Investigations on nylon 4 membranes. Synthesis and transport properties. I. Synthesis of nylon 4 polymer

Abstract The synthesis of nylon 4 (polypyrrolidone) by the anionic polymerization of 2‐pyrrolidone through the use of the CO 2 /potassium pyrrolidonate catalyst system for use in preparing polymer membranes for separation purposes was investigated in detail. The effects of the quantity of CO 2 , the potassium pyrrolidonate catalyst, and the reaction temperature on the yield and molecular weights of the nylon 4 were studied. At reaction temperatures of 50°C and a reaction time of 120 hr, a yield of 50.9% with intrinsic viscosity of 4.42 (corresponding to M n of 108,200 and M w of 135,850) was obtained. The molecular weight distributions of the nylon 4 were determined by gel permeation chromatography (GPC) using m ‐cresol as the eluting solvent and were found to have a relatively narrow distribution.