Chemical conversion
Saeed Hasani; Mohammad Talaei poor; behzad baziyar; Amir Homan Hemmasi; Saeed Mahdavi
Abstract
AbstractIn this study, black poplar (Populus nigra) cut from Zanjan province was used in two age groups of 18 and 38- year-old. Timbers with thicknesses of 4, 5 and 6 cm were prepared from each age group. The prepared timbers were modified during the heat treatment process (Thermowood) at a constant ...
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AbstractIn this study, black poplar (Populus nigra) cut from Zanjan province was used in two age groups of 18 and 38- year-old. Timbers with thicknesses of 4, 5 and 6 cm were prepared from each age group. The prepared timbers were modified during the heat treatment process (Thermowood) at a constant temperature of 212 °C. Experimental samples were obtained from the surface and middle depth of heat-treated timbers. Heat-treated and control wood samples were subjected to accelerated weathering for 150 hours. Color lightness (L*), color difference (ΔΕ*) and water droplet contact angle were measured for heat-treated and control samples before and after weathering. In order to investigation of the wettability content, the method of measuring the contact angle of the water drop - static according to the ASTM D 5946 standard was used. In general, before weathering, the brightness of the heat-treated samples decreased compared to the control sample, but after weathering, the color lightness of the control samples decreased and the color lightness of the heat-treated samples increased. Also, the content of color difference of samples after weathering compared to before weathering showed a significant decrease statistically. Heat treatment increased the contact angle of water droplets of the samples 60.31% and the contact angle of water droplets of the heat-treated and control samples increased significantly after weathering compared to before weathering.
Afsaneh Topa; Atamalek Ghorbanzadeh; Davood Efhamisisi
Abstract
The plasma has different effects on the surface wettability of wood, depending on the treatment conditions and the type of gas used. The hdrocarbon gases usually destroy hydrophilic groups on the surface of wood and cause hydrophobicity by creating microscopic rough structures. In this study, glide plasma ...
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The plasma has different effects on the surface wettability of wood, depending on the treatment conditions and the type of gas used. The hdrocarbon gases usually destroy hydrophilic groups on the surface of wood and cause hydrophobicity by creating microscopic rough structures. In this study, glide plasma treatment with methane was used to hydrophilize the surface of the wood and create weathering resistanc. The poplar wood (Populus deltoides) were exposed to glide plasma under various laboratory conditions such as time of exposure, voltage, frequency, distance between electrodes as well as flow of inlet gas and outlet gas with methane inside a reactor. Then the surface properties of wood were studied using scanning electron microscope (SEM), measurement of water drop contact angle, ATR‐FTIR spectroscopy, roughness survey, and colorimetry. The specimens were then subjected to the accelerated weathering using the Gardner weathering wheel and their properties were checked again. The SEM images showed that the plasma creates a warty layer on the surface of the wood which could be due to the deposition of new materials or the physical effects of plasma (surface etching). The plasma treatment significantly increased the contact angle of the water droplet on the surface of the treated samples. The treated samples had a higher surface roughness than the control samples. The surface of treated samples was generally darker than the control. After exposure to the accelerated weathering, the effect of treatments on surface hydrophobicity was largely lost. The treated samples had less roughness changes than the control after exposure to the weathering, and also their dark color changed to silver-gray. The use of glide plasma with methane gas showed the great potential for creating hydrophobic surfaces on the wood, but it did not last long and lost its effectiveness due to weathering.
Management and Economics wood
Mehdi Jonobi; Shabo Salehpoor; zhreh Araaznia; Yahya Hamzeh
Abstract
This study was carried out to investigate the effect of storage time on the color and chemical compounds of bagasse particleboard made. For this purpose, the three levels of stored and fresh bagasse from karoon particleboard Company were used. In addition, the chemical compositions ...
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This study was carried out to investigate the effect of storage time on the color and chemical compounds of bagasse particleboard made. For this purpose, the three levels of stored and fresh bagasse from karoon particleboard Company were used. In addition, the chemical compositions were determined according to the TAPPI test methods and also biometrical (slenderness ratio) was done using the fiber dimension measured by Franklin method. The results showed that the amount of lignin was different in the stored samples at three levels, but the difference in the amount of cellulose and extractive was not observed. The results illustrated that the color changes in the stored bagasse were more than fresh sample. Identification of the microorganisms in stored samples was done and results showed that most of microorganisms were bacteria and yeast. The results showed that the storage time can significantly effect the color and physical properties of stored bagasse.
