Application of single-pulse solid-state 1H-MAS NMR to probe the oxidation products in crosslinked polyethylene: A detailed spectral analysis procedure

A spectral analysis procedure for single-pulse 1H-MAS spectra acquired at 20 kHz MAS-rate is presented and thoroughly discussed and demonstrates that all relevant functional groups can be identified and quantified. In particular, the present technique finds special application in the analysis of oxidation products formed during ageing of cross-linked polymers, which are generally difficult or impossible to study by solution state NMR, since these polymers are mostly insoluble.The main objective and advantages of applying 1H-MAS solid-state NMR compared to liquid state 13C NMR are related to; 1) a much shorter experimental sampling time, on the order of a few minutes, 2) the bypass of sample preparation, as compared to traditional high-resolution liquid state 13C NMR which requires a high temperature (130 °C) preparation period of days, or even weeks and 3) the technique is non-destructive. Finally, the present technique gives a much easier access to quantitative information compared to solid-state 13C-CPMAS NMR.