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

Electron-nuclear double resonance (ENDOR) spectra were recorded for ra dicals created by irradiation of uniaxially and biaxially oriented sam ples of polycaproamide (PA). The constants of hyperfine interaction (H FI) of uncoupled electron with different protons in macroradical -CO-N H-CH-CH2-CH2- were calculated from the position of line in ENDOR spect ra. It was found that the protons of beta-methylene group are magnetic ally inequivalent and, therefore, the plane of carbonic backbone is tw isted. A deviation of the conformation from ideal trans-zigzag corresp onds to rotation around C(alpha)-C(beta) bond through an angle of 11-d egrees. The principal values of the HFI tensor for alpha-proton and an gular desorientation of the radicals with respect to polymer stretchin g axis are determined. It is supposed that in irradiated PA the radica ls are formed which differ in ste-reoconfiguration of the amide part o f the radical.