The paper focuses on the problem of electrostatic interactions in molecular dynamics simulations of thermal properties of heterocyclic polymers. The study focuses on three thermoplastic polyimides synthesized on the basis of 1,3-bis-(3′,4-dicarboxyphenoxy)benzene (dianhydride R) and three diamines: 4,4′-bis-(4″-aminophenoxy) diphenylsulfone (diamine BAPS), 4,4′-bis-(4″-aminophenoxy) biphenyl (diamine BAPB), and 4,4′-bis-(4''-aminophenoxy) diphenyloxide (diamine BAPO). In the molecular dynamics simulations these polyimides were described by the Gromos53a5 force field. To parameterize the electrostatic interactions four methods of calculating the partial atomic charges were chosen: B3LYP/6–31G*(Mulliken), AM1(Mulliken), HF/6–31G*(Mulliken), and HF/6–31G*(ChelpG). As our parameterization is targeted to reproduce thermal properties of the thermoplastic polyimides, the choice of proper partial charges was finalized on a basis of the closest match between computational and experimental data for the thermal expansio