新型杂化磷腈的分子设计及其在航空电子电气无卤阻燃聚合物材料中的协效作用研究

Aircraft electrical and electronic devices have fire risk since the polymer materials may be ignited and cause fire under the circumstances such as equipment overheating, leakage, short circuit, aging, etc. For halogen-free flame retardancy of polymers, the common technology is to add large amount of inorganic flame retardants, which usually causes drop in mechanical properties and difficulty in processing. It is expected that organic-inorganic hybrid phosphazenes with both phosphorus and nitrogen can realize multiple synergistic effects through different functional groups. Therefore, for the breakthroughs in key technologies of halogen-free high-efficient flame retardance and the development of new fire-safety aircraft material, it is of great significance to design phosphazene hybrid derivatives which aim at the simultaneous improvements of mechanical performance, weather resistance and flame retardancy...The organic-inorganic hybrid structure of phosphazenes has direct impact on the processing, mechanical, thermal and combustible performances of polymer composites. Furthermore, the action mechanisms of phosphazenes in inorganic flame retardant filled materials are particularly relevant with the corresponding surface/interface properties. In this work, the surface/interface physical-chemical behaviours of hybrid phosphazenes will be studied in order to explore the effect of phosphazene substituents in typical polymer composites such as polypropylene and epoxy resin. Moreover, novel environmental-friendly hybrid phosphazenes will be designed, synthesized and applied. Their multi-synergistic mechanisms will be discussed on thermal degradation, combustion, rheological and mechanical behaviors, the main influencing factors will be determined, and the knowledge of key mechanism problems will be understood more in depth. In this way, the research will provide theoretical basis for the design, development and application of new environment-friendly flame retarded aircraft materials. .

飞机电子电气设备中的聚合物材料，易因设备过热、漏电、老化等被引燃而造成火灾。聚合物无卤阻燃技术普遍采用大量添加无机阻燃剂的方式，力学性能大幅度下降，严重影响加工；而含阻燃元素磷、氮的磷腈，通过特定官能团有望实现多重协效。因此，针对典型的航空电子电气无卤阻燃体系，开展杂化磷腈衍生物的分子设计和协效机理研究，在改善力学性能、耐候性的同时实现阻燃增效，对于聚合物高效无卤阻燃关键技术的突破和飞机防火安全新材料的开发具有重要意义。. 杂化磷腈在无机阻燃剂填充的聚合物体系中的作用机制，与磷腈的有机-无机杂化结构及其表面/界面行为有密不可分的关系。本项目拟研究磷腈官能团在聚丙烯、环氧树脂中的界面物理化学行为及影响规律，结合燃烧、热降解、力学及流变等数据，探讨杂化磷腈在阻燃体系中的多重协效作用机制，明确相关影响因素，深化对磷腈阻燃应用中关键机理问题的认识，为新材料的设计、开发与应用提供理论依据。

飞机电子电气设备中的聚合物材料，易因设备过热、漏电、老化等被引燃而造成火灾。为了满足飞机材料阻燃防火、低烟无毒的要求，常规的无卤阻燃技术因大量添加无机阻燃剂而导致材料的加工性能和综合应用性能大幅度下降。本项目正是针对典型的航空电子电气无卤阻燃体系，开展了一系列杂化磷腈衍生物的分子设计和协效机理的研究，选取聚丙烯绝缘材料和环氧树脂封装材料开展阻燃应用，最后实现了高效无卤阻燃，为飞机防火安全新材料的开发奠定了基础。. 在多尺度模拟计算的基础上，对磷腈衍生物官能团进行了筛选，最后设计合成了六-(4-羟基-2-丁炔氧基)环三磷腈（BYDCP）、六-(γ-氨丙基三乙氧基硅烷)（APESP）、六-(4-甲基苯硫基)环三磷腈（MPCP）和六-(4-甲基-2-吡啶氧基)环三磷腈（MPOCP），合成产物的结构通过红外、质谱和核磁进行了表征。采用热重-红外连用、X射线光电子能谱、氧指数、垂直燃烧、锥形量热仪、扫描电镜等对杂化磷腈在聚丙烯、硅橡胶、环氧树脂中的应用性能进行了测试、表征以及热分解、阻燃机理的研究，明确了杂化磷腈的作用机制，为新材料的设计、开发与应用提供了理论依据。. 研究发现，BYDCP、APESP、MPCP与传统的无机阻燃剂聚磷酸铵或三聚氰胺聚磷酸盐复配，一方面通过改善无机粒子和聚合物分子之间的表面/界面作用实现多相体系均匀分布分散，促进力学性能提升；一方面在燃烧/热降解过程中参与成炭反应，促进膨胀炭层表面的致密坚固，减少了烟气生成，氧指数和热释放有明显改善。特别是MPOCP，在燃烧受热时吡啶氧基团首先解离，产生的吡啶氧基等解离产物在气相有一定的淬灭效应，热解产生的小分子碎片同时促使聚合物基体提前分解产生大分子碎片，并相互作用生成粘度适中的凝聚相产物，与热解气相产物匹配最终形成内部致密多孔的炭层，充分发挥了凝聚相的隔绝阻燃作用；所以单独添加5%即可达到UL94的V-0级，抑烟和降低热释放的效果达40%以上。