||Crosslinking of polysaccharides in room temperature ionic liquids by ionizing radiation
Nagasawa, Naotsugu ,
Shimada, Akihiko田口, 光正
Radiation Physics and Chemistry
134 , 2016-07 , Elsevier Ltd.
Crosslinking of polysaccharides in room temperature ionic liquids (RTILs) by ionizing radiation were investigated by the scavenging method, fluorescent and X-ray photoelectron spectroscopy (XPS) analysis. Radiation chemical yields of hydroxyl radicals inducing the crosslinking of cellulose were estimated with phenol as a scavenger, and increased with water content in 1-ethyl-3-methylimidazolium acetate (EMI-acetate). Cellulose gel was also produced in fluorescent carboxylate-based RTILs,1,3-dibutylimidazolium acetate (DBI-acetate). Light emission from DBI-acetate in cellulose gel was observed and 20-nm redshifted at a maximum wavelength of 415 nm when excited at 323nm. Expected elements of carbon and oxygen were detected in neat cellulose by XPS,while additional nitrogen was detected in radiation-crosslinked cellulose gel produced in EMI-acetate. These results indicate that RTILs is incorporated in thecellulose gel. Chitin gel was first obtained in 1-butyl-3-methyimidazolium chloride by γ-ray irradiations,and its gel fraction increased with the dose and reached 86% at 60 kGy.