Tensile properties and water absorption of Gigantochloa Scortechinii bamboo strip with epoxy layer coating under sea water conditions

Bamboo is a promising material for marine structures, but its durability is challenged by the high salinity of seawater. This study investigates the tensile properties and water absorption behavior of Gigantochloa Scortechinii bamboo strips coated with one or two layers of epoxy, exposed to varying seawater salinity levels (100 %, 50 %, and 0 %). Prior to coating, the bamboo strips underwent heat treatment at 160 °C, 170 °C, and 180 °C. The results show that bamboo treated at 170 °C and coated with two layers of epoxy significantly improved tensile strength, with a 108.16 % increase before seawater immersion and a 96.92–98.46 % improvement after immersion in 0 % salinity seawater. Tensile strength decreased more in higher salinity levels (50 % and 100 %), despite lower water absorption in these conditions. The study also found reduced water absorption and thickness swelling in bamboo strips treated at 170 °C with a double epoxy coating. Fourier Transform Infrared Spectroscopy (FTIR) confirmed chemical changes due to heat treatment and successful epoxy deposition, while Field Emission Scanning Electron Microscopy (FESEM) revealed that the double epoxy coating created a smoother surface, effectively sealing pits and micro-cracks. However, prolonged seawater exposure caused the epoxy to peel. Overall, the findings demonstrate the potential of treated and epoxy-coated bamboo as a sustainable and eco-friendly alternative to conventional materials for marine applications. • The novelty of this study lies in its unique combination of heat treatment at varying temperatures (160 °C, 170 °C, and 180 °C) with single and double-layer epoxy coatings to enhance the properties of Gigantochloa Scortechinii bamboo strips, specifically under different seawater salinity conditions (0 %, 50 %, 100 %). • Heat Treatment : Bamboo strips were heat-treated at 160 °C, 170 °C, and 180 °C to enhance fiber-matrix adhesion before epoxy coating. • Analytical Methods : FTIR analysis confirmed successful epoxy coating and heat treatment effects, while FESEM was used to examine coating distribution and thickness. • Superior Performance : Double-layer epoxy-coated specimens exhibited significantly lower water absorption and thickness swelling, especially those heat-treated at 170 °C. • Enhanced Tensile Strength : Specimens treated at 170 °C with double-layer epoxy coating showed the highest tensile strength both before and after immersion. • Overall Improvement : The combination of heat treatment and double epoxy coating effectively enhanced the water resistance and tensile strength of bamboo strips in seawater conditions.