Electron spin resonance of irradiated solution‐crystallized polyethylene

If films containing oriented lamellae of solution crystallized polyethylene are rotated in the external magnetic field, marked anisotropy in electron spin resonance is noted. When the magnetic field is perpendicular to the chains the spectrum consists of ten lines with a hyperfine component separation of 15 gauss. When the magnetic field is parallel to the chains, the spectrum is a sextet with a splitting of 34 gauss. These splittings are in fairly good agreement with the studies of McConnell et al. on irradiated malonic acid single crystals. The high resolution and stability of electron spin resonance spectra of irradiated polyethylene crystallized from solution suggest greater perfection of crystalline order than in elongated fibers. Moreover, the results on solution crystallized polyethylene indicate that the alkyl radicals are formed at random in the crystalline matrix.