Mechanical properties, flame retardancy, and thermal stability of basalt fiber reinforced polypropylene composites

In this article, the mechanical properties, flame retardancy, and thermal stability of basalt fiber reinforced polypropylene composites (BFRPPs) and polypropylene (PP) were investigated and compared. The combustion performance and thermal stability of BFRPPs and PP were evaluated by limiting oxygen index (LOI) test, cone calorimeter test (CCT), and thermogravimetric analysis (TGA). The results showed that basalt fibers could enhance mechanical properties, flame retardancy, and thermal stability of PP. With the increase of basalt fiber content, the strength and stiffness of BFRPPs increased significantly, and the elongation decreased obviously. Adding basalt fibers into PP could improve the LOI value. BFRPPs burned appreciably more slowly than PP under the same oxygen concentration. Simultaneously, BFRPPs indicated a better anti-melt dripping effect than PP matrix. The heat release rate (HRR), total heat release (THR), rate of smoke release (RSR), and total smoke release (TSR) of BFRPPs decreased compared to PP matrix. Moreover, the addition of basalt fibers to PP could contribute to the formation of a more compact and continuous char layer, which effectively reduced the transfer of heat and oxygen, resulting in a better flame retardancy of BFRPPs.