Control of molecular weight in tetrahydrofuran polymerization initiated by heteropolyacid
Control of molecular weight in tetrahydrofuran polymerization initiated by heteropolyacid
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DOI：
10.1002/app.1848
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发表时间：
2001-10-10
影响因子：
3
通讯作者：
Zhang, HZ
中科院分区：
文献类型：
--
作者：
Chen, Y;Zhang, GL;Zhang, HZ
无水和水合杂多酸均可用于在环氧乙烷促进剂存在下引发四氢呋喃聚合，其中水合杂多酸的结晶水作为额外加入的水的一部分用于控制分子量。分别通过不中和或中和并在聚合后用水洗涤的方法以超过50%的产率制备数均分子量为2000 ± 100或1000 ± 50的聚醚二醇。提出了一个基于聚合转化率、分子量控制剂和杂多酸浓度的修正方程，并加入修正因子，用于预测产物的数均分子量。通过核磁共振、凝胶渗透色谱和差示扫描量热分析对产物进行了表征。(C)John Wiley & Sons，Inc.
Both anhydrous and hydrated heteropolyacid can be used to initiate the tetrahydrofuran polymerization in the presence of ethylene oxide promoter, in regard to the crystallization water of the hydrated one as a part of the extra-added water for controlling the molecular weight. The polyether glycol having number-average molecular weight of 2000 +/- 100 or 1000 +/- 50 was prepared in yield beyond 50% by the process without neutralization or neutralization and washing with water after polymerization, respectively. A modified equation based upon conversion of polymerization and concentrations of molecular weight controller and heteropolyacid with a correction factor for predicting the number-average molecular weight of the product was given. The products were characterized by nuclear magnetic resonance, gel permeation chromatography, and differential scanning calorimetry analyses. (C) 2001 John Wiley & Sons, Inc.