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Dimensional Stabilization of African Whitewood by Treatment with Modified Chitosan
Abstract
Effect of modified chitosan on physical and mechanical properties of Triplochiton scleroxylon (African whitewood) wood was investigated. The chitosan was chemically modified by introducing more amino groups to the backbone of chitin using parabenzoquinone (pBQ). Obeche wood blocks were impregnated with modified chitosan and commercial chitosan at six different concentration levels (0.2%, 0.4%, 0.8% of modified chitosan (MC) and 0.2%, 0.4% 0.8% of unmodified Chitosan (C). The derivatives were characterized by Fourier Transformed infrared (FT-IR) spectroscopy. Physical properties – water absorption (WA) and water repellent efficiency (WRE) and mechanical properties – modulus of rupture (MOR) and modulus of elasticity (MOE) were determined. The IR spectra at different major peaks confirmed the modification of chitosan. Water Absorption for all the treated samples after 24 -hour and 168- hour water-soak tests ranged between 43.41-50.37% and 86.82-99.68% which were lower than the untreated with 57.92% and 119.5% respectively. The WRE of modified chitosan-treated wood improved considerably with the treatment of samples. There was no significant reduction in the mechanical properties of the treated samples over the untreated ones. Therefore, treating wood with chitosan or modified chitosan is advised for outdoor uses where the wood would be exposed to moisture.