THE EFFECTS OF HEAT TREATMENT ON THE PHYSICAL AND MECHANICAL PROPERTIES OF WHITE AFARA WOOD (TERMINALIA SUPERBA)

ABSTRACT

The heat treatment of wood is an environmental friendly method for wood preservation. This process improves wood resistance to decay and its dimensional stability. In this study, the physical properties of White Afara wood( Terminalia superb) such as density, moisture content and shrinkage were investigated as well as mechanical property such as compression strength. Woods specimen that had been conditioned at 65%  relative humility and 20 ± 2ºC temperature were subjected to heat treatment at ( 80, 100, 120, 140 and 160)ºC. Thereafter, at an optimum temperature 1200C, the duration of heat treatment was varied for 2,4,6 and 8 hours for each specimen. In the course of this experiment, at 1400C and 1600C split along the grain of the wood specimen were observed, the colour of the wood becomes more darker and the wood becomes more brittle as temperature increases. Hence, the choice of 1200C optimum temperature at 6 hours duration. The flash point of the experiment was determined at 1800C. Due to its good weather resistance, White Afara wood when heat treated at1200C optimum temperature is best suitable for outdoor applications such as external cladding, window frames and garden furniture.

CHAPTER ONE

1.0    INTRODUCTION

This chapter begins with an overview of wood in Nigeria, the need to study the heat treatment of Nigerian woods, the significance of the study, the aim and objectives of this research and the limitations .

1.1 Overview of wood in Nigeria

Wood in the Nigerian society can be broadly classified as hardwood and softwood. Hardwood is derived from angiosperm or broad-leaved trees such as Afara (Terminalia superba) and Danta (Nesogordonia papaverifera).Softwood is obtained from coniferous trees, which have needle-like leaves such as Araba (Ceiba pentadra) and Obeche (Triplochiton scleroxylon).Wood, from time immemorial has established itself as a substantial material for variety of applications, such as constructions of building, furniture items, bridges, boats, ships, lorry and tractor wagons and aircraft carrier (Fuwape 2000). Indeed, one of the first major innovations of mankind was utilizing fire, fueled by wood, for cooking and heating. Since this ancient beginning, the uses of wood, and the value of the forest, have expanded dramatically, as the population of humans and their economies grew. Other important products that forests provided were food, in the form of berries, nuts, fruits, and wild animals (Christopher 2005).Furthermore, wood was the most important material in early human economies, and though other materials have grown in importance, wood used for solid products, fibre, and chemicals is still the largest single type of raw material input by weight (Haynes 2003).Today, wood is still being used in tools, paper, buildings, bridges, guardrails, railroad ties, posts, poles, mulches, furniture, packaging, and thousands of other products. According to Keay (1964), Nigerian forests are naturally blessed with over nine hundred different species of trees which are main sources of timber products. The abundant availability of these trees in Nigeria is attributed to prolonged rainy season, resulting in high annual rainfall (above 2000milimetres), which ensures adequate supply of water and promotes perennial tree growth.

1.2 The need to study the heat treatment of Nigerian woods

A survey of the available literature and journals as well as research activities carried out at various forest research institutes in Nigeria such as Forest Research Institute of Nigeria (FRIN) Ibadan and Engineering Materials Institute (EMDI) Akure revealed no information on the effect of heat treatment on wood in Nigeria

1.3      The Significance of the Study

To provide forest managers, woodworkers, and wood designers adequate information required on the heat treatment of White Afara wood (Terminalia superba) for various applications that require specific qualities. Also, to provide improved information to the wood using industries about characteristics of heat treated woods for future timber supplies, thus, to make strategic processing and investment decisions

1.4       Aim and Objectives of the research work

The aim of this research is to determine the optimum processing temperature of white Afara wood (Terminalia superba). Moreso, to recommed White Afara wood (Terminalia superba) for suitable technological applications for industrial uses.

1.5       Limitations to the study

Only some few physical and mechanical properties of White Afarfa wood (Terminalia superba)  were tested due to limited testing equipment. In addition due to huge cost of purchasing, sawing, machining and experimenting on the woods, Samples for this test were only taken from the middle log

1.6 Thesis outlines

Chapter One contains an introduction to the thesis, overview of wood in Nigeria, the need to study the heat treatment of Nigerian woods, the significance of this study, aim and objectives of this research and the limitations. Chapter Two evaluated the physical properties such as density, moisture content and shrinkage as well as mechanical property, compression strength, grain directions and strength of wood, wood microstructure, wood processing, wood conservation and utilization, wood seasoning, classification of timber for drying, and methods of drying timber. Chapter Three discuss the material and methods used to obtained the desired results. Chapter Four presents the result and discussion while Chapter Five covers the conclusion and recommendations.

Related Project Topics :