Microstructural characterization and evaluation of certain important physical properties of thuja burl wood

Abstract

This investigation aimed to characterize certain important anatomical, chemical and physical properties of Tetraclinis articulate (Thuja) burl wood from Morocco. Anatomical properties and constituent structure were analysed using image analysis system, environmental scanning electron microscope (ESEM) and powder x-ray diffraction techniques. A few important physical properties of Thuja burl wood such as density, specific gravity, equilibrium moisture content (EMC), total swelling and water absorption characteristics were evaluated. Real-time water absorption and swelling profiles were recorded electronically using a digital force sensor and linear variable differential transformers (LVDTs) respectively. Microscopic structure observed on fractured surfaces showed very compact and thread-like fibers. Average crystallinity index and diameter of cellulose crystallite was found to be 0.35±0.03 and 36.00±5.58 Å respectively. The average values of air-dry density and the EMC of Thuja burl wood were 932.67±50.57 kg/m3 and 10.19±1.43% respectively. Swelling profile as a function of the water immersion duration followed a curvilinear variation with maximum swelling coefficient of 2.9±0.43% after 24 hour from oven-dry condition. The suitability of this wood for decorative and handicraft items is attributed mainly to its dense microstructure, higher dimensional stability, lower water absorption, random grain texture, dark brownish with intense and pleasant smell.