Dyed bamboo composite materials with excellent anti-microbial corrosion

Bamboo, as a potential ecological building material, has attracted a lot of attention, due to its wide distribution, more than 1000 species, short growth cycle of 3–5 years, three times the carbon dioxide adsorption of other plants, and tensile strength comparable to steel or concrete. The major challenges of bamboo are the single color and poor anti-microbial corrosion, based on the intrinsic nature of polysaccharides such as cellulose. In this work, a novel bamboo composite material that exhibits a rich variety of colors (red wine, light yellow, coffee, white, black), excellent color retention, and anti-microbial corrosion for 14 days under a relative humidity of 60–95% is prepared by an easy-to-scale chemical grafting method. Oxidation treatment is the basic condition for bamboo to obtain bright colors, and the substitution reaction of the carbon heterocyclic ring of polysaccharide molecules is the inherent reason for bamboo dyeing. For instance, the bamboo treated with nitric acid presents a bright red wine color, and C=N, –NO2 functional groups are detected. Polyethylene glycol filled in the three-dimensional network avoids the water-soluble nutrients from emigrating to the surface of bamboo. The interruption of the continuous supply route allows the modified bamboo to obtain excellent antibacterial performance. Bright color and anti-microbial corrosion characteristics make the modified bamboo as a green building material has more potential applications.