INVESTIGATION OF AGING IN POLYMER NETWORKS BY T-1-RHO MATERIAL PROPERTY NMR IMAGING

Material property (MAP) imaging was found to he a promising method for the investigation of aging processes in elastomer materials, Based on conventional parameter-selective imaging, MAP imaging directly reveal s the properties of the material by use of a theoretical description t o relate the measured nuclear magnetic resonance data-in this investig ation, T-1 rho values-with the properties of the material, Following t his concept, T-1 rho images with different strengths of lock amplitude have been acquired for a rubber sample consisting of four pieces of n atural rubber that were oxidatively aged under different conditions, T he data were analyzed using a defect-diffusion model and transformed i nto images of those material parameters, which were found to be suitab le for the characterization of the aging process, Images correlating w ith the crosslink density and the power law of T-1 rho dispersion were obtained indicating the degree of aging, (C) 1997 Elsevier Science In c.