Detection of interfacial layers in elastomer samples by NMR imaging

The detection of interfacial layers in EPDM samples by NMR imaging is repor ted. Spin- and gradient-echo techniques were used to differentiate between Voids and inhomogeneities inside the elastomer by characteristic changes of the magnetic susceptibility. Layer-like structures were observed which res ult from folding of the material during the mixing process. The existence o f such interfacial layers may have significance for other analytical method s which probe bulk properties as well as for failure analysis.