...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >Real time dielectric monitoring of glass transition in n-vinyl pyrrolidone polymerization
【24h】

Real time dielectric monitoring of glass transition in n-vinyl pyrrolidone polymerization

机译：正乙烯基吡咯烷酮聚合中玻璃化转变的实时介电监测

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

Real time dielectric spectroscopy was used for monitoring the dynamics during liquid glass transition in radical bulk polymerization of n-vinyl pyrrolidone. Two different relaxation mechanisms were identified. Initially segmental alpha-relaxation was dominant. Subsequently, contribution from slower motions became more significant and epsilon '(t(r),omega) underwent maxima in all frequency bands up to 10 MHz. Peak amplitude increased and the occurring time was delayed with decreasing frequency. The slow region dynamics were similar to the dynamics of Chamberlin's domain-like model of glass transition. The glassy phase is formed by a segmental relaxation and a relaxation due to glassy regions, The characteristic relaxation times of slow and segmental motions were well described by a modified Vogel-Fulcher-Tammann relation. The high frequency behavior, associated with the segmental motions, is well described by Havriliak-Negami and Kohlrausch-Williams-Watts formulas, which did not provide satisfactory fittings for the dynamics of slow regions. Both real and imaginary parts of the dielectric data were fully described by a complex dielectric relaxation function, the parameters of which are found by the eigen-coordinates (EC) method. (c) 2007 Elsevier B.V. All rights reserved.
机译：实时介电谱用于监测正乙烯基吡咯烷酮的自由基本体聚合中液体玻璃化转变过程中的动力学。确定了两种不同的松弛机制。最初，节段性α松弛是主要的。随后，慢动作的贡献变得更加显着，ε'（t（r，ω））在最高10 MHz的所有频带中都达到最大值。峰值幅度增加，发生时间随频率降低而延迟。缓慢的区域动力学类似于张伯林的玻璃化转变的类畴模型的动力学。玻相是由分段弛豫和由于玻璃状区域引起的弛豫形成的。通过修正的Vogel-Fulcher-Tammann关系很好地描述了慢速运动和分段运动的特征弛豫时间。 Havriliak-Negami和Kohlrausch-Williams-Watts公式很好地描述了与分段运动相关的高频行为，但这些公式不能为慢速区域的动力学提供令人满意的拟合。介电数据的实部和虚部均由复数介电弛豫函数完整描述，其参数通过本征坐标（EC）方法找到。 （c）2007 Elsevier B.V.保留所有权利。

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