INFLUENCE OF CO-60 GAMMA-RAY IRRADIATION ON THE MORPHOLOGY OF CRYSTALLINE POLYETHYLENE STUDIED BY HIGH-RESOLUTION SOLID-STATE C-13 NMR

The relationship and influence of varying Co-60 gamma-ray irradiation doses, in the range 0.77-5.2 MGy, on the morphology of polyethylene ha ve been investigated using high-resolution solid-state C-13 nuclear ma gnetic resonance analyses through variation of different phase compone nts, T-1cr T-2c relaxation parameters, and line width. The cross-linki ng in the irradiated polyethylene takes place mainly in the non-crysta lline regions. However, distortion and damage to the folded chain of t he crystal lattice are observed in the crystalline regions. For the in terfacial phase, both cross-linking and distortion could occur. As a r esult, part of the crystalline component transformed into a non-crysta lline one. It was also found that the orthorhombic crystalline lattice transformed into a monoclinic one within the crystalline phase in pol yethylene under higher doses of irradiation.