The effect of heat treatment to the colour of Pauh Kijang (Irvingia Malayana)

Abstract

As timber with natural durability and excellence properties is limited and high in price, there is a need to make use of the timber with low durability and properties. In order to use this kind of timber, the timber needs to be treated to improvise its properties and durability. The well-known treatment used worldwide is by using chemical preservative; however, this kind of treatment is bad to the environment. Therefore, there is a need to find an alternative way to replace this treatment with an environmentally friendly way of treatment. Heat treatment is one of the treatments which may equip the timber with new properties without using any chemical or preservative but heat where the heat is used to achieve new material properties rather than to dry the wood. Heat treatment generally causes an apparent decrease in wood mechanical properties due to the material losses in the cell wall, hemicelluloses degradation and the modification of long chain molecules. Therefore, this study investigated the effect of heat treatment on the colour of one of the Malaysian hardwood timbers; Pauh Kijang which located in Strength Group 3 of timber (SG3) after had been treated by heat. The size of the timber beam for each sample is 50mm x 90mm x 1800mm. The total numbers of the sample are 90 which 15 numbers of sample allocated for control, kiln dried and four levels of heat treatment. There are four different levels of temperatures namely 150°C, 170°C, 190°C and 210°C were applied on the timber beam samples within 1 hour. Control and kiln dried samples been used as comparisons to each test conducted to identify the changes that occur on the colour after heated. The colour turned darker as the temperatures increased for these four species of heat-treated timber which had been analysed by CIE-Lab system.