Properties Evaluation of Dyed Laminated Bamboo by Natural Dyes

This study aimed to determine the potential use of natural dyes on bamboo strips and analyze the effect of staining on the mechanical properties of laminated bamboo. The dye is extracted from the seeds of kesumba keling (Bixa orellana), avocado peel (Persea americana), and indigofera leaves (Indigofera tinctoria). Bamboo laminate is made from petung bamboo (Dendrocalamus asper) with a size of 5 x 30 x 370 mm. The natural dye that has been extracted is applied to the bamboo lamina through the immersion method. Laminated bamboo is produced by joining 4 laminates which are stained using Polyvinyl acetate (PVAc) adhesive. Color measurements were performed on each sample and calculated using the CIELab method. The mechanical properties of laminated bamboo tested were adhesive strength, compression parallel to fiber, and static flexural strength. The results showed a change in the color value of the three dyes used. The retention and penetration values varied in the three dyes. Laminated bamboo stained with indigofera extract obtained the highest bond strength value of 66.25 kg/cm² and inversely proportional to the compressive strength value parallel to the fiber. Staining by immersion appears to reduce the static bending value. However, the MOR values obtained meet the JAS requirements for all types of natural dyes.