Radiation-induced solid-state polymerization in binary systems. IX. Polymerization and foaming of multicomponent systems including inorganic acid and acrylic monomers

It was found that binary systems consisting of inorganic acid and organic amide or nitrile form a stable glassy phase owing to the large molecular interaction between the components. The change in Tg values with change in composition of these binary systems was studied. Gamma ray-induced polymerization of inorganic acid and acrylamide or acrylonitrile systems was carried out in a supercooled phase. The polymerization rates in acrylamide–inorganic acid systems had a maximum at a temperature Tv (30°–50°C higher than the glass transition temperature), but in acrylonitrile–inorganic acids systems there was no maximum rate at any temperature. Foaming occurred during irradiation in the polymerization of acrylamide–urea–sulfuric acid system. The insource foaming was attributed to the promoting effect of sulfuric acid for the decomposition of urea and the heat accumulation by the acceleration of the polymerization.