功能化蒙脱土对IFR/SEBS燃烧行为的全过程协同控制与作用机理

Styrenic thermoplastic elastomer SEBS is widely used in various applications. However, the ethylene-butene and styrene segments in SEBS are extremely flammable, which limits wider applications of SEBS and its blends. In this proposal, we aim at developing a novel halogen-free flame retardant with structure tailor at nano-scale, using an novel organo-functionalized montmorillonite (i.e. organo-clay) in combination with an Intumescent Flame Retardant (IFR), based on mechanistic understanding and manipulation on each individual steps in combustion of the SEBS. The organo-clay will be prepared by first intercalation using an organophosphate micelle and then grafting using an appropriate coupling agent. The novel flame retarding nano-system is expected to function from suppressing the flame ignition, diluting the flammable gas, encapsulating the flammable material to strengthening the burning melt. By a delicate control in micro-structure and morphology, we hope to uniformly disperse the montmorillonite platelets in the SEBS matrix to maximize barrier efficiency of the clay, while not seriously deteriorating other properties (e.g. melt viscosity, elongation at break, viscoelasticity) of the SEBS composite. The interplay between the combustion behavior, the morphology and the interfacial interaction within the organo-clay/IFR/SEBS system will be systematically investigated, in order to clarify function mechanism of the novel flame retardant. The outcome of the project will be beneficial for development and applications of other halogen-free flame retarded styrenic thermoplastic elastomers. No doubt, realization of this project contributes to further progress in the flame retardant technology and has significant social impact in reducing the fire accident.

苯乙烯类热塑性弹性体SEBS具有广泛的应用领域，但其分子链中乙烯-丁烯链段和苯乙烯链段都极易燃烧，使SEBS及其共混物具有火灾隐患。本研究根据SEBS的燃烧和热分解特点，采用磷酸酯微胶束插层和偶联剂接枝改性制备功能化有机蒙脱土，通过协同膨胀型阻燃剂(IFR)，发展一种集抑制、稀释、覆盖、增强效应于一体的新型纳米无卤阻燃体系，实现对SEBS热塑性弹性体燃烧行为的全过程控制。通过调控纳米阻燃体系的微观结构，使功能化蒙脱土均匀分散并插层于SEBS嵌段共聚物中，在利用蒙脱土片层阻隔发挥协同阻燃作用的同时，并不导致SEBS的使用性能（熔体粘度、断裂伸长率、粘弹性等）发生显著恶化。本项目将探索功能化蒙脱土与IFR/SEBS的界面相互作用与材料燃烧行为之间的关系，阐明阻燃机理。项目的研究成果将为无卤阻燃苯乙烯类热塑性弹性体材料的应用和发展奠定基础，对拓展阻燃技术领域以及减少火灾事故发生有重要的现实意义。

苯乙烯类热塑性弹性体SEBS具有广泛的应用领域，但极易燃烧且燃烧时产生大量熔滴，使SEBS及其共混物具有火灾隐患。本项目在分析了膨胀型阻燃SEBS的燃烧全过程和热分解机理的基础上，分别采用硅烷偶联剂对季鏻盐插层蒙脱土进行再次改性，以及磷酸酯胶束插层改性制备了功能化蒙脱土，实现凝聚相和气相对膨胀阻燃SEBS的全过程协同阻燃。形成了集协效阻燃、增强增柔以及抗水解等效应于一体的新型多功能纳米阻燃体系，并采用熔融共混的方式制备了具有良好阻燃效果和物理性能的无卤膨胀阻燃SEBS纳米复合材料。通过对功能化蒙脱土在SEBS复合材料中的分散状态、界面作用，以及对SEBS微相分离结构的影响，探究了功能化蒙脱土对SEBS复合材料总体性能提升的关键要素。阐释了无卤膨胀阻燃SEBS纳米复合材料的多相结构与阻燃机理的关系。项目的研究成果为热塑性弹性体的无卤阻燃及材料性能提升和发展奠定了理论与物质基础，对拓展阻燃技术领域以及提高社会生产和生活的安全具有重要的学术和现实意义。