Material Property NMR Imaging of Cross-Linked Polymers Based on Longitudinal Relaxation in the Rotating Frame

Abstract

Material property (MAP) NMR imaging is a promising tool for the investigation of materials. It is based on relaxation weighted imaging, which is combined with a theoretical description to relate the measured NMR data, in this investigation represented by T1ρ relaxation values, with the property of the material one is interested in. Following this concept, T1ρ images with different strengths of the spin-lock amplitude have been acquired for a rubber sample consisting of three pieces of natural rubber with different cross-link densities. The data were evaluated using a defect diffusion model and transformed into images of the properties of the polymer network. Images related with the cross-link density and the power law of the T1ρ dispersion, which characterizes the molecular dynamics, have been calculated.