THERMOPHYSICAL PROPERTIES OF DIFFERENT SIZES OF WOOD PARTICULATE MATERIALS FOR OPTOELECTRONICS DEVICE APPLICATIONS

Abstract

The thermophysical properties of five different wood species of the family of Sterculiaceae, Moraceae and Ulmaceae and their applications in optoelectronics devices have been investigated. The species are; Celtis phillipensis, Milicia excelsa, Pterygota macrocarpa, Antiaris africana and Guarea cedrata. The wood materials were pulverized into particles and oven-dried at 50°C for 40 minutes to avoid redistribution of water under the influence of temperature. A mechanical test sieve shaker was used to sieve the particle using five different mesh sizes: 106 μm, 300 μm, 425 μm 850 μm and 1180 μm respectively. The basic apparatus used was a Differential Thermal Analyzer (DTA). It was revealed that as particle sizes reduced, thermal conductivities, diffusivities and effusivities of the particles increased. This was due to reduction in the intermolecular distances between the grains. The thermal conductivity, diffusivity, effusivity and hardness values obtained ranged between 0.0100Wm -1 K -1 -0.0492 Wm -1 K -1 ; 1.00×10 -6 m 2 s -1 -8.90×10 -6 m 2 s -1 ; 3.309 Ws 1/2 /m 2 K -11.426 Ws 1/2 /m 2 K and 6.65BHN– 1.27BHN respectively for all the samples. The research revealed the influence of particle sizes on thermal conductivities, diffusivity, effusivity and hardness of wood materials. Almost all the values obtained in this research fall within the range of that of polystyrene whose efficiency in optoelectronics devices has been established. Hence, the material would be useful in optoelectronics devices. Also, some of the wood materials showed similar thermal insulation properties most especially thermal conductivity to that of some commonly used materials for flat plate solar collector which ranges between 0.1202-0.0245 Wm 1 K -1 . The results obtained also indicated that some of the materials especially Milicia excelsa, could be used in flooring due to its high ability to resist deformation.