Effect of Production Parameters on Electrical Properties of Woodceramics Made from Oil Palm Frond
Pongsak Hengniran, Boonyarit Panyayeun, and Trairat Neimsuwan
Woodceramics, a new kind of porous carbon material, has potential in many industrial applications, as it is nvironmental friendly and has a low production cost. In this research, woodceramics was prepared by carbonizing Medium Density Fiberboard (MDF), made from oil palm frond fiber impregnated with liquefied wood, converted from oil palm shell. Their ability to withstand maximum temperatures (600, 800, and 1,000 °C) and heating rates (1, 5, and 10 °C/min) during carbonization and changes in the physical and properties, as well as the electrical resistivity, were carefully investigated. The results indicate that during manufacturing, woodceramics lost a considerable amount of weight by about 60-65% and shrank in volume by around 45-62%. Physical properties, such as density, ranged between 0.6-0.85 g/cm3 with moisture content roughly between 2.9-13%, while their ability to absorb water varied between 23-65%, depending on carbonizing conditions. Examined by ASTM D257 method, the electrical properties of the obtained woodceramics were affected by the levels of maximum temperature and heating rate. The results showed a decreasing trend in the electrical resistivity with increasing maximum temperature. Electrical resistivity rapidly decreased beyond a maximum temperature higher than 600°C and did not change at maximum temperatures close to 900°C. Moreover, a higher heating rate increased the electrical resistivity of woodceramics. The electrical resistivity of the woodceramics ranged between 5.16×102-6.4×109 Ω-cm, therefore nearly all woodceramics produced could be categorized as a semiconductor, especially for maximum temperatures ranging between 800-1,000°C.