Mechanical and morphological variations of basalt fiber in seawater and a strategy to improve its performance with nanocomposite sizing

Basalt fiber-reinforced polymers are expected as a promising candidate in the construction industry, especially in marine engineering. However, the study on the durability of basalt fiber (BF) exposed to seawater is still in its infancy. In this paper, the corrosion behavior of BF in seawater was discussed. The results manifested that the strength of BF generally increased and then reduced with accumulation of treatment temperature or duration in seawater. Notably, the tensile strength of BF increased by 22.5% in initial stage due to the Na+/K+ exchange between the fiber and seawater. As the interaction proceeded, multi-scale particles emerged on the fiber surface, followed by the formation of corrosion layer with different thickness. To address the problem caused by the seawater, nanocomposite sizing containing nanosheet was applied on BF surface, which could considerably enhance the mechanical and seawater-resistance performance of filament. In-depth analysis confirmed that such improvement originated from the synergetic effects of stress transfer and the barrier performance of nanosheet in nanocomposite sizing.