Research Equipment Grants: An Advanced Thermal Analysis System for Macromolecular Coal Studies

将使用先进的热分析系统在高温(250-400℃)下研究各种渗透剂在具有良好特性的薄煤片中的传输，以努力研究煤的高度交联网络结构中的传输机制，并阐明溶剂在改变其化学结构中的作用。实验研究将在高于和低于Tg的高温下进行，使用厚度从20到1000&gt；m的薄片。此外，我们还将通过多官能团甲基丙烯酸酯如二‘，三’和四甲基丙烯酸酯的反应合成高度交联的聚合物。这种聚合物体系是玻璃化的，具有高的玻璃化转变温度和明确的交联结构。在与煤网络相同的渗透剂中，它们将通过动态和平衡研究而膨胀。然后，将这两种研究的结果进行比较，以阐明交联型煤网络结构的性质。将开发数学模型来描述煤中渗透剂(溶剂)的不寻常传输。这些结果将直接适用于阐明煤加工过程中的传质限制、溶剂在改变化学稳定性中的重要性以及分子解离机理。所要求的设备，先进的热分析系统，将被用来在高温下分析大分子煤的结构。差示扫描量热仪模块将提供作为渗透剂含量函数的大分子煤网络结构的玻璃化转变温度。热力学和动态力学分析部分将阐明在渗透剂存在的情况下，煤网络在玻璃化转变温度以下、附近和以上的粘弹性行为。热重分析模块将被用来获得高温下的渗透吸收数据，并将扩散和松弛机制分离。

The transport of various penetrants in well characterized, thin sections of coal will be examined at high temperatures (250-400>C) using an Advanced Thermal Analysis System in an effort to investigate the mechanisms of transport in the highly crosslinked network structure of coal and to elucidate the effort of solvents in altering its chemical structure. Experimental Studies will be performed at high temperatures both above and below Tg using thin sections varying in thickness from 20 to 1000 >m. In addition we will synthesize highly crosslinked polymers by reaction of multifunctional methacrylates such as di', tri' and tetramethacrylates. Such polymer systems are glassy with high glass transition temperatures and well defined crosslinked structures. They will be swollen both by dynamic and equilibrium studies in the same penetrants as the coal networks. Then, the results from these two investigations will be compared in order to elucidate the nature of the crosslinked coal network structure. Mathematical models will be developed to describe the unusual transport of penetrants (solvents) in coal. These results will have direct applicability in the elucidation of the mass transfer limitations in coal processing, the importance of solvents in altering chemical stability and the mechanisms of molecular dissociation. The requested equipment, Advanced Thermal Analysis System, will be used to analyze the macromolecular coal structure at high temperature. The differential scanning calorimetry module will provide the glass transition temperature of the macromolecular coal network structure as a function of a penetrant content. The thermomechanical and dynamic mechanical analysis components will elucidate the viscoelastic behavior of coal networks below, around and above their glass transition temperature in the presence of penetrants. The thermogravimetric analysis module will be used to obtain penetrant uptake data at high temperature and to decouple the diffusional and relaxational mechanisms.