Advancing green retrofitting: Investigating bamboo and coconut fiber composites under chemical and thermal stresses

Natural fiber-reinforced polymers (NFRPs) are promising sustainable materials for structural retrofitting, yet their durability under chemical and thermal stresses remains underexplored. This study compares bamboo and coconut fiber-reinforced polymer composites exposed to 5% hydrochloric acid, 5% sodium hydroxide, 5% sodium chloride, and temperatures up to 200°C. Laminates were fabricated and tested for tensile and flexural properties, with microstructural analysis via scanning electron microscopy. Bamboo composites showed significant degradation, especially under acidic and saline conditions, with flexural strength reductions up to 67%. In contrast, coconut fiber composites demonstrated greater chemical and thermal resilience, maintaining or improving tensile strength and exhibiting better stability at elevated temperatures due to higher lignin content. These results suggest coconut fiber composites are more suitable for retrofitting applications in aggressive environments. The findings contribute to advancing sustainable construction by identifying natural fiber composites with enhanced durability for environmentally responsible structural rehabilitation.