The development of a new type of sustainable flame retarded polyamide 6 (PA6)-based composites, modified with biocarbon/phosphorus flame retardant/basalt fiber system (BC/OP/BF). The evaluation of the material performance and flammability

• Biocarbon-based flame retarded filler system was applied in polyamide. • Flammability of prepared injection molded parts was strongly reduced. • Basalt fiber reinforcement additionally improved the heat resistance. • BC/OP/BF mixture offers a good balance of mechanical performance and flame retardancy. The presented study was focused on the development of a sustainable type of composite characterized by improved flame retardance. Polyamide 6 (PA6) was modified with the addition of biocarbon (BC) and organic phosphorous flame retardant (OP). The initial part of the study was aimed at the evaluation of the OP:BC system efficiency, while the final part of the research focuses on the preparation of composites with basalt fibers (BF) reinforcement. Composite materials were modified using 20% of the OP:BC mixture at different ratios. The reinforced samples were modified with an additional 20% of the BF filler. Prepared samples were subjected to detailed analysis, mechanical properties evaluation, thermal analysis, microscopic observations, and burning tests. The results indicate that the application of the developed concept led to a large decrease in flammability for most of the investigated PA6-based materials; however, the most interesting results refer to materials containing a balanced OP:BC system.