Molecular dynamics predictions of thermomechanical properties of an epoxy thermosetting polymer
Molecular dynamics predictions of thermomechanical properties of an epoxy thermosetting polymer
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DOI：
10.1016/j.polymer.2020.122477
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发表时间：
2020-05-20
期刊：
影响因子：
4.6
通讯作者：
Tadmor, Ellad B.
中科院分区：
文献类型：
--
作者：
Fan, Jiadi;Anastassiou, Alexandros;Tadmor, Ellad B.
本文报道了用分子动力学(MD)模拟方法预测DGEBA树脂与JeffamineD230固化剂固化形成的热固性聚合物的热机械性能。采用多步交联法形成热固性聚合物的交联网。计算了分子动力学预测的交联结构的径向分布函数和X射线衍射图，并与实验结果进行了比较，验证了环氧网体系的有效性。利用德雷丁力场和琥珀力场，计算了不同温度和不同交联度下的热机械性能，如质量密度、凝胶点、玻璃化转变温度(T-g)、弹性模量(杨氏模数和剪切模数)、剪切和拉伸屈服强度等。分子动力学预测结果与理论研究和已有实验数据吻合较好。我们发现，随着交联度的提高，玻璃化转变温度和屈服强度都有显著的提高。弹性模量对应变率的敏感度较低，但屈服强度与应变率密切相关。在这项工作中开发的高质量数字环氧树脂配置以LAMMPS数据格式从期刊网站上获得。
This paper reports the thermomechanical properties of a thermosetting polymer formed by curing a DGEBA resin with a Jeffamine D230 agent predicted by molecular dynamics (MD) simulations. A multistep crosslinking approach is used to form the crosslinked network of the thermosetting polymer. The radial distribution function and X-ray diffraction pattern of the MD predicted crosslinked structure are calculated and compared with experimental results to validate the epoxy network system. Thermomechanical properties such as mass density, gel point, glass transition temperature (T-g), elastic moduli (Young's modulus and shear modulus), and yield strength in shear and tension are calculated at different temperatures and crosslinking conversions by employing the DREIDING and AMBER force fields. The MD predicted results are in good agreement with theoretical studies and existing experimental data. We find a significant increase in T-g and yield strength with crosslinking conversion. The elastic modulus is less sensitive to the strain rate, but the yield strength is significantly strain-rate dependent. The high-quality digital epoxy configurations developed in this work are available in LAMMPS data format from the journal website.