Ring-Opening Polymerization of Cyclic Amides Lactams

Ring-Opening Polymerization of Cyclic Amides (Lactams) 

The molecular weight increases with increasing conversion. Regulation of the molecular weight can be achieved by adding small amounts of substances (e.g., benzoic acid) that can react with the polyamide chains by transamidation. Because of the transamidation reaction and hydrolysis of amide bonds, an equilibrium molecular-weight distribution is finally attained (see Sect. 4.1). 

Polymers prepared at 250-270 °C contain an equilibrium concentration of up to 10% of cyclic monomer and partly cyclic higher oligomers after cooling, the monomer and oligomers can be recovered by extraction with water or lower al- 

Aliphatic polyamides of e-caprolactam (Nylon-6) possess great importance as fibers and plastics. 

Polymers made from s-caprolactam in the presence of anionic catalysts at high temperatures have average molecular weights that are initially high but decrease on 

---