...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Macromolecular symposia >The Ring-Opening Polymerization of ε-Caprolactone Catalyzed by Molybdenum Trioxide: A Kinetic Approach Study Using NMR and DSC Data
【24h】

The Ring-Opening Polymerization of ε-Caprolactone Catalyzed by Molybdenum Trioxide: A Kinetic Approach Study Using NMR and DSC Data

机译：三氧化钼催化ε-己内酯的开环聚合：使用NMR和DSC数据的动力学方法研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The bulk ring-opening polymerization (ROP) of ε-caprolactone (CL), catalyzed by molybdenum trioxide (α-MoO_3), was investigated under nitrogen atmosphere at 150℃. Effect of monomer/initiator ([CL]_0/[I]_0, I=MoO_3) and monomer/ initiator/co-initiator ([CL]_0/[I]_0/[CoI]_0, CoI=ROH and H_2O) ratios on monomer conversion and molecular weight were determined. Bulk polymerization of CL was completed within 20 hours at 150℃ for [CL]_0/[I]_0=100. Propagation was first order in CL concentration and initiator at this temperature, being the rate constant of propagation k_p equal to 2.27×10~(-4) mol~(-1) I s~(-1). Polymerization reaction was accelerated by the addition of small amounts of water and n-octanol. In the presence of water (up to [CL]_0/[H_2O]_0=120), polymerization rate increases and was completed within 6 hours at 150℃; for higher amounts of water (150 to 180), lower conversions are observed. However, control of number-average molecular weight was only efficient for [CL]_0/[H_2O]_0=20 and 30. In the presence of n-octanol, degradation of polyester occurs at early stages of polymerization. Kinetic data for polymerization (obtained by ~1H-NMR) were fitted to 14 different model reaction functions. It was found that a linear model represents better the conversion versus time plots for bulk polymerization, in agreement with the pseudo living nature of polymerization.
机译：在150℃的氮气氛下，研究了三氧化钼（α-MoO_3）催化的ε-己内酯（CL）的本体开环聚合（ROP）。单体/引发剂（[CL] _0 / [I] _0，I = MoO_3）和单体/引发剂/共引发剂（[CL] _0 / [I] _0 / [CoI] _0，CoI = ROH和H_2O）的作用确定了单体转化率和分子量的比率。在[CL] _0 / [I] _0 = 100的条件下，于150℃在20小时内完成了CL的本体聚合。在此温度下，CL浓度和引发剂的传播是一阶的，即传播常数k_p等于2.27×10〜（-4）mol〜（-1）I s〜（-1）。加入少量水和正辛醇可加速聚合反应。在水（高达[CL] _0 / [H_2O] _0 = 120）存在下，聚合速率增加，并在150℃6小时内完成。对于较高量的水（150至180），观察到较低的转化率。然而，数均分子量的控制仅对[CL] _0 / [H_2O] _0 = 20和30有效。在正辛醇存在下，聚酯的降解发生在聚合反应的早期。聚合反应的动力学数据（通过1H-NMR获得）适用于14种不同的模型反应函数。发现线性模型代表本体聚合的转化率与时间图更好，这与聚合的拟活性有关。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号