Bernath Alexander, Kärger Luise, Henning Frank
Karlsruhe Institute of Technology, Institute of Vehicle System Technology, Chair for Lightweight Technology, Rintheimer Querallee 2, 76131 Karlsruhe, Germany.
Fraunhofer Institute for Chemical Technology, Joseph-von-Fraunhofer Str. 7, 76327 Pfinztal, Germany.
Polymers (Basel). 2016 Nov 3;8(11):390. doi: 10.3390/polym8110390.
In this work a holistic approach for the characterization and mathematical modeling of the reaction kinetics of a fast epoxy resin is shown. Major composite manufacturing processes like resin transfer molding involve isothermal curing at temperatures far below the ultimate glass transition temperature. Hence, premature vitrification occurs during curing and consequently has to be taken into account by the kinetic model. In order to show the benefit of using a complex kinetic model, the Kamal-Malkin kinetic model is compared to the Grindling kinetic model in terms of prediction quality for isothermal processing. From the selected models, only the Grindling kinetic is capable of taking into account vitrification. Non-isothermal, isothermal and combined differential scanning calorimetry (DSC) measurements are conducted and processed for subsequent use for model parametrization. In order to demonstrate which DSC measurements are vital for proper cure modeling, both models are fitted to varying sets of measurements. Special attention is given to the evaluation of isothermal DSC measurements which are subject to deviations arising from unrecorded cross-linking prior to the beginning of the measurement as well as from physical aging effects. It is found that isothermal measurements are vital for accurate modeling of isothermal cure and cannot be neglected. Accurate cure predictions are achieved using the Grindling kinetic model.
本文展示了一种用于快速固化环氧树脂反应动力学表征和数学建模的整体方法。主要的复合材料制造工艺，如树脂传递模塑，涉及在远低于最终玻璃化转变温度的温度下进行等温固化。因此，固化过程中会发生过早玻璃化，动力学模型必须考虑这一点。为了展示使用复杂动力学模型的优势，将卡马尔 - 马尔金动力学模型与格林德林动力学模型在等温加工预测质量方面进行了比较。从所选模型中，只有格林德林动力学模型能够考虑玻璃化。进行了非等温、等温以及组合差示扫描量热法（DSC）测量，并对其进行处理以供后续模型参数化使用。为了证明哪些DSC测量对于正确的固化建模至关重要，将两个模型都拟合到不同的测量数据集。特别关注等温DSC测量的评估，这些测量会受到测量开始前未记录的交联以及物理老化效应引起的偏差影响。结果发现等温测量对于等温固化的准确建模至关重要，不能被忽视。使用格林德林动力学模型实现了准确的固化预测。
