Effect of the bleaching treatment on the colour difference and lignin ratio of Manglietia conifera and Styrax tonkinensis wood used as base materials of transparent wood composites
Keywords:
Bleaching, lignin,, Manglietia conifera Dandy,, Styrax tonkinensis (Pierre) CraibAbstract
This study investigated the change of colour and lignin ratio of Manglietia conifera and Styrax tonkinensis wood after the bleaching treatment using hydrogen peroxide (H 2O2) and sodium hydroxide (NaOH) agents, used as base materials of transparent wood composites. Results showed that there was a significant difference in the colour change (ΔE) of both Manglietia conifera (20.68) and Styrax tonkinensis (28.18) after the bleaching treatment. The colour of the two timbers after bleaching was much lighter (ΔL of Manglietia conifera: +5.53 and Styrax tonkinensis: +5.39). Furthermore, the colour of both timbers after the treatment also tend to be greener (-Δa) and yellower (+Δb). The lignin ratio of Manglietia conifera decreased by 60% while Styrax tonkinensis decreased by 80% after bleaching. Based on the results, it is indicated that Styrax tonkinensis wood is more suitable as a base material of transparent wood composites
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