Investigation of aging in polymer networks by T1 rho material property NMR imaging.
Material property (MAP) imaging was found to be a promising method for the investigation of aging processes in elastomer materials. Based on conventional parameter-selective imaging, MAP imaging directly reveals the properties of the material by use of a theoretical description to relate the measured nuclear magnetic resonance data--in this investigation, T1 rho values--with the properties of the material. Following this concept, T1 rho images with different strengths of lock amplitude have been acquired for a rubber sample consisting of four pieces of natural rubber that were oxidatively aged under different conditions. The data were analyzed using a defect-diffusion model and transformed into images of those material parameters, which were found to be suitable for the characterization of the aging process. Images correlating with the crosslink density and the power law of T1 rho dispersion were obtained indicating the degree of aging.
Barth
P
P
Fraunhofer-Institut für Biomedizinische Technik, Germany.
Hafner
S
S
D000465:Algorithms; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004058:Diffusion; D008279:Magnetic Resonance Imaging; D008422:Materials Testing; D008956:Models, Chemical; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D012408:Rubber / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors
D011108:Polymers; D012408:Rubber