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

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 (T1ρ) 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. The Payne effect and proton low‐field NMR relaxation measurements such as transverse (T2), longitudinal (T1) and longitudinal relaxation times in rotating frame (T1ρ) are used to characterize the heterogeneity of filler/filler interactions and chain dynamics in a series of nanofilled EPDM elastomers. A broad variety of fillers with different contents (20 to 70 phr), particle sizes and surface active areas, like carbon black, silane and calcium‐carbonates, are studied.