SYNTHESIS OF HIGH-MOLECULAR-WEIGHT NYLON-6 BY ANIONIC-POLYMERIZATION OF EPSILON-CAPROLACTAM - MECHANISM AND KINETICS

Studies on the mechanism and kinetics of the anionic polymerization of epsilon-caprolactam were carried out by observing the kinetic data. T he kinetic data were obtained as the functions of the concentrations o f the catalyst and chain initiator. The rate equation of the polymeriz ation was derived as follows, -d[M]/dt=k[I][C] ([C]less than or equal to 1.5x[I]) and -d[M]/dt=k'[I](2) ([C]>1.5x[I]). Here, [M], [I], and [ C] are the concentrations of monomer, chain initiator, and catalyst, r espectively. This suggests that the reaction between lactam-anion and polymer chain end (acyl-lactam) is the rate-determining step of the po lymerization. The intermediate route of the rate-determining reaction is likely the pathway where the protonation occurs on the oxygen atom (at the initial stage of the reaction) and ring-opening follows. The v alues of apparent activation energy for the polymerization were 19.0 k calmol(-1) ([C]less than or equal to 1.5x[I]) and 20.7 kcalmol(-1) ([C ]>1.5x[I]), respectively.