Preparation and performance of highly conductive polypyrrole-modified basalt fiber

Basalt fibers (BF) possess outstanding mechanical properties, corrosion resistance, and thermal stability, making them widely utilized in various sectors of the national economy. However, due to the insulating nature of basalt fibers, their application in areas such as electromagnetic shielding and electrostatic protection is limited. The investigation introduces a method for preparing conductive basalt fibers, which not only enhances the conductivity of basalt fibers but also improves the tensile strength. It is an efficient, low-cost, and environmentally friendly preparation method. The method utilizes pyrrole monomers (Py), iron chloride oxidant (FeCl₃), and the dopant sodium 5-sulfosalicylate (NaSSA) as raw materials. Conductive polypyrrole (PPy) is deposited on the surface of basalt fibers through in-situ polymerization. Different concentrations of Py, FeCl₃, and NaSSA are investigated as parameters to study their effects on the conductivity of basalt fibers. Through the in-situ polymerization method, basalt fibers gradually change from brown to black, with a uniform, stable, and thick polypyrrole coating on the surface. The polypyrrole particles exhibit a high doping level, bipolaron ratio, and conjugated chain length, indicating a well-defined structure. In terms of electrical conductivity, the resistance of polypyrrole-modified basalt fibers decreases to a minimum of 8 × 10⁻³ Ω·cm, demonstrating excellent conductivity after modification. In terms of mechanical properties, the tensile strength of the fibers is maximally increased by 20.6%, highlighting the significant advantages of the method in preserving fiber structure and enhancing fiber mechanical performance. It was verified by variability analysis and Weibull distribution modeling. The investigation provides a new opportunity for expanding the application of basalt fibers and achieving functionalized basalt fiber composite materials.