Novel co-blended polymer matrix systems for fire resistant structural marine composites

由于其特殊的强度和刚度特性，纤维增强复合材料在船舶、汽车和铁路运输行业的各种承重结构中的应用越来越多。这些复合材料，特别是玻璃增强聚合物复合材料的一个严重问题是，它们支持燃烧，并且在火灾条件下燃烧，通常会产生大量烟尘和烟雾。玻璃增强聚合物复合材料在海洋和其他地面运输应用中最为普遍。绝缘材料可以减少火灾危险，但不能消除火灾危险。此外，绝缘材料增加了重量和成本。该复合材料的可燃部分为有机树脂基体。最常见的阻燃树脂和整体复合材料的方法是通过在聚合物骨架中添加阻燃元素或在树脂中使用阻燃添加剂对树脂进行物理和化学改性。对于聚酯或乙烯基酯树脂，通常使用卤化化学品。虽然卤素的存在大大降低了树脂的可燃性，但由于环保意识的提高和严格的环保法规，含卤素阻燃剂正在受到严格的审查。当使用无卤阻燃剂时，总是需要大量（约30% w/w）才能达到要求的阻燃水平。然而，高浓度的添加剂会降低复合材料的力学性能。此外，它们也影响树脂的可加工性树脂转移成型技术，通常用于这些类型的复合材料。我们在此建议通过与固有阻燃树脂（如酚醛树脂或三聚氰胺甲醛树脂）共混来降低乙烯酯和/或聚酯树脂的可燃性，从而逐步改变树脂基体。该提案是由博尔顿大学的“防火材料”小组和南安普顿大学的“流体结构相互作用研究小组”（FSIRG）共同尝试开发、构建、测试和模拟新型阻燃复合材料，最初用于船舶应用。主要重点是开发一种改性聚合物基体，通过与适当改性的酚醛树脂和三聚氰胺树脂混合，降低乙烯基酯或聚酯树脂的可燃性，这将增加基体的热稳定性和成焦能力。改性树脂的物理和化学性能将得到优化，以实现：(a)树脂不熔成型，从而获得良好的加工能力；(b)低温固化能力，以最大限度地提高与玻璃纤维的相容性和粘合性；(c)扩大规模以生产大型层压板和结构。建议采用两种不同的方法：第一种是以“材料”为基础的，主要由博尔顿设计；另一种是以“结构”为基础的，博尔顿和南安普顿都将为此做出贡献。具体任务包括树脂混合，树脂的化学/物理改性，工艺建模和树脂注入，复合层压板制备和可燃性评估。由此生产的复合层压板和结构预计将符合《国际海上人命安全公约》（SOLAS）中IMO/HSC规则（国际海事组织高速船舶安全规则）的防火性能要求。此外，复合材料的结构性能有望与目前的玻璃/乙烯基酯相当。我们还建议从结构设计的角度进行防火性能建模、力学表征和渐进损伤分析。我们希望这些复合材料也能在其他工程领域找到应用，因为这些领域越来越多地寻求低重量、耐热和阻燃结构。

Fibre-reinforced composites are finding increased usage in load-bearing structures in a variety of applications in marine, automotive and rail transport industries owing to their specific strength and stiffness properties. A serious problem with these composite materials, particularly glass-reinforced polymeric composites, which are the most prevalent in marine and other surface transport applications, is that they support combustion and in fire conditions burn, most often with heavy soot and smoke. Insulation can reduce the fire hazard, but does not eliminate it. Moreover the insulation adds weight and cost to apply.The combustible part of the composite is organic resin matrix. Most common method of fire retarding the resin and hence, the overall composite is the physical and chemical modification of the resin by either adding fire retardant element in the polymer backbone or using fire retardant additives in the resin. For polyester or vinyl ester resins, usually halogenated chemicals are used. While the presence of halogen significantly reduces the flammability of the resin, due to increasing environmental awareness and strict environmental legislations thereof, halogen - containing fire retardants are being strictly scrutinised. When non-halogen flame retardants are used, invariably they are required in large quantities (>30% w/w) to achieve required level of fire retardancy. The high concentrations of additives however, can reduce the mechanical properties of the composite. Moreover, they also affect resin's processability for resin transfer moulding technique, commonly used for these types of composites. We propose here a step change in the resin matrix by reducing the combustibility of vinyl ester and/or polyester resin by co-blending with inherently fire retardant resins, such as phenolic or melamine-formaldehyde resin.This proposal is a joint attempt by 'Fire Materials' group at the University of Bolton and 'Fluid Structure Interactions Research Group (FSIRG) at the University of Southampton to develop, construct, test and model novel, fire-retardant composites, initially for marine applications. The principal focus is to develop a modified polymeric matrix to reduce the combustibility of the vinyl ester or polyester resins by blending with appropriately modified phenolic and melamine resins, which will increase the thermal stability and char-forming capacity of the matrix. The physical and chemical properties of the modified resin will be optimised to enable: (a) the resin to be infusible for moulding leading to good processing ability: (b) low temperature cure capability to maximize compatibility and bonding with glass fibres; and (c) up-scaling to produce large laminates and structures. It is proposed that two different approaches will be taken: the first one 'Material' based, mainly by Bolton, and the other 'Structure' based, to which both Bolton and Southampton will contribute. The specific tasks include resin blending, chemical / physical modification of the resin, process modelling and resin infusion, composite laminate preparation and flammability evaluation. The composite laminates and structures thus produced are expected to comply with the fire performance requirements contained in the International Convention for the Safety of Life at Sea (SOLAS) as `IMO/HSC Code (Code of Safety for High Speed craft of the International Maritime Organisation). Additionally, the structural performance of the composite would be expected to be comparable with current glass/vinyl ester. We also propose to conduct fire performance modelling, mechanical characterisation and progressive damage analysis from a structural design viewpoint.We expect these composites to find applications also in other engineering arenas for which low-weight, thermally resistant and fire-retardant structures are increasingly being sought.