Abstract: The irradiation effects on the aggregate state and microstructure of Xinjiang long-staple cotton fiber were studied by solid state ¹³C CP/MAS NMR, ¹H relaxation time measurements and ESR spectroscopy. The results showed that the microstucture of the long-staple cotton fiber were not altered after 5 Gy γ irradiation, while the crystallization state of the cotton fiber changed significantly under 75 Gy γ irradiation. It was also shown that γ irradiation induced production of different types of free radicals whose concentrations increased with the irradiation dose. The results of ¹H NMR relaxation time measurements suggested that γ irradiation could cause changes of molecular motions in the Xinjiang long-staple cotton fiber.

Key words: NMR, long-staple cotton fiber, ¹³C CP/MAS NMR spectra, ESR, relaxation time