Investigating mechanical properties of cross-linked SiO 2 and polyimide through molecular dynamics simulation
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Investigating mechanical properties of cross‑linked SiO2 and polyimide through molecular dynamics simulation Zhongyi Luo1,2 · Zichun Yang1,2 · Zhifang Fei1,2 · Gaohui Su1,2 Received: 15 May 2019 / Revised: 25 July 2019 / Accepted: 3 November 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract The cross-linked model of SiO2 and polyimide (SiO2–PI) was constructed through molecular dynamics simulation, and the mixture model of S iO2 and PI ( SiO2/PI) was also constructed for comparative analysis. The SiO2–PI model was constructed at the atomistic level to simulate the real polymerization procedure. By comparing the radial distribution function and interaction energy of the two models, covalent bonds have been formed and the reliability of the cross-linked model was confirmed. The mechanical properties of the two materials are calculated by the molecular dynamics and the improvement in mechanical properties has shown after the cross-linking. This improvement in the mechanical properties of the materials is analyzed theoretically with the conclusions of morphology and interaction energy. By comparing with similar materials, the results obtained in this paper are convincing. Thus, the cross-linked model can provide theoretical guidance for the improvement in the material properties. Keywords Molecular dynamics · Nano-composite · Mechanical properties · Free volume
Introduction Silica aerogel is a kind of super insulation material widely used in all walks of life because of its excellent thermal insulation performance. However, the problems of powder falling and slag dropping in practice have greatly restricted its application [1–3]. Therefore, its mechanical properties need to be optimized. The addition of organic compounds (polyimide [3–5], polyurethane [6, 7], etc.) to the silica aerogel can improve its mechanical properties. At the same time, if the pore structure of * Zhongyi Luo [email protected] 1
Institutes of High Temperature Structural Composite Materials for Naval Ship, Naval University of Engineering, Wuhan, China
2
School of Power Engineering, Naval University of Engineering, Wuhan, China
13
Vol.:(0123456789)
Polymer Bulletin
aerogels can be retained, the composites will still preserve its excellent properties. Therefore, the research on nano-composite materials broadens its practical application prospects. The purpose of this paper is to study the basic construction of the materials from the microstructure. The improvement in the mechanical properties of the nano-composite materials on the microscale and the influence of the interface between the composite materials are investigated through molecular dynamics simulation method. For more than 20 years, molecular dynamics simulation method has been used to obtain the time-dependent changes of structure and motion state by calculating the equations of motion of interacting multi-particle (molecule or atom). For the data which is hard or impossible to obtain from the experiments, molecular dynamics can simulate the
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