【作者】 李响；

【导师】 陆慧林；

【作者基本信息】 哈尔滨工业大学 ， 热能工程， 2006， 硕士

【摘要】 聚氨酯作为一种化学、物理性能皆优的高分子聚合材料,已经逐步取代一些传统塑料,广泛应用于建筑、航空、汽车制造、医药等领域。然而如何处置利用废弃聚氨酯是一个严峻的环境问题。常用的土地填埋、直接焚烧等方式已经越来越不适用当今社会环保的要求。化学分解法目前被视为经济效益和环境保护兼优的处置方法。本文就热分解法对聚氨酯硬泡和软泡塑料进行试验和理论对比研究,以期得到产物分布情况和活化能值。通过对聚氨酯硬泡和软泡的实验热重曲线和热差分析曲线进行比较,可以发现随着升温速率的提高整个热解反应都朝着高温区平移,热解起始温度提高,最大热解速率减小。聚氨酯软泡发生热解的区域集中在170℃与500℃之间,而聚氨酯硬泡发生在200℃与410℃之间。在氮气氛围下选用四种升温速率,对两种聚氨酯进行热解实验研究。随着给定热解温度的提高,固体残余物减少有利于热反应进行。随着升温速率的提高,固体产物和气体产物都有相应的增加而液体产物呈减少趋势。随着热解停留时间的延长,液体产物和气体产物都相应增加,而固体残余物明显减少。GC/MS分析检测到两种聚氨酯的液态产物中共同含有苯胺和P-甲苯胺。在聚氨酯硬泡热解液中检测到5种主要的化学成分,而聚氨酯软泡中则含有11种成分。研究认为聚氨酯软泡软段中含多种脂肪烃是影响两种聚氨酯差异的主要因素。并通过Chemkin软件预测了生成反应物苯乙烯的基元反应。它由基元团C4H6、C6H8、C6H5和C2H4通过一系列基元反应获得。本文建立的反应动力学模型较好重现了实验数据,并得到了一系列动力学参数。随着升温速率的提高,聚氨酯硬泡塑料的活化能呈下降趋势,而软泡塑料却恰好相反。聚氨酯硬泡和软泡的平均活化能分别为127.7KJ/mol和203.1KJ/mol。聚氨酯软泡塑料平均活化能是聚氨酯硬泡的1.59倍。更多还原

【Abstract】 Polyurethanes are macromolecular polymers which have well performances in chemical and physical. They replace the parts of older plastic and are applied in many spheres, such as construction industries, aerospace, automotive, medical. But how to treat and utilize refused plastic was produced, which is a severe environmental problem. The common treatment, such as landfill and direct incineration, cannot fit to environment now. Chemical decomposition was applied as a better treatment which is beneficial to economic and environment. In this paper, pyrolysis was adopted for comparing hard and soft polyurethanes in experiment and mechanism to analysis distribution of products and get activation energies.Comparison of TG and DTA curves of two polyurethanes, the result that decomposition of polyurethanes is a multitude of physical and chemical processes was confirmed. The initial degraded temperature increases, maximum decomposition velocity decreases and the whole decomposition process moves to higher temperature range with heating rate elevated. The components of hard polyurethane composed between 200℃and 410℃, as well as, soft polyurethane appeared between 170℃and 500℃. In nitrogen and at four different heating rates, experiments of two kinds of polyurethanes were operated. Following the pyrolysis temperature given increasing, solid residues decreased and it is in favor of thermal decomposition. With heating rate increasing, solid and gas products were increased and liquid product decreased. Longer residence time more liquid and gas products and less solid residue. By GC/MS analysis, Aniline and P-Aminotoluene all were detected in liquid products of hard and soft polyurethanes. And five main chemical component in products of hard polyurethane and eleven ones in soft polyurethane were shown. Fatties in soft polyurethane are the key of difference of two polyurethanes. The elementary reaction for styrene was forecasted by Chemkin software. It was produced from C4H6、C6H8、C6H5 and C2H4 through a series of elementary reactions. For studying pyrolysis kinetics, a kinetic model was built. By this way, a series of kinetics parameters of polyurethanes at different heating rates were gotten. The activation energy of hard polyurethane decreased following heating rate improved, in contrast, the trend of the activation energy of soft polyurethane increased. The average activation energies of hard and soft polyurethanes are 127.7KJ/mol and 203.1KJ/mol respectively. That of soft polyurethane is 1.59 times as many as one of hard polyurethane.更多还原