Selected Physical and Mechanical Properties of Microwave Heat Treated Rubberwood (Hevea brasiliensis)

Aujchariya Chotikhun,Jitralada Kittijaruwattana,Salim Hiziroglu,Emilia-Adela Salca

doi:10.3390/app10186273

Aujchariya Chotikhun, Jitralada Kittijaruwattana + Show 2 more

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https://doi.org/10.3390/app10186273

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Abstract

The objectives of this study were to evaluate some of physical and mechanical properties of rubberwood (Hevea brasiliensis) as function of microwave heat treatment process. The specimens were heat treated at three temperature levels of 150 °C, 180 °C, and 220 °C for 20 min in a small microwave oven connected to a computer. Bending characteristics, namely modulus of elasticity (MOE), modulus of rupture (MOR) as well as hardness of the samples were tested. Dimensional stability in the form of swelling and water absorption of the specimens were also determined. Based on the findings in this work it appears that microwave can be used successfully for heat treatment of rubberwood. Overall mechanical properties of the samples were adversely influenced by the treatment. MOE, MOR and hardness values of the samples treated at a temperature of 220 °C had 2.37, 3.69, and 2.12 times reduced than those of control samples, respectively. Dimensional stability of the heat treated samples as a result of 2-h and 24-h water soaking improved. Micrographs take from scanning electron microscope (SEM) and transmission electron microscope (TEM) revealed that certain amount of damage took place in the cellwall of the treated specimens. Overall discoloration on the samples due to microwave heat treatment was found insignificant.

Highlights

IntroductionHeat treatment or thermal modification of wood is one of the most widely used methods to improve overall properties of the unit so that it can be used more efficiently during its service life
Heat treatment or thermal modification of wood is one of the most widely used methods to improve overall properties of the unit so that it can be used more efficiently during its service life.Heat treatment of wood at commercial scale was developed in Europe in 1990 and became an accepted technique for various applications [1,2,3]
The samples of rubberwood were treated in the microwave system at the temperature levels of 150 ◦ C, 180 ◦ C, and 220 ◦ C for 20 min. by using a software

Summary

Introduction

Heat treatment or thermal modification of wood is one of the most widely used methods to improve overall properties of the unit so that it can be used more efficiently during its service life. Heat treatment of wood at commercial scale was developed in Europe in 1990 and became an accepted technique for various applications [1,2,3]. The fundamental of heat treatment of wood and wood products is modification of chemical decomposition of the member using a scheduled pyrolysis to enhance its properties. Some of the major advantages of heat treatment include improvement of dimensional stability, resistance to biological deterioration and imitate more expensive wood species by changing overall color of the processed unit. Heat treatment is one of the most practical techniques to improve hygroscopicity of wood and wood products with an acceptable cost

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