engleski

Orientational motions of chain segments in natural rubber crosslinked under uniaxial deformation

Natural rubber (NR) film was crosslinked by γ-irradiation in the state of uniaxial extension. The degree of deformation defined as λ’ = l/l0 (l0 and l being the lengths of relaxed and uniaxially deformed sample, respectively) was constant and equal 1.50, and the total irradiation dose was 300 kGy. Deuterium NMR spectroscopy, known as an extremely sensitive method on anisotropic molecular motion, was applied for the study of dynamic behaviour of polyisoprene chain segments. Perdeuterated cyclohexane was used as deuterium probe. NMR spectra indicate that segmental motions in NR film crosslinked under deformation are anisotropic. Moreover, spectra of NR film stretched in the direction parallel and perpendicular to the direction of deformation applied during the crosslinking process show an intrinsic difference in orientational behaviour of chain segments.

natural rubber; anisotropy; gamma-irradiation; uniaxial deformation; deuterium NMR; orientational dynamics.

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