Computer experiments on crystalline nylons:: structural analysis of nylons with large aliphatic segments

A theoretical study based on force-field calculations has been performed to investigate the structural preferences of crystalline even nylons n with large and very large aliphatic segments. Atomistic energy calculations and Monte Carlo simulations were carried out considering the conventional alpha and gamma forms of nylons 10, 12, 18, 24, and 32. Results indicated that the gamma form is the most favored for nylons 10, 12, 18, and 24. However, the gamma structure was unstable for nylon 32, a polymer in which the density of hydrogen bonds is almost negligible. In this case, the alpha arrangement is energetically more favored than the gamma one.