• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>Conference on Recent Advances in Flame Retardancy of Polymeric Materials >Benefits of Radical Generators in Flame Retarded Polymers: Review and New Developments (PPT)
【24h】

Benefits of Radical Generators in Flame Retarded Polymers: Review and New Developments (PPT)

机译：激进发电机在阻燃聚合物中的好处：审查和新的发展（PPT）

获取原文
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Radical generators as synergists in flame retarded polymers have been used in combination with brominated flame retardants for decades. However, due to the low thermal stability of radical generators under the usual polymer processing conditions the use was limited to selected applications e.g. in polystyrene foams. The need to find efficient halogen free flame retardants resulted inter alia in the discovery and commercialization of hindered amine light stabilizers based on alkoxyamines (NOR-HALS). NOR-HALS provide flame retardancy of polypropylene and polyolefin fibers, non-wovens and films. The performance of the NOR molecules depends on their structure i.e. the capability to degrade into nitroxyl plus alkyl or aminyl plus alkoxy radicals. Through formation of radicals a fast degradation of the polymer chain is induced and flame retardancy is achieved by removing the substrate from the flame. On the other hand, the formed radicals are involved in the free radical chemical reactions during the combustion process. Furthermore, alkoxy amines can interact with brominated flame retardants and facilitate the release of bromine, consequently increasing the overall FR performance. Therefore, it is possible with NORs to design flame retardant polyolefin molding compositions with lower levels of halogenated flame retardants and, in addition, to eliminate antimony trioxide. Moreover the hindered amine (HALS) structure provides light and long-term thermal stability of flame retarded formulations. Following the success of NOR based flame retardants a number of alternative radical generator molecules have been identified namely azo compounds, triazenes, hydrazones and azines. Especially combinations of Azo and NOR structures in one molecule show increased performance at loadings as low as 0.5 % in polypropylene films, including light and long-term thermal stability, and act synergistically with halogen, phosphorus and inorganic flame retardants. Although the performance of alkoxyamines in thin sections such as films is well documented and the UL 94 V-2 classification is often obtained in moldings, formulations usually fail in achieving the UL 94 V-0 classification as burning drips cannot be avoided despite short burning times. For the first time a new class of nitrogen based radical generators can be presented whereas in combination with selected phosphorus derivatives flame retarded polypropylene with UL 94 V-0 classification is accessible. Thermal stability and degradation of the new class into radicals is correlated to the molecular structure and can be adjusted in line with the degradation of the polymer and the synergist. Moreover the necessary loadings to achieve UL 94 V-0 are below 10 %.
机译：作为阻燃聚合物中的增效剂的激进发生器已与数十年结合使用溴化阻燃剂。然而，由于在通常的聚合物加工条件下自由基发生器的低热稳定性，使用仅限于所选择的应用。在聚苯乙烯泡沫中。尤其是基于烷氧基胺（NOR-HALS）的受阻胺光稳定剂的发现和商业化的需要尤其导致高效的卤素免阻燃剂。 NOR-HALS提供聚丙烯和聚烯烃纤维，非织造织物和薄膜的阻燃性。 NOR分子的性能取决于它们的结构I.E。能力降解到硝基苯基加烷基或氨基加烷氧基中。通过形成自由基，诱导聚合物链的快速降解，通过从火焰中除去基材来实现阻燃性。另一方面，所形成的自由基涉及在燃烧过程中的自由基化学反应中。此外，烷氧基胺可以与溴化阻燃剂相互作用，并促进溴的释放，从而提高整体FR性能。因此，可以使用NOR来设计具有较低水平的卤化阻燃剂的阻燃聚烯烃模塑组合物，并且还可以消除三氧化锑。此外，受阻胺（HALS）结构提供了火焰延迟制剂的光和长期热稳定性。在不基于的阻燃剂的成功之后，已经鉴定了许多替代的自由基发生器分子，即偶氮化合物，三聚糖，腙和氮杂氨酸。特别是一个分子中AZO和结构的组合，并且在聚丙烯薄膜中增加了低至0.5％的载荷的增加，包括光和长期热稳定性，并用卤素，磷和无机阻燃剂协同作用。尽管诸如薄膜的烷氧基胺的性能良好地记录了薄片，但是在模制品中通常获得UL 94 V-2分类，但是通常在实现UL 94 V-0的分类时，尽管燃烧时间短，但燃烧的滴度也不能避免燃烧滴度。首次呈现新的基于氮的自由基发生器，而与选定的磷衍生物阻燃聚丙烯的组合可获得UL 94 V-0分类。新类进入自由基的热稳定性和降解与分子结构相关，并且可以根据聚合物和增效剂的降解调整。此外，实现UL 94 V-0的必要载荷低于10％。

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