Thermoplastic composites were prepared by melt pressing fabrics from commingled natural (flax) –thermoplastic (polypropylene (PP) and polylactic acid (PLA)) polymeric fibres. Fabrics were treated with a number of commercial flame retardants (FRs) used for textiles prior to composite preparation. Their flammabilities and mechanical performances have been evaluated in terms of FR types effective on each fibre type. The fire performances of the composite laminates evaluated using UL-94 showed that flax/PP control and all flame retarded composite samples failed the UL-94 test, except for one treated with organophosphonate FR. On the other hand all flame retarded flax/PLA samples achieved V0 rating. Cone calorimetric results obtained at 35 kW/m² also showed that all FRs significantly reduced the flammability of the composites and that their efficiencies were more pronounced in flax/PLA than in flax/PP composites. The mechanical performances of composites evaluated in tensile, flexural and impact modes indicated that all flame retardants reduced the mechanical properties of the composites, with the extent of reduction dependent on the pH of the flame retardant solution used. The reduction in mechanical properties was more severe in flax/PLA composites than in flax/PP composites.

热塑性复合材料是通过将混合的天然（亚麻）-热塑性（聚丙烯（PP）和聚乳酸（PLA））聚合物纤维熔融压制而成的。在复合材料制备之前，用许多用于纺织品的商业阻燃剂（FR）处理织物。已经根据对每种纤维类型有效的FR类型对它们的可燃性和机械性能进行了评估。使用UL-94评估的复合材料层压板的防火性能表明，亚麻/ PP对照品和所有阻燃复合材料样品均未通过UL-94测试，但其中一种经过有机膦酸酯FR处理。另一方面，所有阻燃亚麻/ PLA样品均达到V0等级。在35 kW / m ^2下获得的锥体量热结果还表明，所有阻燃剂均显着降低了复合材料的可燃性，并且其效率在亚麻/聚乳酸中比在亚麻/聚丙烯复合物中更为显着。以拉伸，弯曲和冲击模式评估的复合材料的机械性能表明，所有阻燃剂均会降低复合材料的机械性能，降低的程度取决于所用阻燃剂溶液的pH值。与亚麻/ PP复合材料相比，亚麻/ PLA复合材料的机械性能下降更为严重。