NMR analysis of γ-radiation induced degradation of halthane-88 polyurethane elastomers

Abstract

We report 1H and 13C NMR analysis of changes in chain dynamics in a polyurethane elastomer system, Halthane 88-3, caused by exposure to 1.2 MeV gamma radiation from a Co-60 source. 1H NMR relaxation measurements clearly discriminate between interfacial, soft segment, and sol domains in the polymer. The 1H T 2 of the interfacial domain and the soft segment domain increased with the increased dose of γ-radiation. 13C CPMAS experiments also show that the hard segment domain remained unchanged up to cumulative dose of 100 kGray. The 1H and 13 C NMR results strongly suggest that the Halthane 88-3 elastomer undergoes chain scission, primarily in the long chains that make up the soft segments of the polymer. The NMR results are compared to results from DMA and a direct correlation between observables has been demonstrated.