Investigation of ageing processes and crosslink density inhomogeneities by parameter selective NMR microscopy

Summary form only given: The aim of the author´s work is to demonstrate the potential of NMR imaging for spatially resolved determination of material properties. T₁,T₂,T_1p-imaging experiments were performed on aged technical rubber samples and of such with different crosslink densities as well. The NMR data were analysed using the BPP and Anderson-Weiss theory (BPP-AW) and the theory of Limited Translational Defect Diffusion (LTDD). The results reveal the different frequency components of the molecular motion, the nonaveraged dipolar interaction q*M₂ and the crosslink density. From LTDD theory the defect size of chain entanglements, diffusion distance and defect diffusion coefficients could be derived. Histogram analysis of all parameters derived from the data evaluation shows clearly crosslink density inhomogeneities