SECTION: Physics, Nanotechnologies, Materials Technology, Space
SCIENTIFIC ORGANIZATION:
Institute of Macromolecular Compoundsof the Russian Academy of Sciences
REPORT FORM:
«Poster report»
AUTHOR(S)
OF THE REPORT:
V. Nazarychev, S. Lyulin, S.Larin, S. Falkovich, I. Gofman, J. Kenny, A. Lyulin
SPEAKER:
Victor Nazarychev
REPORT TITLE:
Mechanical properties of crystallizable polyimides. molecular-dynamics simulation
TALKING POINTS:

To study the influence of the chemical structure of high-performance heterocyclic polymers on their mechanical properties the uniaxial deformation of three heat-resistant heterocyclic polyimides, R-BAPS, R-BAPB and R-BAPO, has been investigated by microsecond-scale molecular-dynamics computer simulations. These polyimides have been synthesized based on dianhydride R (1,3-bis(3',4-dicarboxyphenoxy)benzene) and diamines BAPS (4,4´-bis-(4´´-aminephenoxy) diphenylsulfone), BAPB (4,4'-bis-(4''-aminophenoxy) diphenyl), and BAPO (4,4´-bis-(4´´-aminophenoxy) diphenyloxide).

The influence of a wide range of external parameters (equilibration degree, polymerization degree, temperature, cooling rate, external hydrodynamic pressure and external loading) on simulated mechanical characteristics has been investigated. The results obtained agree qualitatively with the corresponding experimental data.

It is shown that the elasticity modulus depends almost logarithmically on cooling and deformation rates. Taking into account this dependence, we can reproduce the experimental ratio between the values of the elasticity moduli for three simulated polyimides (R-BAPS, R-BAPB, and R-BAPO) within error bars. For the first time the influence of the graphene nano-sheets on mechanical properties of the crystallizable polyimide matrices has been shown. In fact, adding of graphene leads not only to an increase of the anisotropy of mechanical properties, but also to the increase of the average elasticity modulus.

The obtained results have demonstrated the rather powerful predictive ability of the suggested simulation approach for the development of new high-performance materials with improved mechanical properties.

Acknowledgements.

This study has been supported by the Russian Ministry of Education and Science within State Contract No. 14.Z50.31.0002. The simulations were carried out using the computational resources of the Institute of Macromolecular Compounds, Russian Academy of Sciences, and the Chebyshev and Lomonosov supercomputers at Moscow State University.