Detection of inhomogeneties in rubber samples using n.m.r. imaging
Webb AG., Jezzard P., Hall LD., Ng S.
We have shown that direct magnetic resonance imaging of NR and its derivatives to determine the spatial homogeniety of the sample is feasible on short time scales, provided that suitable pulsed field gradients are available. The use of 3-D data acquisition enables samples of shorter T2values to be studied, than is possible using frequency-selective slice selection. Thus m.r.i. provides a totally non-destructive method for detecting inhomogeneities in rubber samples in their production state. If solvent ingress is possible, the long T2values of ingressed solvents (0.5-1 s) relative to the rubber samples themselves means that the increased signal-to-noise ratio from these solvents gives better resolution of inhomogeneities, and can determine the nature of these inhomogeneities. In addition, slice selection is now feasible using a long frequency selective pulse and experimental times can be correspondingly reduced.