Secado industrial

J. Agric. Sci. Technol. (2008) Vol. 10: 461-470

Properties of Medium Density Fiberboard Made from Wet and Dry Stored Bagasse
H. Zare-Hosseinabadi1∗, M. Faezipour1, A. Jahan-Latibari2, and A. Enayati1

ABSTRACT
Medium Density Fiberboard (MDF) was produced using moist depithed bagasse stored dry or wet. The duration of storage for either method varied between 0 to 4 months. Two steamingtemperatures of 175°C and 185°C were also used. MDF boards were produced ° ° in the laboratory and the common mechanical and physical properties were measured and compared. Results showed that an increased steaming temperature and storage time (especially for the wet storage method) have negative effects on the mechanical properties and positive effects on the physical properties (water absorption andThickness swell). The mechanical properties of boards produced from bagasse as received (fresh bagasse) and at a steaming temperature of 175°C were superior to others. The modulus of Rupture ° (MOR), Modulus of Elasticity (MOE) and Internal Bond (IB) of boards from fresh bagasse were 29.7 MPa., 3,127 MPa., and 0.52 MPa. respectively. However, the physical properties of boards produced frombagasse after 3 months’ wet storage and a steaming temperature of 185oC were superior, and were measured at 44.3% and 63.9% for water absorption after two and 24 hours’ immersion (WA2, WA24 ), and 11.5% and 17.6% for Thickness Swelling after two and 24 hours immersion (TS2, TS24 ) respectively. Keywords: Bagasse, Dry storage, MDF, Mechanical properties, Physical properties, Steaming temperature, Wetstorage.

INTRODUCTION The wood and paper industries in the Middle East are faced with a limitation of wood fiber supply. In order to overcome this problem and fulfill the needs of society’s demands, attention is focused on utilizing non-conventional raw materials such as agricultural residues. Even though the utilization of such residues has not been common in countries with abundant forests andwood supply, there have been attempts to use these residues in North America. However, for countries like Iran, agricultural residues show excellent potential and, among them, sugarcane residues which are by-product of sugar extracting
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operation are unique. Bagasse is abundant, unused, and can be obtained at low cost. Its lignin content is low and its open structure will facilitate liquidpenetration. However, it possesses two drawbacks: its open structure will adversely affect the strength and integrity of the fibers, and it is a seasonal by-product that is available only during a short period of time (Habibi et al., 2002). Sugarcane is a seasonal growing plant and its harvesting period varies between 4 to 8 months, usually five months in Iran. Therefore, in order to satisfy the rawmaterial requirements of a board plant, it must be collected and stored for the rest of the production period. Raw bagasse, which is

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Department of Wood and Paper Engineering, Faculty of Natural Resources, University of Tehran, Karaj, Tehran, Islamic Republic of Iran. ∗ Corresponding author, e-mail:Zare.hamid@gmail.com 2 Faculty of Agriculture, Azad University, Karaj, Tehran, Islamic Republic of Iran.

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acquired from sugar extracting mills, contains almost 50% moisture content (wet basis), pith and some residual sugar. This bagasse at 50% moisture will provide an excellent growth environment for microorganisms(Kollmann et al., 1975) and growth of these microorganisms will deteriorate the quality of fibers and therefore the quality of final products. For this reason, suitable storage methods must be foreseen to minimize such deterioration. Any storage method employed must eliminate the growth conditions for deteriorating agents. This is usually accomplished either by the elimination of oxygen or by...