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

Abstract

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.magnified image

Assessment of femoral bone osteoporosis in rats treated with simvastatin or fenofibrate

“…This method is defined as an ill conditioned problem, but in the last decade a series of numeric procedures were developed [23,24] and are successfully used for Laplace analysis of NMR properties of various samples [25][26][27][28][29][30].…”

The heterogeneity of segmental dynamics of filled EPDM by 1H transverse relaxation NMR

“…The full decay of these curves was analyzed by one-dimensional Laplace-like inversion to obtain the distribution of filler-filler interactions. These distributions reveal the existence of week, medium, and strong filler-filler interactions, which were associated to the direct and indirect matrix-mediated filler-filler interactions [11].…”

“…[11]. Hereby the heterogeneous effects of reinforcing nano-particles were characterized by the Payne effect that was observed as decay curves of the storage modulus as a function of the shear-strain amplitude.…”

“…Various NMR methods have been implemented to describe the polymer segmental dynamics which are usually correlated with the elastomers macroscopic properties [7,8,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. These are based on the measurement of 1 H and 13 C longitudinal (T 1 ), transverse (T 2 ) and longitudinal in rotating frame (T 1q ) relaxation times [7,8,[11][12][13][14][15][16][17][18][19][20], multiple-quantum NMR [21][22][23][24][25], cross-polarization and 1 H magnetization exchange [20], Hahn echo [7,12,27], solidecho [17,28], and magic echo [29,30] decays were used to extract parameters that describe the segmental dynamics.…”

Detection of Iron Nanoparticles using Nuclear Magnetic Resonance Relaxometry and Inverse Laplace Transform

“…NMR relaxation time constant estimation using the exponential curve fitting (ECF) method was used to evaluate the quality of agricultural and food products (Kim and Kim, 2004;Kim and McCarthy, 2010). Inverse Laplace transform (ILT) is also another good alternative for calculating relaxation time constants of heterogeneous materials (Moldovan et al, 2010;Silva et al, 2012;Berman et al, 2013;Xu et al, 2014).…”