DNRF Centre "Glass and Time", IMFUFA, Department of Sciences, Roskilde University, Postbox 260, DK-4000 Roskilde, Denmark.
J Chem Phys. 2013 Sep 28;139(12):124506. doi: 10.1063/1.4821616.
We study chemical aging in "Cooee bitumen" using molecular dynamic simulations. This model bitumen is composed of four realistic molecule types: saturated hydrocarbon, resinous oil, resin, and asphaltene. The aging reaction is modelled by the chemical reaction: "2 resins → 1 asphaltene." Molecular dynamic simulations of four bitumen compositions, obtained by a repeated application of the aging reaction, are performed. The stress autocorrelation function, the fluid structure, the rotational dynamics of the plane aromatic molecules, and the diffusivity of each molecule are determined for the four different compositions. The aging reaction causes a significant dynamics slowdown, which is correlated to the aggregation of asphaltene molecules in larger and dynamically slower nanoaggregates. Finally, a detailed description of the role of each molecule types in the aggregation and aging processes is given.
我们使用分子动力学模拟研究了“库伊比特umen”中的化学老化。这个模型沥青由四种现实的分子类型组成：饱和烃、树脂油、树脂和沥青质。老化反应通过化学反应模型化：“2 个树脂→1 个沥青质”。对通过老化反应的重复应用获得的四种沥青组成进行了分子动力学模拟。确定了四种不同组成的应力自相关函数、流体结构、平面芳香族分子的旋转动力学以及每个分子的扩散系数。老化反应导致动力学明显减慢，这与沥青质分子在较大的、动力学较慢的纳米聚集体中的聚集有关。最后，详细描述了每种分子类型在聚集和老化过程中的作用。
