聚乳酸/烷基次膦酸盐复合材料的性能、阻燃机理以及烟气毒性研究

With the exhaustion of oil resource and the deterioration of ecological environment, bio-based polymers have received more and more attraction, especially polylactic acid (PLA). PLA possesses excellent comprehensive properties; however, its high flammability limits the further application of PLA. Due to the disadvantage of inorganic hypophosphite salt and very few reports about smoke toxicity of the materials during combustion, flame retardant synthesis technology is combined with static state tube furnace (SSTF) in this project. A series of alkyl phosphinate salts was synthesized, and the effect of these alkyl phosphinate salts on the flame retardancy, mechanical, crystallization, and thermal properties of PLA composites will be investigated. The relationship between the components and properties of the materials will be discussed to obtain PLA composites with excellent comprehensive properties. The change in gas and condensed phase during pyrolysis and combustion of PLA/alkyl phosphinate salt composites will also be investigated to find out the char formation mechanism and flame retardant mechanism. Static state tube furnace is applied to study the change of evolved smoke and gases, and quantitatively evaluate the fire toxicity of the materials, get the non-heat hazard parameters of the materials. Combination of the heat hazard and non-heat hazard parameters will build the integral fire hazard evaluation of the material. The implementation of the project can lay a theoretical and experimental basis for the development of novel flame retardant bio-based polymer composites and evaluation of the smoke toxicity of the materials during combustion.

随着石油资源的枯竭以及以生态环境恶化，生物基聚合物日益受到人类重视。其中聚乳酸以其卓越的综合性能而备受关注，但是其易燃的缺点限制了其应用。本项目针对目前无机次磷酸盐阻燃剂存在的问题以及阻燃材料烟气毒性研究不足的现状，从分子设计角度出发，将阻燃剂合成技术与稳态管式炉烟气毒性试验平台进行结合，合成一系列烷基次膦酸盐阻燃剂，研究其对聚乳酸的阻燃、力学、结晶和热性能的影响，探索材料的组成、结构和性能之间的内在联系，制备具有优异综合性能的聚乳酸复合材料；研究材料在热解和燃烧过程中的气相和凝聚相的变化规律，揭示其成炭机制和阻燃机理；采用稳态管式炉烟气毒性试验平台研究材料燃烧过程中烟气毒性的产生规律，并对其烟气毒性进行定量评价，获得材料非热危害相关参数；结合材料热危害研究，建立完整的材料火灾危害性评价体系。该项目的实施能够为生物基聚合物阻燃复合材料的开发以及材料燃烧过程中烟气毒性评价奠定理论和实验基础。

随着石油资源的枯竭以及以生态环境恶化，生物基聚合物日益受到人类重视。其中聚乳酸以其卓越的综合性能而备受关注，但是其易燃的缺点限制了其应用。本项目针对无机次磷酸盐阻燃剂存在的问题，制备了二乙基次膦酸铝、苯基次磷酸铝、苯基次膦酸锌、苯基次膦酸镧、苯基次膦酸铈五种有机次膦酸盐，并研究其对聚乳酸阻燃性能、热稳定性、燃烧性能的影响，探索材料组成、结构和性能之间的内在联系，在此基础上揭示次膦酸盐的成炭机制和阻燃机制。.研究表明二乙基次膦酸铝阻燃效果良好，30wt%二乙基次膦酸铝使得聚乳酸复合材料达到UL-94V-0级别，极限氧指数为31.6vol%,热释放速率峰值下降37.1%。苯基次膦酸铝阻燃效果良好，30wt%苯基次膦酸铝使得聚乳酸复合材料达到UL-94 V-0级别，极限氧指数达到25.6vol%,此外，苯基次膦酸铝使得复合材料热稳定性和成炭率有明显提高。苯基次膦酸锌可以使得复合材料热分解温度提高4-8℃，同时可以明显降低复合材料总热释放。30wt%苯基次膦酸镧添加量仅能使聚乳酸达到UL-94 V-2级别，但热释放速率峰值和总热释放分别下降31.9%和48.1%，同时发现苯基次膦酸镧可以提高复合材料热稳定性。苯基次膦酸铈仅能使得聚乳酸复合材料达到UL-94V-2级别，但可以明显提高复合材料热稳定性，20wt%苯基次膦酸铈使得复合材料热释放速率峰值和总热释放分别下降13.9%和28.0%。.通过研究可以发现，磷含量和金属阳离子对聚乳酸阻燃效果影响显著，稀土金属阳离子的存在可以提高复合材料热稳定性，并有效降低热释放速率峰值和总热释放。本项目的顺利开展为新型生物基聚合物复合材料的开发提供一定的理论基础和实验基础。