Characterization of Complex Engineering Silicones by ~1H Multiple Quantum NMR and Large Scale Molecular Dynamics Simulations

摘要

Static ~1H Multiple Quantum Nuclear Magnetic Resonance (MQ-NMR) and large scale Molecular Dynamics (MD) simulations have been used to understand structure property relationships in silicone networks with bi- and tri-modal topology and with both micro- and nano-scale inorganic fillers. The MQ-NMR method characterizes the residual dipolar couplings of the silicone chains that depend on the average molecular weight between physical or chemical constraints. The MQ-NMR experiments allow for quantitative characterization of network structure in these crosslinked and filled systems. Large scale MD simulations have allowed for the characterization of structural perturbations due to the presence of filler particles and the effect of such particles on the composite elastomer's response to strain. Specifically, the polymer-filler network is shown to mitigate the risk of cavitation in the network under tensile strain.