The influence of drying temperature on preservative penetration in Sentang wood (Azadirachta excelsa)

Sentang wood is a fast-growing species. Sentang wood has disadvantage which is poor durability towards termite and fungus attacks. Preservative is a method to improve the durability of wood against termite attacks and fungus decay. The objectives for this research was to investigate the effect of different drying temperatures on preservative treatability in Sentang wood. In addition, the suitable drying temperature for preservative treatment of Sentang was also examined. In this research CuAZ was used as preservative. Before the preservative treatment, the wood was dry under air-drying condition, temperature of 60, 80, 100 and 120°C. Results from wood drying showed that Sentang wood dried under temperature of 120°C has the faster drying time compare to the other drying conditions. While Sentang wood dried under air-drying condition has the longest drying time. For preservative retention test, the wood samples were place in vacuum chamber under 181.3 kPa pressure for 10 minutes and then wood samples were soaked in CuAZ solution under atmospheric pressure for 30 minutes. The weight of each sample was measured before and after treatment. While, for preservative penetration, the wood samples were cut at 1 cm length interval and percentage of preservative coverage area of the cross-section of each 1-cm-length sample was analysed by using image analysis software. The results obtained were as follow: drying at temperature of 120°C showed the highest preservative retention and penetration. However, the values were very low compare to the other fast-growing species. This is probably because Sentang wood has high amount of deposits substance and extractive that prevent the preservative penetrate into the wood. It is suggested longer soaking time or penetration under pressure are needed to improve the amount of preservative penetrate into the wood.