Abstract
We report here the specific features of plasma-induced free radicals of cellulose derivatives such as ethylcellulose (EC) and hydroxyethylcellulose (HEC) on its comparison with those of cellulose. The electron spin resonance (ESR) spectra of Ar plasma-irradiated EC and HEC consist of three kinds of discrete spectral components, two isotropic spectra [doublets (I) and triplets (II), both being assigned to hydroxylalkyl radicals] and one anisotropic spectrum [doublet of doublets (IV) assigned to an acylalkyl radical], and a single broad line spectrum (III). The special feature here is the fact that the spectrum (III) is a major component, contrary to cellulose, which was assigned to an immobilized dangling-bond site (DBS) at the cross-linked region. The results suggest that plasma-induced cross-linking reactions are very predominant in EC and HEC relative to that of cellulose, due to the presence of alkyl substituents in EC and HEC.
