A molecular model for solid‐state polymerization of nylon 6

Abstract

SYNOPSISA theoretical model is developed for the effect of segmental diffusion on reversible step growth polymerization. This model is a n adaptation of the molecular model of Chiu et al. for characterizing the Trommsdorff effect in free-radical polymerization. The model is applied to the specific case of solid-state polymerization of spherical pellets of nylon 6. The results of the simulation are found to show qualitative trends as found by Gaymans et al. experimentally. The parameters of the model are curve fitted to their data using an optimal parameter estimation computer code. It is found that the optimal values of the parameters, which can be independently measured, are quite close to the values reported in the literature. The effect of varying the individual parameters on the progress of polymerization is also studied.

A Review of Modeling of Diffusion Controlled Polymerization Reactions

“…Using the same physical picture as that of CCS the authors [175] finally came to the following equation relating the polycondensation rate coefficient to the diffusivity of the polymer molecules, D and the effective diffusion radius, r m :…”

“…[175][176][177][178][179] Kaushik and Gupta [175] presented a theoretical model for the effect of segmental diffusion on the SSP of Nylon 6. The following kinetic scheme was supposed:…”

Simulation of solid-state polycondensation of nylon-66

“…Satisfactory agreement between theory and experimental data was observed. The sensitivity of the results to the parameters is studied by Gupta [18] with the value of 1 from 10 À1 to 10 À5 , the value of 2 from 2000 to 10.…”

“…For values of W s above 10 À2 mol/kg, however, the results were sensitive to its value. Kaushik and Gupta [18] studied the effect of W s on the SSP process. It was found that the increase of molecular weight is insensitive when the value of W s is below 10 À4 mol/kg.…”

“…The model of the rate constants of the polycondensation reaction associated with diffusional limitation suggested by Achilias and Kiparissides has a relevant role [16,17]. As far as Kaushik and Gupta [18] used the model to simulate the SSP of nylon-6, obtaining good agreement with experimental data, we adopted the rate constants with the same expressions and parameters, which are listed in Tables 3 and 4 respectively.…”