Polymerization of lactams. 98: Influence of water on the non-activated polymerization of ε-caprolactam

The sensitivity of so-called non-activated polymerization of ε-caprolactam to the presence of water in the polymerization mixture has been studied. Polymerizations were initiated with 1 mol% sodium salt of ε-caprolactam, magnesium di(ε-caprolactamate) and/or ε-caprolactam magnesium bromide and were carried out at water concentration 0–1 mol% and in the temperature range of 190–230 °C. The influence of water content in the polymerization mixture on the polymerization rate and polymerization degree was evaluated. The studied initiators exhibited different sensitivity to the water added in the polymerization mixture and the role of water in the course of anionic polymerization of ε-caprolactam is discussed. Magnesium initiators are exceptional, they are capable to eliminate retardation effect of water on studied polymerization.