MONITORING OF RUBBERWOOD TREATMENT BY MICROWAVE DIELECTRIC PROPERTIES

Abstract

Nowadays wood is widely used in most country. Therefore, preservation of wood is very important to make sure that the wood can be used for a long time and do not decay due to some factors such as pest, insect, weather or other factors. Several methods are used to determine the effectiveness of wood preservation. Usually, the methods used in laboratory test are malt-agar culture tests, soil block test, and agar-block test. The other methods are permanence and accelerated exposure such as leaching test, weathering test, and stakes test. All these test are time consuming and expensive, because more chemical analyses involved, and none has been accepted as a standard for general use. In this study, we are monitoring the wood treatment by using microwave dielectric loss technique at frequency ranging from 0.2 to 3 GHz. The water borne preservatives used in this treatment were Borax, Alkaline Copper Quaternary (ACQ), and Chromate Copper Arsenic (CCA). Naturally, the dielectric properties of rubberwood are very small and the ionic conductivity can be negligible. After treated with chemicals preservatives which are having high ionic conductivity, the dielectric properties of treated wood are increased and become ionic. The dielectric loss and mass of the sample reduce in same pattern with time as water evaporated from the wood.