Heterogeneity of Nanofilled EPDM Elastomers Investigated by Inverse Laplace Transform 1H NMR Relaxometry and Rheometry

摘要

The heterogeneous effects due to filler interactions and chain dynamics of reinforcing nano-filler particles were characterized on a series of filled EPDM elastomers using the Payne effect and low field NMR, 1H transverse (T₂), longitudinal (T₁) and longitudinal in rotating frame (T_1ρ) relaxation time measurements. Measurement of the Payne effect and NMR relaxation curves were used to obtain the distribution of filler/filler interactions and chain dynamics by one-dimensional Laplace inversion. Distributions of shear-strain constants in the Payne effect reveal the existence of weak, medium and strong filler/filler interactions which were correlated to filler properties and content. The analysis of relaxation-time distributions leads to the identification of multimodal polymer network dynamics.