simulation of solid-state polycondensation of nylon-66<fnr href="fn1"></fnr> <fn id="fn1"> this paper was presented at the 2nd international symposium on hi-tech polymers and polymeric complexes (hppc-ii), zhengzhou university, china on 13–19 september 1999.</fn>

A new model of solid-state polymerization of nylon-6,6 has been developed. The polymer crystalline fraction is assumed to consist of only repeat units, leaving end-groups and condensate in the amorphous fraction. Many effects neglected by previous models are considered, such as variable crystallinity, initial moisture and starting molecular weight. This model is compared to experimental data with good agreements. Differential scanning calorimetry graphs show that the crystalline structure phase tends to be increasingly perfect during heat treatment, indicative of the premelting temperature drawing near the melting point up to 14 °C after solid-state polycondensation with little change of melting point. Copyright © 2000 John Wiley & Sons, Ltd.