FTIR separation of nylon‐6 chain conformations: Clarification of the mesomorphous and γ‐crystalline phases

Publisher Website
Google Scholar
Abstract
Specific infrared absorptions for each form of Nylon‐6 have been indentified. Quenched films were prepared by melt casting and converted in turn to the α‐crystalline and γ‐crystalline structures. The films were examined using Fourier transform infrared spectroscopy (FTIR) with the attenuated total reflection configuration and by X‐ray diffractometry. The FTIR spectrum of the pure mesomorphous component of the quenched film was calculated by subtracting away the contribution of α‐crystalline peaks present due to incomplete quenching. A curve‐fitting procedure was applied to the pure mesomorphous and gamma crystalline spectra. Several peaks in the mesomorphous spectrum are observed to develop a shoulder upon conversion to the γ‐crystalline form. This is due to the extra gauche character imparted to the CN bond between the methylene unit and the amide group. These and other band assignments were confirmed by analysis of model compounds.