Effect of Low Temperature Reactive Dye Reactive Red 2 on Dyeing and Tensile Properties of Twisted Bamboo Fibers

[Image: see text] This study employed bamboo as the raw material and employed the sodium chlorite method to remove most of the chromogenic groups in bamboo. The low-temperature reactive dyes were then utilized as the dyeing agents in combination with the one-bath method to dye the decolorized bamboo bundles. The dyed bamboo bundles were subsequently twisted into bamboo fiber bundles with high flexibility. The effects of various factors, including dye concentration, dyeing promoter concentration, and fixing agent concentration, on the dyeing properties, mechanical properties, and other properties of the twisted bamboo bundles were investigated using a tensile test, dyeing rate test, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The results indicate that the macroscopic bamboo fibers prepared by the top-down method have excellent dyeability. The dyeing treatment not only improves the aesthetics of bamboo fibers but also improves their mechanical properties to a certain extent. When the concentration of dye is 1.0% (o.w.f.), the concentration of dye promoter is 30 g/L, and the concentration of color fixing agent is 10 g/L, the comprehensive mechanical properties of the dyed bamboo fiber bundles are the best. At this time, the tensile strength is 95.1 MPa, 2.45 times that of undyed bamboo fiber bundles. XPS analysis results show that the relative content of C–O–C in the fiber is significantly increased compared with that before dyeing, which indicates that the formed dye fiber covalent bond can strengthen the cross-linking between fibers, thus improving its tensile performance. The covalent bond is stable, and the dyed fiber bundle can retain its mechanical strength even after high temperature soaping.