Designing Thermally Resistant Polyimide Oligomers: Insights from Molecular Dynamics Simulations

We perform a systematic computational study for designing high-temperature resistant Oligo-polyimides (Oligo-PIs). Their properties can be significantly enhanced by substituting the diamine component. Oligo-PI Type A– end-capped with 4-Phenylethynyl anhydride (4-PEPA) groups and comprising of 11 repeat units of 1,3-Bis(4-aminophenoxy)benzene (TPE-R) and 10 repeat units of 3,4′-Biphthalic Anhydride (a-BPDA)) was chosen for modification. We selected 4-PEPA and a-BPDA due to their efficacy in forming thermally stable Oligo-PIs. Here, we developed a molecular modification approach to substitute the Oligo-PI Type A TPE-R segment with various commercially available polyimide (PI) monomers. This method, integrated with high-fidelity molecular dynamics simulations, allowed us to quantitatively predict the glass transition temperature (T_g) and identify 27 Oligo-PI candidates demonstrating structural integrity above 823 K, the conventional turbine inlet gas temperature. Posteriori structural analysis revealed important structural attributes such as side group, symmetry and configuration, chain–chain interactions, and molecular symmetry, which are crucial to their high T_g. This strategy demonstrates a promising method for the tailored design of high-temperature resistant materials, paving the way for advancements in gas turbine materials.