polymer system, consisting of a crosslinked polyacrylonitrile, zinc chloride and water was obtained with a high yield. The rate of polymerization is remarkably increased in the presence of zinc chloride. Actually, no polymer was obtained in the absence of zinc chloride. This implies that zinc chloride plays a dual role in this system, i.e., zinc chloride not only results in the increase in the rate of polymerization but also participates in the photoinitiation process. It was also found that the conversion of pendant nitrile group of the hybrid system to a conjugated ketene-imine structure is accelerated in the presence of zinc chloride. The colorless and transparent system turns to red to black by heating to 100-170C. Furthermore, the hybrid system is highly electric conductive whose order of magnitude reaches 10 Scm. IR spectroscopic study reaveals that the enhancement of vinyl polymerization and the conversion of the nitrile group to ektene-imine structure are ascribed to the complex formation of the nitrile group with zinc chloride.