文献类型：期刊文献

中文题名：聚对苯二甲酸丁二醇酯在超临界甲醇中降解机理的研究

英文题名：The Depolymerization Mechanism of Polybutylene Terephthalate in Supercritical Methanol

作者：黄婕[1];齐文杰[1];黄科[1];吴勇强[1];朱子彬[1]

机构：[1]华东理工大学化学工艺研究所,上海200237

年份：2007

卷号：21

期号：1

起止页码：48

中文期刊名：高校化学工程学报

外文期刊名：Journal of Chemical Engineering of Chinese Universities

收录：CSTPCD;;EI(收录号：20071610557441);Scopus;北大核心:【北大核心2004】；CSCD:【CSCD2011_2012】；

基金：国家自然科学基金项目(20076013)

语种：中文

中文关键词：聚对苯二甲酸丁二醇酯;降解;超临界甲醇;降解机理

外文关键词：polybutylene tcrephthalate; depolymerization; supercritical methanol; mechanism

摘要：在高压间歇无搅拌反应器中研究了聚对苯二甲酸丁二醇酯(PBT)在高温甲醇溶液中的降解行为,通过对降解产物的各种定性和定量的分析,提出了超临界甲醇降解PBT的机理为在甲醇的作用下聚合物分子链的随机断裂和酯交换反应双重作用下发生的降解反应,建立了降解-反应模型。PBT在甲醇溶液中的降解可分为超临界区、非超临界区和中间过渡区三个区域。通过分子量测定考察了PBT在不同的区域中降解规律。在非临界区PBT在溶剂中处于溶胀状态,其数均分子量Mn下降缓慢,解聚程度低;在过渡区PBT的溶解性能提高,聚合物大分子发生断裂,降解速率加快;在超临界区,Mn随反应的进行而迅速下降,聚合物很快完全降解。在超临界区中PBT可实现完全降解,其主要产物为单体对苯二甲酸二甲酯(DMT)和丁二醇(BG),它们的收率可分别可达98.1%和72.3%。
Depolymerization experiments of polybutylene terephthalate （PBT） in supercritical methanol were carried out in a batch-type reactor with the reaction temperature of 453-583K and reaction time of 5-90 min. The degradation products were analyzed by GC/MS and HPLC/MS and their amounts were determined by GC/FID and HPLC. Based on the results of above operations, a dcpolymcrization reaction model was proposed to explain the reaction mechanism, i.e. Random scission and ester exchange reactions occur simultaneously which cause the dcpolymcrization of PBT. The experimental results show that the PBT decomposes mostly to its monomers, dimcthyl tercphthalate （DMT） and butylene glycol （BG）, by mcthanolysis in supercritical methanol, and the degradation of PBT can be divided into three regions, such as sub-critical region, transitional region and supcrcritical region. In the sub-critical region, the degradation reaction primarily occurs on the surface of PBT, which mainly shows as a swelling process, the dcgree of PBT degradation is low and its numerical average molecular weight Mn decreases slowly. In the transitional region, the solubility of PBT is enhanced, the scission of the large molecular polymers occurs and the degradation is speeding up. In the supercritical region, the PBT dissolves in the supercritical methanol quickly and the Mn decreases with the progress of the reaction rapidly, finally the PBT can be thoroughly dcpolymcrizcd in this region and the yield of monomer DMT and BG can reach 98.1% and 72.3% respectively.