Reaction Kinetics and Simulation for the Solid‐State Polycondensation of Nylon 6

A comprehensive model for the solid‐state polymerization (SSP) of nylon 6 has been developed. With regard to the reactive end‐to‐end distance distribution, for the well‐stirred system in which there is a homogeneous distribution, the whole process of SSP has been divided into two stages in this model. The polymer crystalline fraction is modeled as containing only repeat units, thus concentrating end groups, condensate and monomers in the amorphous fraction. Many effects neglected by previous models are considered, such as variable crystallinity, the effect of leaching and end‐to‐end distance distribution. A more practical technique has been used to generate the initial values used for simulation, which were then used to obtain the optimal parameter values. Detailed quantitative results were obtained to study the effects of changing the important operating conditions on SSP, such as intermediate remelting of nylon 6 pellets and leaching of monomer and water before SSP.