Effect of conversion on epoxy resin properties: Combined molecular dynamics simulation and experimental study
Effect of conversion on epoxy resin properties: Combined molecular dynamics simulation and experimental study
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转化率对环氧树脂性能的影响：结合分子动力学模拟和实验研究
DOI：
10.1016/j.polymer.2022.125041
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发表时间：
2022
期刊：
影响因子：
4.6
通讯作者：
Yamashita Takefumi
中科院分区：
文献类型：
--
作者：
Shoji Naoyuki;Sasaki Kohei;Uedono Akira;Taniguchi Yuichi;Hayashi Keiichi;Matsubara Norie;Kobayashi Tetsuya;Yamashita Takefumi
我们研究了由双酚A二缩水甘油醚（DGEBA）和双-（对氨基环己基）甲烷（PACM）组成的环氧树脂，发现密度增加和减少，分别在低和高转化率区域，通过使用实验和全原子（AA）分子动力学（MD）模拟。为了定性地理解这一特征，我们进行了粗粒度（CG）MD模拟。对于柔性和刚性CG模型，计算的密度单调增加和减少，分别与实验密度。为了开发一个更真实的CG模型，这是表示为CG-EP，我们推导了基于AA-MD模拟的角度参数。结果发现，CG-EP成功地再现了实验密度的趋势，表明分子柔性的重要性。此外，随着转化过程的进行，自由体积空穴的尺寸单调增加，这与正电子湮没寿命谱的结果一致。此外，我们通过实验观察到，随着转化的进行，杨氏模量在50%处突然降低。CG分析表明，这种趋势也归因于分子的灵活性。
We investigated epoxy resin consisting of diglycidyl ether of bisphenol A (DGEBA) and bis-(p-aminocyclohexyl)methane (PACM) and found that the density increased and decreased in the low- and high-conversion regions, respectively, by using experiments and all-atom (AA) molecular dynamics (MD) simulations. To understand this feature qualitatively, we conducted course-grained (CG) MD simulations. For the flexible and rigid CG models, the calculated density increased and decreased monotonically, respectively, in contrast to the experimental density. To develop a more realistic CG model, which is denoted as CG-EP, we derived angular parameters based on AA-MD simulations. It was found that the CG-EP successfully reproduced the trend of the experimental density, suggesting the importance of molecular flexibility. In addition, the progress of the conversion monotonically increased the free volume hole size, which is consistent with the result of positron annihilation lifetime spectroscopy. Furthermore, we experimentally observed that the Young's modulus suddenly decreased at 50%, as the conversion progressed. The CG analysis indicated that this trend was also attributed to the molecular flexibility.