Influence of Monomer Size on CO₂ Adsorption and Mechanical Properties in Microporous Cyanate Ester Resins

Molecular simulations offer valuable insights into thermosetting polymers' microstructures and interactions with small molecules, aiding in the development of advanced materials. In this study, we design two cyanate resin models featuring monomers of different sizes and employ a previously developed method to generate crosslinked structures. We then analyze their crosslinking processes and physicochemical properties. Using quantum chemistry calculations and a GCMC/MD approach, we investigate CO₂ adsorption. Our results show that monomer size does not significantly affect the crosslinking process and provides a degree of polymerization as 83.8 ± 0.3% vs. 76.7 ± 1.4%, but it does influence key properties, such as the glass transition temperature (520 K vs. 420 K) and Young's modulus (2.32 GPa vs. 1.77 GPa). Moreover, CO₂ adsorption differs between the two models: the introduction of propyl ether moieties lowers by around 70% CO₂ uptake, indicating that specific adsorption sites impact gas adsorption. This study demonstrates a promising strategy for designing and optimizing thermosetting polymers with controllable gas separation and storage capabilities.