Thermodynamic analyses of the hydrogen bond dissociation reaction and their effects on damping and compatibility capacities of polar small molecule/nitrile-butadiene rubber systems: Molecular simulation and experimental study

摘要

Although the hydrogen-bonding damping theory of polar small molecule/polymer systems is widely accepted, optimal selection of small molecules and the ration of that with polymer is rarely achievable. Herein, we report a new molecular simulation way to attempt solving the above problems. A key point is to introduce the thermodynamic analyses of hydrogen bond dissociation reaction (HBDR). According to hydrogen-bonding damping theory, under the premise that Gibbs free energy is negative, the higher enthalpy, lower reaction equilibrium constant (KΘ), plus higher derivative of lnKΘto temperature of HBDR will lead to a better damping capacity. The above parameters obtained through quantum mechanics indicated that the relative damping capacity of three systems is AO-80/NBR?>?AO-70/NBR?>?AO-60/NBR. Unified linear relationship (R2?=?0.924) between normalized parameters (damping parameter (tanδmax) and energy dissipation parameter calculated by the thermodynamic parameters) was discovered in the combined three homogeneous systems. This work may help us better understand the structure-property of polar small molecule/polymer systems, and further provides new insights into the screening and design of high damping materials.