Influence of the electrostatic interactions on thermophysical properties of polyimides: Molecular‐dynamics simulations |
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| Authors: | Stanislav G. Falkovich Sergey V. Lyulin Victor M. Nazarychev Sergey V. Larin Andrey A. Gurtovenko Natalia V. Lukasheva Alexey V. Lyulin |
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| Affiliation: | 1. Institute of Macromolecular Compounds, , Saint‐Petersburg, 199004 Russia;2. Department of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, , Petersburg, 198504 Russia;3. Theory of Polymers and Soft Matter, Department of Applied Physics, Technische Universiteit Eindhoven, , The Netherlands |
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| Abstract: | Revealing the way of how modification of the chemical structure of a polymer affects its macroscopic physical properties offers an opportunity to develop novel polymer materials with pre‐defined characteristics. To address this problem two thermoplastic polyimides, ULTEM? and EXTEM?, were simulated with small difference in chemical structures of monomer units, namely, the phenyl ring in ULTEM? was replaced by the diphenylsulphone group in EXTEM?. It is shown that such a small modification results in a drastic difference of the thermal properties: the glass transition temperature of EXTEM? is higher than that of ULTEM?. Our molecular‐dynamics simulations clearly demonstrated that it is the electrostatic interactions that are responsible for the observed difference in thermal properties of ULTEM? and EXTEM?: large partial charges of the sulphone group in the EXTEM? lead to strong dipole–dipole intra‐ and intermolecular interactions and correspondingly to an elevated glass transition temperature. © 2014 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014 , 52, 640–646 |
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| Keywords: | computer modeling EXTEM™ electrostatic interactions glass transition molecular dynamics polyimides simulations sulphone group structure-properties relations thermal properties thermoplastics ULTEM™ |
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