Study on the Molecular Mobility in the Polyamide/SrFeO Composites by In Situ Infrared Spectroscopy

Polyamide 6(PA6) and its composite with strontium ferrite (SrFeO) magnetic powders at different concentration levels (33%, 80%) are in situ investigated by temperature-dependent Fourier transform infrared spectroscopy (FT-IR). It is found that the intensity changes of the “free” (nonhydrogen bonded) N?H stretching vibration as a function of temperature can be used to determine the glass transition (T _g) and melting temperature (T _m); whereas the hydrogen-bonded N?H stretching vibration is only sensitive to T _m. Our results reveal that high SrFeO contents increase the T _g and T _m of PA6. These observations suggest that the molecular chains of PA6 are confined with increasing content of SrFeO.