首页> 外文学位 >A stability analysis of polymerization fronts.
【24h】

A stability analysis of polymerization fronts.

机译:聚合前沿的稳定性分析。

获取原文
获取原文并翻译 | 示例

摘要

Frontal Polymerization (FP) is a process of converting monomer into polymer via a localized zone that propagates through the monomer. It bears a strong resemblance to self-propagating high-temperature synthesis (SHS), which uses combustion waves to synthesize desired inorganic materials. The reaction front propagates through the coupling of thermal diffusion and the Arrhenius reaction kinetics of the exothermic polymerization process. This thesis utilizes a moving free-boundary model to describe free-radical FP. The focus of attention here is the self-sustaining wave which travels through the reaction vessel as polymer molecules are being formed. Numerical and analytical techniques are used to determine one-dimensional traveling waves, and stability analysis (linear and weakly nonlinear) of the reaction front is performed. It is then possible to suggest ways to curb instabilities in the propagating reaction front. After our initial analysis, we account for autoacceleration and determine its effect on frontal stability. In an effort to facilitate the propagation of weakly exothermic fronts, we consider a one-dimensional polymerization wave in a sandwich-type two-layer setting. First one layer is reactive while the other is considered to be inert. Heat exchange between layers is possible, and the effect this has on frontal stability is investigated. Next, we allow both layers to be reactive, thus further enhancing inter-layer heat exchange. We comment on the effect that the second reactive layer has on the basic state of the system. Finally, two future research directions are presented in detail. One of our goals is to determine how the propagating front is affected by bulk polymerization at the far end of the reaction vessel. This is an important aspect to be studied in greater depth and incorporated into existing FP models, since bulk reactions can influence the speed and long-term stability of the reaction front. We end with a theoretical discussion for the manufacture of polymer-dispersed liquid crystal films via FP.
机译:正面聚合(FP)是一种通过传播通过单体的局部区域将单体转化为聚合物的过程。它与自蔓延高温合成(SHS)非常相似,后者使用燃烧波来合成所需的无机材料。反应前沿通过放热聚合过程的热扩散和Arrhenius反应动力学的耦合传播。本文利用移动自由边界模型来描述自由基FP。此处关注的焦点是随着聚合物分子的形成而穿过反应容器的自持波。使用数值和分析技术确定一维行波,并对反应前沿进行稳定性分析(线性和弱非线性)。然后有可能提出抑制传播反应前沿不稳定的方法。经过初步分析,我们考虑了自动加速并确定了其对额叶稳定性的影响。为了促进弱放热前沿的传播,我们考虑了夹心式两层环境中的一维聚合波。第一层是反应性的,而另一层被认为是惰性的。层之间可以进行热交换,并研究其对正面稳定性的影响。接下来,我们让两层都具有反应性,从而进一步增强层间热交换。我们评论第二反应层对系统基本状态的影响。最后,详细介绍了两个未来的研究方向。我们的目标之一是确定在反应容器的远端,本体聚合如何影响传播前沿。这是一个重要的方面,需要更深入地研究,并结合到现有的FP模型中,因为本体反应会影响反应前沿的速度和长期稳定性。我们以通过FP制造聚合物分散液晶薄膜的理论讨论结束。

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