γ‐radiolysis of acetylated cotton cellulose: An ESR study

Chidambareswaran, P. K.; Sundaram, V. S.; Singh, B. B.

doi:10.1002/pol.1972.150100912

Cited by 8 publications

(1 citation statement)

References 14 publications

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“…According to Arthur et al [46], a single-line spectrum can also result from homolytic C-H bond cleavage at C(1) or C(4). Anyway, a quartet of hyperfine splitting constants of about 13 ± 1 G and a g value of 2.0044 ± 0.0004 due to the interaction of an unpaired electron with three hydrogen atoms have also been found [52]. Our results from the ESR spectra of plasma-treated cotton confirm much of the previous evidence concerning the number and position of the four most abundant free radicals generated by plasma treatment.…”

Section: Esr Investigation On the Persistent Free Radical Sites Of Plsupporting

confidence: 87%

Free radical generation upon plasma treatment of cotton fibers and their initiation efficiency in surface-graft polymerization

Andreozzi

Castelvetro

Ciardelli

et al. 2005

Journal of Colloid and Interface Science

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Section: Esr Investigation On the Persistent Free Radical Sites Of Plsupporting

confidence: 87%

Free radical generation upon plasma treatment of cotton fibers and their initiation efficiency in surface-graft polymerization

Andreozzi

Castelvetro

Ciardelli

et al. 2005

Journal of Colloid and Interface Science

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Studies on the radiolytic degradation of cellulose acetate membranes

Ramachandhran

Misra

1985

J of Applied Polymer Sci

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SynopsisThe effect of y-irradiation on the performance of wet cellulose acetate membranes in the dose range of 2.5-10 Mrads was investigated using a 6oco source. Changes in transport prop erties and inherent viscosity of the membranes suggested continued degradation as a result of irradiation. Solubility and specific gravity changes accompanying irradiation indicated some sort of structural aggregation occuring at higher doses. Consumption of dissolved oxygen during irradiation and the extent of deacetylation of the membrane polymer were determined to study the kinetics of the degradative process. Analysis of the end products of irradiation was attempted by UV spectroscopy. ESR spectra of membrane polymer after irradiation were analyzed to identify the free radicals generated. A tentative mechanism of radiolytic degradation causing the observed performance failure is proposed.

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Photodegradation of cellulose acetate fibers

Hon

1977

J. Polym. Sci. Polym. Chem. Ed.

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The photodegradation of cellulose acetate fibers by ultraviolet light in vacuo at 77°K and at ambient temperature was studied. Three kinds of light sources with different wavelengths between 2353 and 6000 Å were employed. ESR studies at 77°K show that several kinds of free radicals are produced from cellulose diacetate (CDA) and cellulose triacetate (CTA) fibers when irradiated with light of wavelength shorter than 2800 Å. Among these methyl radicals formed decayed within 210 min at 77°K. When the temperature was raised above 77°K, radical transformation occurred at 87°K and most of the free radicals decayed at 193°K, whereas the cellulosic radicals were stable at this and even at higher temperatures. Ultraviolet spectroscopy studies revealed that the main chromophores are the carbonyl function of the acetyl group and acetal groups in the polymer. The photodegradation of the polymers at ambient temperature resulted in the formation of gaseous products (mainly CO, CO2, and CH4), together with the loss of bound acetic acid content and sample weight. Decreases in viscosity and reduction of tensile strength and elongation were also observed in the irradiated samples, revealing that the overt effects of ultraviolet light on cellulose acetate fibers are interpreted in terms of free‐radical reactions ultimately leading to main‐chain and side‐group scissions, unsaturation, and the formation of small molecule fragments. Among these, main‐chain scission took place predominantly in CDA fiber and side‐group scission in CTA fiber. The mechanism of the fundamental photochemical degradation processes of cellulose acetate fibers is elucidated.

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γ‐radiolysis of acetylated cotton cellulose: An ESR study

Cited by 8 publications

References 14 publications

Free radical generation upon plasma treatment of cotton fibers and their initiation efficiency in surface-graft polymerization

Free radical generation upon plasma treatment of cotton fibers and their initiation efficiency in surface-graft polymerization

Studies on the radiolytic degradation of cellulose acetate membranes

Photodegradation of cellulose acetate fibers

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