Exploring the reinforcement and conductivity mechanism of K₂FeO₄‐modified multiwalled carbon nanotubes in carbon black/natural rubber composites

Abstract

This study employs potassium ferrate (K2FeO4) for the oxidation treatment of multi‐walled carbon nanotubes (MWNTs) under neutral and acidic conditions. A wet flash evaporation process is utilized to prepare natural rubber/MWNTs/carbon black composites, enhancing the performance of rubber composites. The increased oxidation level of MWNTs enhances their hydrophilicity, increases the quantity of oxygen‐containing hydroxyl groups on the surface, promotes dispersion within the natural rubber matrix, and ultimately improves the performance of the rubber products. The effective dispersion of MWNTs reduces electron transport resistance, forming a favorable electron transport channel in natural rubber. Experimental results indicate that K2FeO4 achieves the highest oxidation degree and optimal performance in an acidic environment. Compared to untreated MWNTs rubber composites, the oxidized MWNTs rubber composites exhibit a 34.9% reduction in the Payne effect, a 15.7% decrease in wear, a 12.7% reduction in rolling resistance, and a two‐order‐of‐magnitude increase in conductivity. This study provides a novel approach for preparing water‐dispersible MWNTs and high‐performance rubber composites, holding potential applications in premium rubber products and conductive rubber fields.Highlights The wet flash refining process improved the dispersion of MWNTs. K2FeO4 oxidation of MWNTs was enhanced under acidic conditions. Oxidized MWNTs combined with CB to form a CB‐MWNTs‐CB filler network. Oxidized MWNTs and CB increased the “ball‐chain” arrangement in NR.