Estimation of crosslink density by solid-state NMR spectroscopy

The technique for estimating the extent of crosslinking in the individual phases of a blend by using peak broadening associated with increasing crosslink density, as described in Chapter 2, was developed on an instrument which is designed to obtain spectra of materials in a liquid state. Thus it is necessary to swell vulcanizates for several days before endeavouring to obtain a spectrum. The work described in this chapter has sought to establish whether the technique for estimating crosslink densities in the component rubbers of a vulcanized blend can be translated to a solid-state NMR spectrometer by adopting appropriate operating procedures, and thereby facilitate the estimation of crosslink densities in vulcanized blends.