阻燃TPU炭层结构调控及其抑烟减毒机理研究

The generation of fire smoke is influenced by many factors, including the chemical composition and structure of polymer and flame retardant additives. The carbon layer formed by the interaction between polymer and flame retardant additives is effective of smoke suppression and toxicant reduction under combustion conditions. But, the formation process and structure adjustment of carbon layer is not known; and the suppression mechanism for smoke and toxicant is also unclear. In this project, flame retardant thermoplastic polyurethane elastomer (TPU) is selected as the research object. The dynamic structure evolution of condensed phase, and the emission concentration, chemical composition and physical form of fire smoke will be investigated in the combustion process of flame retardant TPU. The evolution process of solid phase will be adjusted by optimizing flame retardants and synergistic agent system during the combustion process of flame retardant TPU. Then, the structure and thermal properties of carbon layer will be studied, which will be used to analyze its impact on the fire smoke generation process. The size effect on the thermal degradation characteristics of flame retardant TPU will be studied and a thermal degradation model will be established based on molecular scale. The essential relations will be established among the formation process of carbon layer, the characteristics of ignition and heat release, the composition and formation process of fire smoke components. Combining with the thermal degradation process of flame retardant TPU, the smoke suppression and toxicant reduction mechanism will be revealed for carbonization flame retardant TPU, which will lay a solid theoretical foundation for the prevention and control of fire smoke.

聚合物材料火灾烟气的生成受到很多因素的影响，其中包括聚合物和阻燃添加剂的化学组成、结构。燃烧条件下，由聚合物和阻燃添加剂之间发生相互作用而生成良好结构的炭层是实现抑烟减毒的有效手段之一，但炭层的生成过程与结构调节以及抑烟减毒作用机制还不清楚。本项目以阻燃热塑性聚氨酯弹性体（TPU）为研究对象，研究阻燃TPU在燃烧过程中凝聚相结构动力学演变规律，火灾烟气的排放浓度、化学组成和物理形态；优化阻燃剂-协效剂体系，调控阻燃TPU在燃烧过程中的凝聚相结构演变历程，并研究其对炭层组成结构与热物理特性的影响规律，进一步分析其对火灾烟气生成过程的影响；研究尺寸效应对阻燃TPU热降解特性的影响，建立基于分子尺度的热降解模型；建立燃烧过程中炭层的生成过程、点燃与释热特性、火灾烟气组分及生成过程之间的本质关联，结合阻燃TPU的热降解历程，揭示炭化阻燃TPU抑烟减毒机制，为火灾烟气防治奠定坚实的理论基础。

针对传统阻燃热塑性聚氨酯弹性体（TPU）在燃烧过程中火灾烟气量和毒性难以抑制的难题，利用功能化碳球（空心球）、柠檬酸（镍、钴、铜）、金属有机骨架化合物、壳聚糖及其组合物、铜-水杨醛螯合物、离子液体、富马酸（盐）、功能化芳纶纤维等调控阻燃 TPU 在燃烧过程中的凝聚相结构，并通过研究其阻燃和抑烟减毒性能，揭示其抑烟减毒机理。同时，为其它高分子材料在火灾过程中的烟气防治提供了一种新思路。研究结果表明：⑴ 采用1-乙酸乙酯基-3-甲基咪唑六氟磷酸盐（[EOOEMIm][PF6]）、1-乙酸乙酯基-3-甲基咪唑四氟硼酸盐（[EOOEMIm][BF4]）改性空心玻璃微珠和分子筛能够显著提高空心玻璃微珠和分子筛在TPU基体中的分散水平、界面结合力，进而协同调控阻燃TPU的凝聚相结构，发挥很好的阻燃和抑烟减毒作用；⑵ 柠檬酸（镍、钴、铜）、金属有机骨架化合物、壳聚糖、铜-水杨醛螯合物能够显著提高聚磷酸铵（APP）在TPU基体中的分散水平，并通过凝聚相和气相的协同作用，显著降低APP阻燃TPU复合材料在燃烧过程中的火灾烟气生成量；⑶ 为了进一步提高TPU的阻燃和抑烟减毒性能，利用添加剂与TPU分子链之间的氢键、π-π堆积等作用，实现了富马酸（盐）、功能化芳纶纤维在TPU基体树脂的均匀分散，提高了TPU复合材料的热稳定性能和阻燃性能，改善了炭层结构，有效抑制了TPU复合材料在燃烧过程中的火灾烟气的生成。