• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Thermal degradation of fire retardant formulations and dispersion of clay in polymer/clay nanocomposites.
【24h】

Thermal degradation of fire retardant formulations and dispersion of clay in polymer/clay nanocomposites.

机译：阻燃剂配方的热降解和粘土在聚合物/粘土纳米复合材料中的分散。

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

In general, fire retardancy is evaluated in terms of either self-extinguishing properties or the reduction in heat release rate. Since there is a close relationship between thermal degradation behavior of polymer and its fire retardancy, this dissertation mainly deals with the degradation behavior of fire retardant formulations.; In the case of self-extinguishing fire retardant formulations, many studies have focused on systems that exhibit synergistic fire retardant properties. However, no feasible fire retardant formulations showing synergistic fire retardancy have been developed since the introduction of the halogen/antimony fire retardant system. In this study, polycarbonate shows two main degradation pathways, which are chain scission of isopropylidene linkage and alcoholysis/hydrolysis of carbonate linkage. By incorporating aryl phosphate with polycarbonate, the carbonate linkages are stabilized, because the phosphates undergo the alcoholysis reaction more readily with the alcohol products decomposed from PC than does the carbonate linkage of PC. The synergistic fire retardant effect comes from the alcoholysis reaction between the degraded products and phosphate.; Through the degradation study of the clay composites of polystyrene (PS), polyamide 6 (PA6), poly(styrene-co-acrylonitrile) (SAN) and acrylonitrile-butadienestyrene (ABS), it appears that the common degradation pathway in polymer nanocomposites showing a large reduction in peak heat release rate (PHRR) is to have significant inter-chain reactions; PS/clay nanocomposites exhibit radical recombination and PA6/clay nanocomposites show increased inter-chain aminolysis/acidolysis. SAN/clay nanocomposites exhibit decreased radical recombination compared to that of PS/clay nanocomposites. The effect of the butadiene rubber component in ABS is to stabilize the SAN phase in terms of mass loss. Summarizing the above results, the well dispersed clay confines the degrading polymer during thermal degradation and this confinement permits further reactions, such as extensive random scission or inter-chain reactions. Therefore, it is possible that the degradation behavior can be correlated with the reduction in PHRR as a function of the extent of inter-chain reaction for many different polymers.; The relationship between the solubility parameter of the polymer and dispersion of clay was suggested through the study of model polymers having different solubility parameter and by including previously reported results. It was shown that the polymers having high solubility parameter readily form the nano-dispersed clay morphology and the type of surfactant is less important as long as the introduction of surfactant to the gallery enlarges the d-spacing of the clay.
机译：通常，阻燃性是根据自熄性或放热率的降低来评估的。由于聚合物的热降解行为与其阻燃性之间有着密切的关系，因此本文主要涉及阻燃剂配方的降解行为。在自熄性阻燃剂配方的情况下，许多研究集中于表现出协同阻燃性能的体系。然而，自引入卤素/锑阻燃剂系统以来，尚未开发出显示出协同阻燃性的可行的阻燃剂配方。在这项研究中，聚碳酸酯显示了两个主要的降解途径，即异亚丙基键的断链和碳酸酯键的醇解/水解。通过将磷酸芳基酯与聚碳酸酯结合，使碳酸酯键稳定，这是因为与PC的碳酸酯键相比，磷酸与由PC分解的醇产物更容易进行醇解反应。协同的阻燃作用来自降解产物和磷酸盐之间的醇解反应。通过对聚苯乙烯（PS），聚酰胺6（PA6），聚（苯乙烯-共-丙烯腈）（SAN）和丙烯腈-丁二烯苯乙烯（ABS）的粘土复合材料的降解研究，看来聚合物纳米复合材料中常见的降解途径表现出峰值放热率（PHRR）的大幅降低将导致显着的链间反应； PS /粘土纳米复合材料表现出自由基重组，而PA6 /粘土纳米复合材料表现出增加的链间氨解/酸解作用。与PS /粘土纳米复合材料相比，SAN /粘土纳米复合材料表现出降低的自由基重组。就质量损失而言，ABS中丁二烯橡胶组分的作用是稳定SAN相。总结以上结果，良好分散的粘土在热降解期间限制了降解的聚合物，并且该限制允许进一步的反应，例如广泛的随机断裂或链间反应。因此，对于许多不同的聚合物，降解行为可能与PHRR的降低有关，而PHRR的降低是链间反应程度的函数。通过对具有不同溶解度参数的模型聚合物的研究并包括先前报道的结果，提出了聚合物的溶解度参数与粘土分散体之间的关系。已经表明，具有高溶解度参数的聚合物容易形成纳米分散的粘土形态，并且表面活性剂的类型次要的并不重要，只要将表面活性剂引入到画廊中可以扩大粘土的d-间距。

著录项

  • 作者

    Jang, Bok Nam.;

  • 作者单位

    Marquette University.;

  • 授予单位 Marquette University.;
  • 学科 Chemistry Organic.; Chemistry Polymer.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 199 p.
  • 总页数 199
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 有机化学;高分子化学（高聚物）;
  • 关键词

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