13C cross polarization/magic-angle spinning NMR and infrared spectroscopic study of poly(ε-caprolactam) and of poly(ε-caprolactam)/polystyrene blends

Infrared and ¹³C cross polarization/magic-angle spinning nuclear magnetic resonance (¹³C CP/MAS NMR) spectra and T relaxation times of differently treated poly(ε-caprolactam) 1

1 Systematic IUPAC name: poly[imino(1-oxohexamethylene)].

(PCL) and of poly(ε-caprolactam)/polystyrene blends were measured and the fractions of the α- and α-crystalline and mesomorphous PCL forms were determined. The amounts of the α-form obtained from the infrared and ¹³C CP/MAS NMR spectra are in agreement. In the blends, the fraction of the PCL α-crystalline form is higher as compared with extruded pure PCL. The existence of a single T parameter for PCL in each of the samples indicates small dimensions of the crystalline regions; the obtained T values correspond to the PCL phase composition.