On the behavior of organophosphorus lactam derivatives during anionic polymerization of ε‐caprolactam

Abstract This article deals with the anionic polymerization of ε‐caprolactam in the presence of N‐substituted phosphorus‐containing derivatives of ε‐caprolactam: diethyl‐(N‐caprolactam)‐phosphonite (PL1); diethyl‐(N‐caprolactam)‐phosphonate (PL2), and 2,5‐dichlorophenyl‐bis‐(N‐caprolactam)‐phosphinate (PL3). It has been found out that PL1 and PL3 had an accelerating effect on the anionic polymerization of ε‐caprolactam. The polymerization runs at high velocity and high degree of conversion. PL2 does not accelerate the anionic polymerization of ε‐caprolactam, but when the polymerization is activated by a strong activator of acyl lactam type, and the PL2 concentration is commensurate with that of the activator, the process runs at a slightly lower rate and at a relatively high degree of conversion. The kinetics of the anionic polymerization in the presence of the three compounds was investigated. Equations describing the effect of the reagents on the polymerization rate were suggested. The activating energy of the polymerization was found out. The different actions of PL1, PL2, and PL3 during the anionic polymerization of ε‐caprolactam were explained by their structural differences.