Saturation ESR spectroscopy of PA12 polyamide

This work presents the results of our EPR study of polyamide 12 (PA12) –[NH–(CH2)11–CO]n–NH–(CH2)11–CO–. In this study the spin probe method with “conventional” or “continuous saturation” at low temperatures (4–260 K) was used. The aim of our investigation was to determine if it possible to obtain the saturation effects and establish experimental conditions by using commercial ESR spectrometers. We also wanted to know what information about the relaxation processes in polymeric materials could be obtained. We have found that the information about the relaxation processes (below frequency ≈104 Hz) at low-temperatures in polymers could be obtained. The process, which could be associated with mobility of the spin probe is probably connected with the process called γ (in PA12 as yet unrecorded by using others methods). This process in other systems is usually connected with mobility of the methylene sequences and could be used to study the amorphous regions of PA12.