Dynamic nuclear polarization of electron-beam irradiated polyethylene by pairs of alkyl free radicals

電子線照射したポリエチレン試料に特有のラジカルペアによる動的核偏極

熊田 高之   

Kumada, Takayuki

We compared dynamic nuclear polarization (DNP) behavior of electron-beam (EB) irradiated polyethylene (e-PE) with that of TEMPO-doped polystyrene (T-PS). Growth and decay rates of proton polarization PH of e-PE increase linearly with increasing concentration Ce of free radicals, whereas those of T-PS increase with square of Ce. From these results, we suggest that the pair of alkyl radicals produced by the radiolysis and the subsequent hydrogen abstraction reaction in e-PE plays an important role on DNP, whereas T-PS is polarized by a pair of unspecified TEMPO radicals accidentally located nearby.