Deconvolution of the excess heat capacity of the Brill transition in nylon 66

The Brill transition in nylon 66, crystallized from solution, is a small, diffuse endotherm extending between roughly 130-230 deg C. The excess heat capacity in this region has been deconvoluted using established methods of statistical mechanics. As have been found for the unfolding transitions in several globular proteins, the data can be characterized by a model having two energy states within 5% of their fractions. The transition appears to involve a mass corresponding to approx 25 chemical repeat units or about five stems in a folded-chain crystal. This is much smaller than the size of the crystals calculated from small- and wide-angle X-ray data. Spectra, graphs. 9 ref.--AA