Improving the mechanical properties and high‐temperature, high‐pressure corrosion resistance of basalt fiber/epoxy composites via fiber surface modification with silicon nanowires and waterborne polyurethane

Abstract Although basalt fiber reinforced polymer composites (BFRP) have many important industrial applications, their corrosion under extreme environments, such as those in gas and oil fields, still needs to be addressed. This paper investigates the influence of high‐temperature, high‐pressure, and H 2 S/CO 2 environments, simulating acidic oil and gas field conditions, on the mechanical properties and corrosion of basalt fiber (BF) and BFRP. Silicon nanowires (SiNWs) were grown in situ on the BF surface and combined with waterborne polyurethane (WPU) to achieve a synergistically modified BF. Compared to the unmodified BF/epoxy (EP), the flexural modulus, flexural strength, and interlaminar shear strength (ILSS) of BF‐SiNW‐WPU/EP increased by 13.2%, 23.7%, and 16.5%, respectively. After 72 h of H 2 S/CO 2 exposure, the flexural modulus, flexural strength, and ILSS of BF/EP decreased by 29.6%, 37.5%, and 17.4%, respectively, while those of BF‐SiNW‐WPU/EP decreased by only 20.7%, 24.6%, and 8.3%, respectively, thus demonstrating the improved corrosion behavior of the modified material. Furthermore, the corrosion caused by H 2 S/CO 2 mixed gases was more severe than that caused by a single gas, with H 2 S inducing more significant degradation than CO 2 . This work provides valuable insights into enhancing the durability of basalt fiber reinforced polymers for applications in oil and gas fields. Highlights BF was synergistically modified with SiNWs and WPU. The mechanical properties of BF‐SiNW‐WPU/EP were significantly improved. BF‐SiNW‐WPU/EP exhibited the improved corrosion behavior.