Discoloration and Degradation of Bamboo under Ultraviolet Radiation

Light is one of the most adverse factors for bamboo deterioration and causes surface degradation discoloration. The study was carried out to initiate efficient effective photodiscoloration modify enrich colors that may be applied dyeing. Different types samples commonly used in industry were studied experimentally under two ultraviolet (UV) light. Effects light sources, radiation time, distances on discoloration mechanism systematically studied. For both UV 313 high-pressure mercury light, turned red-yellow, color parameters including Δ E , id="M2"> a id="M3"> b id="M4"> C rapidly increased first then stabilized long while id="M5"> L showed a similar trend, except final decrease. Compared with 313, lamp highly took less time induce Heat treatments darkened slowed down photodiscoloration, higher temperature led more photostability. change scrimber slower than untreated due high density heat treatment, dark carbonized changed scrimber. Relatively contents isovanillin, syringaldehyde, β-hydroxypropiovanillone, p-hydroxybenzaldehyde, syringic acid identified by GC-MS, 2,6-dimethylbenzoquinone, 3-hydroxy-4-methoxybenzoic HPLC-MS from layer after radiation. These products all contained conjugated double bond conjectured degraded lignin or aromatic extracts. Particularly, 2,6-dimethylbenzoquinone which cyclohexenedione structure without benzene rings, chemically stable other bonds supposed product (chromogenic group) during photodegradation. Untreated light-colored high-energy initiated recommended being industrial traditional chemical dyeing, photoinduced dyeing method has no addition easy operate environmental-friendly.