层状纳米填料对膨胀型透明防火涂料的透光、阻燃和抑烟性能的调控及其机理研究

Investigation on the synergistic effect between nano-filler and intumescent flame retardant is considered as one of the current research focuses in the field of flame-retardant materials. However, nano-filler remains not to effectively solve the bottleneck problem that it cannot impart both excellent optical transparency and flame retardancy to transparent intumescent fire-retardant coatings due to the light scattering of nano-filler in the polymer matrix. Based on the theory of molecule design, flexible phosphate ester was intercalated into the interlayer space of layered nano-filler to synthesize a series of novel nano-filler hybridized phosphate ester flame retardants via the reaction characteristics of nano-layers in this project. Then, the obtained flame retardants were mixed with amino resin to produce transparent intumescent fire-retardant coatings with optimized optical transparency, flame retardancy and smoke suppression properties via the design, construction and adjustment of the flame retardants. The effects of phosphate ester structure and nanoparticle dispersion on the optical transparency, flame retardancy and smoke suppression properties of transparent intumescent fire-retardant coatings were analyzed. Based on the theories and technologies of fire science, materials science and optics, the influences of structure and composition of transparent intumescent fire-retardant coatings on the optical transparency, flame retardancy and smoke suppression properties were researched and the optical transparency mechanism was clarified. Furthermore, the influences of the structure and composition of transparent coatings on the thermal degradation, combustion behavior and the generation and evolution rules of the charred layer were analyzed and the relationship between the structure and properties of the coatings was clarified. Based on the above results, the synergistic flame-retardant and smoke suppression mechanisms of layered nano-filler in the transparent intumescent fire-retardant coatings were proposed. The research will establish the theoretical and experimental foundation for the preparation and application of high performance transparent intumescent fire-retardant coatings.

纳米填料协同膨胀阻燃体系是当前阻燃领域的研究热点之一，但纳米填料易造成光散射现象而导致涂层透光率下降，使纳米填料协同膨胀型透明防火涂料面临难以同时兼具高阻燃和高透明性的技术瓶颈和难点。针对这一难题，本项目从分子结构设计出发，利用层状纳米填料的层间反应特性将柔性磷酸酯插入纳米片层间制备纳米复合阻燃剂，通过工艺优化和结构调控制备高性能膨胀型透明防火涂料。从火灾学、材料学和光学角度出发，研究柔性磷酸酯结构与层状填料的分散状态及结构等对涂层透光、阻燃和抑烟性能的影响，阐明透明涂层的结构、组成与其性能之间的内在关系；探讨层状纳米填料对涂层透明性能的影响机制，揭示涂层的透光机理；研究透明涂层的结构、组成与其热解与燃烧过程以及炭层的结构、组成与形成机制之间的关系，揭示层状纳米填料的协同阻燃和抑烟作用机制。该研究有望为高透明、低烟和高阻燃性膨胀型透明防火涂料的制备和应用奠定一定的理论和实验基础。

本项目面向历史文物建筑火灾防治的重大需求，针对膨胀型透明防火涂料难以同时满足装饰性和防火性的难题，结合分子结构设计、纳米技术和协效增强的原理和方法设计合成了一系列兼具装饰、阻燃、抑烟和耐候功能的一体化膨胀型透明防火涂料。系统研究了氧化石墨烯、层状硅酸盐和纳米金属粒子等三类典型纳米填料复合柔性磷酸酯的结构组成对膨胀型透明防火涂料理化、阻燃、抑烟、成炭和抗老化性能的影响和规律，阐明了纳米填料分布情况、添加量与涂层性能之间的关系，揭示了典型纳米填料在透明防火涂料中的透光、阻燃与抑烟作用机理。研究取得的主要进展和成果包括：（1）利用聚乙二醇硼酸酯（PEG-BA）改性磷酸酯可以提升膨胀型透明防火涂料的柔韧性、阻燃、成炭和抗老化性能，而PEG-BA在透明涂层中的协效效率与其分子量和添加量密切相关，其中PEG200-BA相比于PEG400-BA、PEG600-BA和PEG800-BA具有更优的协效作用。（2）通过化学改性方法可使层状硅酸盐（高岭土、滑石粉和云母粉）均匀分布在膨胀型透明防火涂料基材中以保持涂层的高透光率，其中均匀分布的层状硅酸盐还能有效增强涂层的附着力、热稳定性、阻燃、抑烟、成炭和抗老化性能，表现出较好的协效阻燃和抑烟作用。（3）利用氧化石墨烯的层间反应特性制备了氧化石墨烯纳米复合柔性磷酸酯阻燃剂，实现了氧化石墨烯片层在膨胀型透明防火涂料中的均匀分布，进而在保持涂层高透光率的同时有效增强涂层的附着力、热稳定性、阻燃、抑烟和成炭性能。（4）为了进一步提高透明涂层的耐候性和抑菌性，利用表面改性和化学接枝方法将纳米二氧化钛引入柔性磷酸酯阻燃剂，进而制备了兼具装饰、抗菌、防火和耐候等功能于一体的膨胀型透明防火涂料，并揭示了纳米二氧化钛在透明涂层中透光、抗菌、阻燃和抑烟作用机理。本项目为制备装饰、防火、抑烟和耐候多功能一体化膨胀型透明防火涂料提供了理论依据和实验基础，对提升文物建筑火安全性具有重要的意义。