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

The synthesis of nylon 4 (polypyrrolidone) by the anionic polymerization of 2‐pyrrolidone through the use of the CO2/potassium pyrrolidonate catalyst system for use in preparing polymer membranes for separation purposes was investigated in detail. The effects of the quantity of CO2, 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 Mn of 108,200 and Mw 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. Copyright © 1981 John Wiley & Sons, Inc.