The influence of carbon fiber orientation on reaction‐to‐fire characteristics of layered polymer matrix composites is investigated in detail. M18‐1/G939 as woven fabric and M18‐1/G947 as unwoven roving prepregs with identical, epoxy based matrix composition were laid‐up to give 1 to 8 mm thick unidirectional and quasi‐isotropic laminates. Fundamental reaction‐to‐fire properties of these composites are interpreted on basis of the matrix components: epoxy resin and polyetherimide, as well as contained flame retardants magnesium hydroxide and zinc borate. Cone calorimetry and temperature distributions through the laminate show, that the velocity of combustion is influenced by fiber orientation for a given resin. For an unwoven roving it is confirmed that a quasi‐isotropic fiber orientation leads to faster ignition, due to preferred delaminations, but retards burning processes more effectively than a unidirectional lay‐up. This fundamental principle is extended to woven fabric reinforcements, however with less pronounced effects. Migration velocities of the pyrolysis zone are measured and additionally, decomposition of carbon fibers is considered. A comparison with a similar epoxy based matrix system without toughener and flame retardants: RTM6/G939 is carried out, in order to assess the effects by fiber orientation.

中文翻译：

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无纺粗纱和机织碳纤维增强材料对聚合物基复合材料反应燃烧性能的影响

详细研究了碳纤维取向对层状聚合物基复合材料反应-燃烧特性的影响。将M18-1 / G939做为机织织物，将M18-1 / G947做为无纺粗纱预浸料，它们具有相同的基于环氧树脂的基体成分，从而得到1至8 mm厚的单向和准各向同性层压板。这些复合材料的基本起火反应特性是基于以下基质成分进行解释的：环氧树脂和聚醚酰亚胺，以及所含的阻燃剂氢氧化镁和硼酸锌。锥形量热法和整个层压板的温度分布表明，对于给定的树脂，燃烧速度受纤维取向的影响。对于无纺粗纱，已经证实，由于具有较好的分层性，准各向同性的纤维取向可加快点火速度，但是比单向叠层更有效地延迟了燃烧过程。该基本原理扩展到机织织物增强材料，但是效果不明显。测量了热解区的迁移速度，此外，还考虑了碳纤维的分解。与不含增韧剂和阻燃剂的类似环氧树脂基基质体系进行了比较：RTM6 / G939，目的是通过纤维取向评估效果。