ESR study of intramolecular energy transfer in the radiolysis of cellulose furoates

✍ Scribed by Sujan Singh; Oscar Hinojosa; Jett C. Arthur Jr.

• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: English
• Weight: 326 KB
• Volume: 14
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1970.070140616

✦ Synopsis

Abstract

The substitution of 2‐furoyl, 5‐methyl‐2‐furoyl, 2‐furanacryloyl, or 5‐bromo‐2‐furoyl groups on fibrous cotton cellulose increased the radiation rsistance of cellulose, as indicated by the retention of strength of the modified fibrous cellulose at high dosages of γ‐radiation compared with that of irradiated, unmodified fibrous cellulose. The presence of electropositive or electronegative substituents on the furan groups did not significantly change their radioprotective effects for cellulose. Electron spin resonance (ESR) spectra of irradiated celluloses indicated that the long‐lived free radical sites were similar, if not the same, in both irradiated, unmodified, and modified celluloses. The radio protective effects of furan groups for cellulose were attributed to absorption of energy from the secondary radiations, primarily the secondary electrons, by the groups due to their π‐electron‐type structures. The absorption of energy by the groups apparently decreased the localization of energy on carbon C~1~ or C~4~ on the cellulose molecule which would result in depolymerization and loss in breaking strength of the fibrous cellulose. The radioprotective effects of furan groups for cellulose were similar to those of benzenoid groups.