synopsisEthyl acrylate was graft-copolymerized from acetonewater systems with 7-irradiated, purified cotton cellulose. The scavenging of the free radicals in the irradiated cellulose by water, acetone, and water-acetone systems was determined by electron spin resonance spectroscopy. The ESR spectra of free radicals, scavenged by water and acetone, were recorded by the use of a time-averaging computer attached to the ESR spectrometer, in which the ESR spectrum of the irradiated cellulose, which had been immersed in water and/or acetone, was electronically subtracted from the ESR speotrum of the irradiated cellulose control. For both water and acetone, the ESR spectra of the scavenged free radicals were singlets. This indicated that free radical sites formed on carbon C , or C, on radiation-initiated depolymerization, which would generate singlet ESR spectra, were readily accessible to these solvents. The maximum scavenging of the radicals was obsemed when irradiated cellulose was immersed in acetone-water solution which had a composition of 25/75 vol-'%. The scavenging of the free radicals in irradiated cellulose when immersed in acetone-water solutions was less than when immersed in methanol-water solutions. Also, the extent of graft copolymerization of ethyl acrylate from acetone solutions with irradiated cellulose was less than that of ethyl acrylate from methanol solutions. These differences were probably due to differences in the diffusion rates of acetone and methanol into the cellulosic structure. The Trommsdorff-type effect in the acetone solutions would be less than in the methanol solut,ions, since aret,one is a better solvent for poly(ethy1 acrylate) than methanol.