Ring‐opening polymerization of cyclic compounds with bifunctional groups. Part II. Polymerization of a lactam thioether and lactarn sulfone

Abstract

Abstract 7‐Membered lactam thioether and lactam sulfone which contain amide and thioether or sulfone groups within the ring have been synthesized and polymerized in the presence of various catalysts. Phosphoric acid was the most effective catalyst for the polymerization of the lactam thioether but the lactam sulfone did not polymerize owing to thermal decomposition. The resulting polyamide thioether had a mp of 180 to 185°C which was much higher than that of the polymer from the lactam ether of the same 7‐membered ring. The polymerizability of the lactam thioether was higher than that of ε‐caprolactam and it was found that the reactivity of the amide group is influenced by the thioether group within the ring.