Conformations and 13C NMR chemical shifts of some polyamides in the solid state as studied by high‐resolution 13C NMR spectroscopy

High-resolution 13Carbon nuclear magnetic resonance (NMR) spectra of Nylons 4, 6, and 66 in the solid state were measured over a wide range of temperature. From the results, it was found that resonance lines of crystalline and noncrystalline components were separable and their chemical shifts were determined. The 13C chemical shift behavior is closely related to their conformation. The origin of the conformational effects on the chemical shifts is discussed.