超临界二氧化碳在聚氨酯体系中溶解和扩散行为的分子动力学模拟研究

发布时间：2018-08-20 17:40

【摘要】：超临界二氧化碳(scCO_2)在聚氨酯体系中的溶解和扩散行为对于聚合物加工和材料性能有重要影响。本论文利用分子动力学模拟方法计算分析了温度318～348K、压力10～40MPa范围内,CO_2在一系列多元醇以及聚氨酯反应产物中的溶解和扩散性能。论文首先研究了物性参数及操作条件对C0_2与多元醇相容性及CO_2扩散性能的影响,发现体系相容性随温度、分子量的增加而减小(低分子量情况相反),随压力、氧化丙烯单体(Propylene oxide,PO)含量的升高而增加,端基改性有利于增加体系的相容性;CO_2在多元醇中的扩散系数随温度的升高而变大,随压力、PO含量的增大而变小,端基改性使扩散系数减小;对比模拟结果与实验数据,发现聚合物-CO_2相互作用是决定体系相容性的主导因素。论文考察分析了多元醇官能度、端基、反应程度、温度和压力对CO_2与聚氨酯产物相容性及扩散性能的影响,结果表明官能度、压力的增加有利于增加体系相容性,而温度和反应程度增加、端基改性使体系相容性减小;CO_2扩散系数随多元醇官能度和温度的增加而变大,随反应程度和压力的提高而减小,多元醇羟基改性对CO_2在聚氨酯产物中的扩散是不利的。研究结果可以指导聚氨酯泡沫塑料配方原材料的选择,为超临界CO_2发泡制备聚氨酯微孔材料的工艺过程优化提供参考。
[Abstract]:The dissolution and diffusion behavior of supercritical carbon dioxide (scCO_2) in polyurethane system has an important effect on polymer processing and material properties. In this paper, the solubility and diffusion properties of COST2 in a series of polyols and polyurethane reaction products were calculated and analyzed by molecular dynamics simulation method in the range of temperature 318N 348K and pressure 10~40MPa. The effects of physical parameters and operating conditions on the compatibility of C02 with polyols and the diffusion properties of CO_2 were studied. It was found that the compatibility of C02 decreased with the increase of temperature and molecular weight (contrary to low molecular weight) and with pressure. The content of Propylene oxide-PO increased with the increase of content, and the diffusion coefficient of CO-2 in polyol increased with the increase of temperature and decreased with the increase of pressure PO content, and the modification of terminal group was beneficial to increase the compatibility of the system. Comparing the simulation results with the experimental data, it is found that the interaction of polymer-CO2 is the dominant factor to determine the compatibility of the system. The effects of functional degree, terminal group, reaction degree, temperature and pressure on the compatibility and diffusion properties of CO_2 with polyurethane products were investigated and analyzed. The results showed that the increase of functional degree and pressure was beneficial to increase the compatibility of the system. However, with the increase of temperature and degree of reaction, the compatibility of the system was reduced by the modification of the end group. The diffusion coefficient of COK2 increased with the increase of the functionalization and temperature of polyols, and decreased with the increase of reaction degree and pressure. The modification of polyol hydroxyl groups is unfavorable to the diffusion of CO_2 in polyurethane products. The results can guide the selection of raw materials for polyurethane foamed plastics and provide a reference for the optimization of the process of preparing polyurethane microporous materials by supercritical CO_2 foaming.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ328.3

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