Radiation-induced solid-state polymerization in binary systems. VIII. Polymerization and foaming of multicomponent systems including acrylamide and acrylic acid

Abstract

Radiation-induced polymerization and foaming of multicomponent systems including acrylamide, acrylic acid, and foaming agents were studied. Eutectic mixtures such as acrylamide–itaconic acid were polymerized in solid state and then foamed by heating at 130 ∼ 200°C. The solution systems such as acrylamide–itaconic acid–water and acrylamide–maleic anhydride–urea–water were polymerized in liquid and supercooled phases at higher rates and foamed to a higher degree of expansion. Foams of poly(acrylic acid) and poly(methacrylic acid) were obtained by polymerization and heating of acrylic acid (methacrylic acid)–urea–water systems. It was deduced that the nonmelting or flowing property of these acrylic polymers, especially the semithermosetting property of polyacrylamide, had an important effect on the foaming mechanism.