石墨烯表面纳米MoO3、有机磷双功能化改性及其不饱和聚酯纳米复合材料的阻燃抑烟性能与机理研究

Unsaturated polyester resin has very poor resistance to fire and high release of heat and toxic gases smoke yielding from combustion, which needs to be modified by flame retardancy and smoke suppression. Aiming at overcome the current shortcomings of the present study of smoke suppression modification for UPR, and the limitation of the smoke toxicity assessment, nano-MoO3 and organic phosphorus dual functional modified graphene and some heat resistant, reactive-type flame retardant monomers are synthesized and incorporated into UPR. Through optimizing the experimental conditions, flame retardant UPR/functionalized graphene nanocomposites with excellent fire resistance and low toxic gases and smoke are obtained. The effect of flame retardant monomers and functionalized graphene on the flame retardant, combustion and mechanical properties of UPR nanocomposites is investigated to establish the internal relationship between the micro-structure and macro-performance. Thereafter, the fire risk of UPR nanocomposites are evaluated through simulating the different stages of combustion development under the control of combustion temperature and oxygen concentration based on the steady-state tube furnace toxicity test platform. Moreover, investigating the influence of nano-MoO3, functionalized graphene and flame retardant monomer on the production law and toxicity of smoke in different combustion stages combined with the study on the variation of the composition and structure，formation mechanism of the gas and condensed phase products in the process of pyrolysis and combustion of UPR nanocomposites, in order to reveal flame retardant, smoke suppression and reduced toxicity mechanism. The implementation of this project will pave the way for the theoretical and experimental basics for the design and preparation of flame retardant UPR nanocomposites with the outstanding flame retardancy, low toxicity and low smoke density.

不饱和聚酯（UPR）存在较高的易燃性，且燃烧过程中释放大量热量和有毒烟气，因此需要对其进行阻燃和抑烟改性，而当前UPR的研究以阻燃改性为主。本项目针对UPR抑烟改性研究的不足和烟气毒性评价的局限，设计合成纳米MoO3、有机磷改性的阻燃、抑烟双功能化石墨烯及耐热反应型阻燃单体，制备低烟、低毒的阻燃UPR/功能化石墨烯纳米复合材料。通过研究不同结构的阻燃单体、功能化石墨烯，对材料阻燃、燃烧和力学性能的影响，建立材料宏观性能与微观结构间的构效关系；发展稳态管式炉试验平台，通过调控燃烧温度和氧气消耗，模拟材料燃烧发展的不同阶段，重点研究纳米MoO3、功能化石墨烯、阻燃单体，对材料燃烧不同阶段烟气生成规律及毒性的影响，结合对材料热分解及燃烧过程中气相、凝聚相产物组成、结构及生成规律的研究，揭示材料阻燃、抑烟减毒的机理，为制备低烟、低毒的阻燃UPR纳米复合材料提供理论依据和实验基础。

项目针对不饱和聚酯存在高易燃性的缺点，制备阻燃剂FR-1，与APP复配组成膨胀阻燃剂；同时制备了含有丙烯酸双键FR-2和马来酰亚胺结构的反应型阻燃单体FR-3、FR-4、FR-5；用阻燃低聚物FR-6功能化修饰石墨烯，并与FR-2和TAIC复配使用，制备了一系列阻燃UPR复合材料。研究发现阻燃UPR复合材料的热稳定性和高温热解成炭量得到提高，LOI值从22.0%提高到28.0%，热释放速率峰值和总热释放量分别降低了33%和15%，引入阻燃功能化石墨烯之后，PHRR和THR进一步分别降低了48%和35%，揭示了阻燃UPR复合材料具有优异的阻燃性能。通过实时红外及阻燃UPR热解炭层的形貌分析，揭示了含有机磷的阻燃剂主要通过促进基体热解成炭，发挥凝聚相阻燃机理，而阻燃功能化石墨烯起到协同阻燃和片层阻隔作用，从而使得UPR的阻燃性能得到提高。. 此外，根据企业需求，针对聚合物基食品包装材料的存在力学性能和阻隔性能差的缺点，影响食品的保质期等问题，通过干式复合工艺，将石墨烯引入至复合薄膜的聚氨酯粘合剂中，制备了石墨烯基高阻隔食品包装薄膜材料。通过性能研究发现，引入占粘合剂聚氨酯固含量0.2wt%的石墨烯后，BOPP/CPP复合薄膜的氧气透过率降低了52.7%，水蒸气透过率降低了45.5%，复合薄膜的剥离强度提高了200%，且石墨烯基复合薄膜的相对透光率为95.6%，对样品的透明性无影响；阻隔性能提高的主要归因于石墨烯在聚氨酯中的良好分散，通过石墨烯纳米片层的阻隔效应和多路径渗透效应，阻止了气体分子的扩散，从而提高了阻隔性能。. 通过项目的研究，开发了多种阻燃UPR复合材料体系，其中含马来酰亚胺结构的反应型阻燃单体，通过苯环结构的引入，提高了基体的耐热性能和初始热稳定性能，克服了传统有机磷阻燃剂存在的初始热稳定性低，添加量高的缺点，为新型反应型无卤阻燃不饱和聚酯的开发提供了理论依据和实验基础；而基于干式复合工艺的石墨烯基高阻隔食品包装薄膜的制备，创造性将石墨烯分散在聚氨酯粘合剂中，解决了石墨烯基纳米复合材料的关键分散性问题，实现了石墨烯在食品包装领域的产业化应用。