Investigation the physico-mechanical properties of PEBAX-1074: atomic-scale approach

In this study, structural, physical, mechanical, and transport properties of poly (ether-block-amide) copolymer with the trade name of PEBAX-1074 are simulated by molecular dynamics simulation (MD). The glass transition temperature (T_g), tensile, and fractional free volume (FFV) were simulated to evaluate the physical, structural, and mechanical properties of PEBAX-1074. Glass transition temperature (Tg) is consistent and is in good agreement with the experiment results. The simulated yield stress, ultimate strength, and Young's modulus values of PEBAX-1074 are converged were 5.7, 12.4, and 95 MPa, respectively. Furthermore, diffusivity, permeability, solubility, and permselectivity of CH₄ and CO₂ gases at three pressures (3, 5, and 7 bar) and operating temperatures (303, 318, and 328 K) were simulated. Results revealed that the diffusion coefficient, permeability, and solubility of both gases in PEBAX-1074 increment with enhancement pressure and temperature. Polymer chains gain enhanced segmental motion, and as a result, more diffusive jumps are conducted by the gas molecules at higher temperatures, and consequently, diffusion and permeability increase. Also, CO₂/CH₄ permselectivity increased and decreased with feed pressure and temperature, respectively. Simulated material properties are well consistent with experimental results. To decrease the number of expensive experiments and time-intensive simulations, this research involved a modification of the van’t Hoff-Arrhenius model. The sensitivity analysis and modification of this model enabled the simultaneous assessment of pressure and temperature effects on the membranes’ transport characteristics, such as solubility, diffusivity, and permeability, and revealed the good accuracy of the proposed model.