ELECTRON-NUCLEAR DOUBLE-RESONANCE SPECTRA OF MACRORADICALS IN IRRADIATED POLYCAPROAMIDE

Electron-nuclear double resonance (ENDOR) spectra were recorded for radicals created by irradiation of uniaxially and biaxially oriented samples of polycaproamide (PA). The constants of hyperfine interaction (HFI) of uncoupled electron with different protons in macroradical -CO-NH-CH-CH2-CH2- were calculated from the position of line in ENDOR spectra. It was found that the protons of beta-methylene group are magnetically inequivalent and, therefore, the plane of carbonic backbone is twisted. A deviation of the conformation from ideal trans-zigzag corresponds to rotation around C(alpha)-C(beta) bond through an angle of 11-degrees. The principal values of the HFI tensor for alpha-proton and angular desorientation of the radicals with respect to polymer stretching axis are determined. It is supposed that in irradiated PA the radicals are formed which differ in ste-reoconfiguration of the amide part of the radical.