IMPROVING THE PROPERTIES OF RICE STRAW HARDBOARD BY BLENDING WITH OTHER RAW-MATERIALS

The effect of blending Egyptian rice straw pulp with different pulps, namely bagasse, reeds, cotton stalks, barley straw and wood wastes on the physical and mechanical properties of the finished hardboards was investigated. Two concentrations of phenol formaldehyde resin (1.5% and 3%) were used. In presence of 3 per cent resin content the properties of all unblended and blended boards were superior than boards containing 1.5 per cent resin. A clear relationship was found between the pentosan content of the different pulps and the bending strength of the finished boards. Lack of pentosans renders the board more brittle, while its abundance imparts flexibility to the board and improves its bending strength. Blending rice straw pulp with bagasse pulp caused the optimum improvement in the bending strength of the finished board. A noticeable improvement in the thickness swelling was observed on blending rice straw pulp with pulps from reeds and wood wastes.