The effects of nano- and molecularly-dispersed additives on the flame retardance in some chain-growth polymers containing covalently bound phosphorus

仅在英国，不受欢迎的火灾就造成数百人死亡(约600人死亡，1.6万人非致命伤亡)，每年约50亿人，给我们的行业和社会带来了巨大的损失。吸入烟雾和有毒气体占死亡人数的50%，烧伤占31%，其余的是与火灾有关的综合因素。其中许多死亡发生在与燃烧的聚合物材料有关的火灾中，这些火灾要么是火灾的主要来源，要么是火灾扩散的主要原因。显然，合成更具阻燃性的聚合物材料在减少未来此类死亡的规模方面发挥着重要作用。通过消防安全措施和不断上涨的保险费(估计占GDP的1%)而产生的无形成本是对经济的巨大消耗。此外，为了应对特定的威胁，如恐怖活动引起的火灾和公共建筑物的安全，有必要加深我们对不受欢迎的火灾行为的了解。该项目的总体目标是制备具有商业意义的聚甲基丙烯酸甲酯S、聚苯乙烯、聚丙烯腈和其他具有商业意义的链式反应聚合物，用含磷基团进行反应性改性，其物理和机械性能不会显著低于未改性的同类聚合物，但具有可调节的阻燃性能(凝聚相与气相)，以适合它们的应用，特别是在防火涂料、纺织品、粘合剂和热塑性模塑材料中。我们还建议分散纳米粘土，例如蒙脱石，在用含磷基团反应改性的聚合物中，目的是在燃烧过程中将阻燃部分在凝聚相中保留更长时间，从而改变汽相和凝聚相阻燃机理之间的平衡，有利于凝聚相。我们建议在阻燃聚合物中引入的另一种纳米添加剂是三聚氰胺。三聚氰胺起到了泡沫剂的作用，可以增强木炭作为燃烧障碍的有效性。我们还打算探索在改性聚合物中引入环糊精(CDS)的效果。硫化镉是环状低聚糖，像纤维素和其他多糖一样，是很好的成炭剂。我们相信，这是一条新的途径，将在方案的后期进行系统的探索，以确定在这些复合材料中运行的协同效应(如果有的话)。最后，将从对热解的气相产物的分析中获得关于机理的详细信息。这项研究的结果有望有助于在坚实的科学基础上制定新型防火材料。我们相信，在更广泛的意义上，这将导致更好的阻燃聚合物的方法。

Unwanted fires in the UK alone cost hundreds of lives (about 600 deaths and 16,000 non-fatal casualties) and about 5.0 billion per year, placing a huge drain on our industry and society. The inhalation of smoke and toxic gases accounted for 50% of the deaths, burns for a further 31%, and a combination of fire-related factors for the remainder. Many of these deaths occurred in fires in which burning polymer-based materials were implicated, either as the primary source of the fire or as a major contributor to the proliferation of the fire. Clearly, the synthesis of polymeric materials that are more flame-retardant has an important part to play in reducing the scale of such deaths in future.The invisible cost through fire safety measures and escalating insurance premiums (estimated as 1% of GDP) is a massive drain on the economy. In addition, in order to address specific threats, such as fire resulting from terrorist action and safety in public buildings, it is essential to develop our understanding of the behaviour of unwanted fires.The overall aim of the project is to prepare poly(methyl methacrylate)s, polystyrenes, polyacrylonitriles and other chain-reaction polymers of commercial significance, reactively modified with phosphorus-containing groups, having physical and mechanical properties not significantly inferior to those of the unmodified counterparts, but with tunable flame-retardance (condensed-phase vs. vapour-phase) to suit them for applications particularly in flame-retardant coatings, textiles, adhesives and thermoplastic moulding materials.We also propose to disperse nanoclays, such as montmorillonite, in polymers reactively modified with phosphorus-containing groups with the aim of retaining the flame retardant moieties longer in the condensed phase during combustion, thus altering the balance between vapour-phase and condensed-phase mechanisms of flame retardation in favour of the condensed phase. A further nanoscopic additive we propose to introduce into our flame-retarded polymers is melamine. Melamine acts as a spumific and can enhance the effectiveness of chars as barriers to combustion. We also intend to explore the effect of introducing cyclodextrins (CDs) into the modified polymers. CDs are cyclic oligomeric sugars and, like cellulose and other polysaccharides, are good char-forming agents. This, we believe, is a novel route which will be systematically explored during the latter part of the programme with a view to identifying the synergistic effects, if any, operating in these composite materials.Finally, detailed information on mechanisms will be obtained from analyses of the gas-phase products of pyrolysis. The results obtained from the study is expected to aid in formulating of novel fire-safe materials on a sound scientific base. This we beleive, in the broader sense, would lead to better ways of flame retarding polymers.