In the printing, coating and ink industries, photocurable systems are becoming increasingly popular and multi-functional acrylates are one of the most commonly used monomers due to their high reactivity (fast curing). In this paper, we use molecular dynamics and graph theory tools to investigate the thermo-mechanical properties and topology of hexanediol diacrylate (HDDA) polymer networks. The gel point was determined as the point where a giant component was formed. For the conditions of our simulations, we found the gel point to be around 0.18 bond conversion. A detailed analysis of the network topology showed, unexpectedly, that the flexibility of the HDDA molecules plays an important role in increasing the conversion of double bonds, while delaying the gel point. This is due to a back-biting type of reaction mechanism that promotes the formation of small cycles. The glass transition temperature for several degrees of curing was obtained from the change in the thermal expansion coefficient. For a bond conversion close to experimental values we obtained a glass transition temperature around 400 K. For the same bond conversion we estimate a Young's modulus of 3 GPa. Both of these values are in good agreement with experiments.

中文翻译：

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对己二醇二丙烯酸酯（HDDA）的自由基聚合进行建模：分子动力学和图论方法†

在印刷，涂料和油墨行业中，可光固化体系正变得越来越流行，并且多官能丙烯酸酯由于其高反应性（快速固化）而成为最常用的单体之一。在本文中，我们使用分子动力学和图论工具研究了己二醇二丙烯酸酯（HDDA）聚合物网络的热机械性能和拓扑。胶凝点被确定为形成巨型组分的点。对于我们的模拟条件，我们发现胶凝点约为0.18键转换。对网络拓扑的详细分析出乎意料地表明，HDDA分子的柔韧性在增加双键的转化率，同时延缓胶凝点方面起着重要作用。这是由于反作用类型的反应机制促进了小循环的形成。从热膨胀系数的变化中获得了用于几度固化的玻璃化转变温度。对于接近实验值的键转化，我们获得了约400 K的玻璃化转变温度。对于相同的键转化，我们估计的杨氏模量为3 GPa。这两个值都与实验非常吻合。