分子動力学法によるポリプロピレンの熱粘弾性挙動の数値シミュレーション Numerical Simulation of Thermo-Viscoelastic Behavior of Polypropylene by Molecular Dynamics
Generally, polymer materials such as polypropylene shows a strong time and temperature dependence (viscoelastic behavior). It is reported that deformation could be predict by applying time–temperature superposition principle to long-term viscoelastic behavior. In this study, whether time–temperature superposition principle completed in deformation was checked using a molecular dynamics. Therefore, stress-relaxation test and constant strain rate tensile test were employed for amorphous polypropylene by molecular dynamics. Stress-relaxation tests were performed in 5 temperature standards, and relaxation moduli were gotten. Using the results, master curve was drawn, and shift factor were gotten. Next, the constant strain rate tensile tests were performed in 4 strain speed and 5 temperature standards. The results agree well with the theory curve that demanded from the parameter mentioned above, and Arrhenius equation was applied between temperature–time. Furthermore, the temperature dependence of the volume was checked, and a flexural point was occurred in shift factor. This flexure point almost accorded with a glass transition point (307[K]). It was suggested that time–temperature superposition principle completed in the small transformation of polymer materials.
日本複合材料学会誌 42(2), 82-87, 2016