Long-chain branching increased vinyl concentration

Irradiation of Marlex 6003 Polyethylene. Results of 13c NMR measurements on Phillips Marlex 6003 polyethylene both prior to and just following a 2.0 Mrad irradiation in vacuum and 298 K are presented in Table IV. The spectra from which these data were obtained are shown in Figures 4 and 5. These results indicate that irradiation of high density polyethylene in vacuum in the solid state reduces the concentration of terminal vinyl unsaturations and increases the concentrations of long chain Y branches, saturated end groups and trans double bonds. The H-link could not be detected following an irradiation of Marlex 6003 in the solid state. 

Figures 9 and 10. The results for NBS 1475 are similar to those obtained from the study of Marlex 6003 after irradiation in the solid state. Once again, the concentrations of long chain Y branches, saturated end groups and trans double bonds apparently increase with irradiation while the concentrations of terminal vinyl groups decrease with irradiation. There is some scatter in the data as might be expected for concentrations measured in the range of 1-3 per 10,000 carbon atoms. As was the case for Marlex 6003, the presence of any appreciable quantity of H-links was not detected. Thus the H-link concentration must be well below one per...

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