WOOD RESEARCH Volume 62, Number 4, 2017
Dong Wang, Li Min Peng, Feng Fu, Bo Qi Song, and Mei Hong Liu

Changes of microscopic structures and sound absorption properties of decayed wood

Utilizing waste decayed wood is an effective method of conservation woodresourceand protection environment.In this paper, the sound absorption property of decayed poplar wood (Populus tomentosa) was investigated by analyzed the changes of microscopic structure, pore characteristics and sound absorption properties. Experimental results indicated that the sound absorption coefficientof decayed poplar woodwas significantly improved compared with the health wood. The components of cell wall were decomposed after decayed resulting in the pit membrane being disappeared, even the cell wall are decomposed and formed new pores. In addition, the pore size and connectivity increased, flow resistivity and sound impedance decreasing for the decayed poplar wood. Those results revealed that propagation path and internal friction between sound wave and cell wall increased, resulting in the acoustic attenuation increasing. The decayed waste woods as a sound absorption material would become possible.

WOOD RESEARCH Volume 62, Number 1, 2017
HUICHUAN JIANG and Feng Fu

Colorimetric and thermochromic properties of reversible thermochromic wood

To endow wood materials with a thermochromic function, an organic thermochromic agent consisting of thermochromic dye, bisphenol A (BPA) and long-chain alcohols (1-tetradecanol (TD), or 1-hexadecanol (HD)) was used as a dye to prepare reversible thermochromic wood (RTCW). The colorimetric properties, including total color difference (ΔE*ab), lightness index (L*), red-green index (a*), and yellow-blue index (b*), were investigated at different temperatures. The color change temperature range and color hysteresis of RTCW were also analyzed. The color difference unit of National Bureau of Standards (NBS) was used to determine the color change temperature range and the achromic (chromic) temperature. In the decolorization process, with the temperature increasing, the values of ΔE*ab, L* and b* of the RTCW samples increased, and the values of a* decreased, but the values of ΔE*ab, L*, a*, and b* were just opposite in the colorization process. Meanwhile, the color of the RTCW with TD or HD could repeatedly change between red and light brown (wood colore) within a color temperature range of 25-35°C or 37-49°C respectively, presenting a “color hysteresis” phenomenon over a heating (decolorization) and cooling (colorization) cycle. The achromic and chromic temperature of the RTCW samples with TD was 31°C and 25°C respectively while RTCW samples with HD was 43°C and 37°C.