Effects of Gamma, High-Energy Electron, and Thermal Neutron Radiations on the Fibrillar Structure of Cotton Fibers

Abstract

Changes in the structure of cotton fibers after expesure to gamma, high-energy electron, and thermal neutron radiations, in various ambient atmospheres, were evaluated by the techniques of optical and electron microscopy. Radiation exposures evaluated were: gamma rays, 10 5 to 4 × 10 8 r.; 2-Mev electrons, 5 × 10 4 to 10 8 rep; integrated thermal neutron fluxes, 5 × 10 14 to 10 17 nvt. Changes in the physical and chemical properties of similarly irradiated fibers have been, or are to be, reported in other publications. All irradiated, unmodified cottons could be differentiated from unexposed cottons by optical microscopical observations of samples stained in Nile Blue Sulfate. Gamma ray and electron exposed samples differed from unexposed fibers. in swelling behavior in 0.2 M ( in Cu) cupriethylenediamine hydroxide, but thermal-neutron-irradiated cotton differed from the control only after exposure to an integrated flux of 10 17 nvt.Electron micrographs of the fibrillation patterns exhibited by fibers exposed to gamma and electron radiation doses of 5 X 10 6 to 10 8 r. or rep on beating in water in a Waring Blender showed the formation of increasingly smaller fragments of samples. Some shortening of fibrils and an increase in number of broken ends of microfibrils were seen in neutron-irradiated cotton exposed to 10" nvt; at lower integrated neutron fluxes, fibrillation was unchanged. No distinct differences were found in microscopical tests between gamma and electron irradiated fibers or between gamma-exposed fibers irradiated in oxygen and nitrogen. At doses of 4 × 10" r. of gamma rays, the trend toward smaller fragments reversed and short chunks of material were observed.Varying amounts of degradation were observed in modified cottons after irradiation. Smaller fragments were observed in cottons modified to change and reduce the total crystalline cellulose; the fibrillation of acrylonitrile-treated cotton appeared unchanged, but irradiation produced a decrease in the size of fragments of dichloropropanol-and dimethylol cyclic ethyleneurea-modified samples.

Potential effects of ionizing radiation on the evidentiary value of DNA, latent fingerprints, hair, and fibers: A comprehensive review and new results

“…Molecular degradation is further supported by reports of radiation-induced depolymerization and lower molecular weight [78,81,83] and decreased paracrystalline regularity [81,82]. For neutron exposure of cotton, onset of fibrillation has been reported at a dose of 10 11 neutrons cm À2 [89].…”

“…206]. Gamma and e-beam irradiation of equivalent energies produce equivalent changes in physical properties of fibers [83]; thermal neutrons and gamma rays are also equivalent in their effects [84][85][86]. Though all are cellulose-based fibers, acetate, rayon, and cotton, in decreasing order of stability, are susceptible to radiation damage [25,84].…”

“…Fading, discoloration, and changes in microscopic appearance were reported for synthetic fibers irradiated by gamma >10 kGy and natural fibers >50 kGy [25,89,90]. Forensic examination was deemed feasible, nevertheless [90,91].…”

The effect of quarantine-level gamma irradiation on cotton fiber and its subsequent textile processing performance

“…are found upon inspection at quarantine-approved premises.The effect of gamma radiation on cotton fiber was extensively studied in the late 1950s and early 1960s. [4][5][6][7][8][9][10][11][12][13][14][15][16] In these early studies, the dosages were generally extended to 1000 kGy and the cotton was most often sealed in N 2 or O 2 atmospheres or in minimal air…”

Electron Microscopy

“…Intern. Symposium on Microchem., Birmingham L'niv., (164) Wileox, R. E., Am. Mineralogist 44, 1958, pp.…”