【摘要】 在超临界甲醇中考察了反应温度、反应压力对聚对苯二甲酸二丁酯(PBT)的分解及单体对苯二甲酸二甲酯(DMT)收率的影响,在此基础上对PBT熔点前后的反应速度常数进行了求解.PBT的分解效果以DMT单体的生成量评价,并采用气相色谱和凝胶色谱(GPC)对液相产物的组成进行分析.结果表明:随反应温度的增加,单体对苯二甲酸二甲酯的回收率增加,250℃、10 min时可达92％;反应压力对PBT的分解几乎无影响;在:PBT熔点以上,分解反应速度常数明显增大,分解反应速度显著提高;熔点以上进行反应时,分解产物中低聚物的分子量降低,单体收率增加.更多还原

【Abstract】 The effect of reaction temperature and pressure on decomposition of polybutylene terephthalate ( PBT) and recovery of dimethyl terephthalate (DMT) monomer were investigated in supercritical methanol, and reaction velocity constants were calculated at temperatures above and under the PBT melting point. The dicomposing efficient of PBT was evaluated with the recovery of DMT monomer while the composition of liquid phase was identified that by Gas Chromatography and GPC analyzer. The results indicated that the amount of DMT increased with increasing reaction temperature and the recovery of DMT reached 92% when the reaction temperature approached 250 ℃ and with a reaction time 10 min. And the reaction pressure had little influence that on the decomposition of PBT. When temperature was over the PBT melting point, the decomposition reaction rate increased greatly. GPC analysis showed when the reaction took place above the PBT melting point temperature, the molecular weight of oligomers in decomposition products decreased, and the yield of monomer increased.更多还原