ESR studies of photoirradiated cellulose on radical formation and decay

摘要

AbstractThe ESR spectra of untreated samples and photosensitized samples of rayon cellulose, amorphous cellulose, and wood cellulose irradiated with ultraviolet light were studied. Generally, several kinds of spectra were established, and ferric ion photosensitizer increased the yield of free radicals in celluloses on irradiation. The observed five‐line spectrum was resolved to be a superposition of single‐line, two‐line, and three‐line spectra. The decay of free radicals of celluloses at ambient temperature was also examined for changes of the pattern and the intensities of ESR spectra. Based on the changes of spectra induced by a warm‐up process, three kinds of radicals which gave three components of the five‐line spectrum were identified. During the warm‐up process, phenomena of radical migration and formation of new radicals synchronized with the decay of radicals were recognized on photosensitized samples of rayon cellulose and amorph