Rakha,M.M.***
*Dept. of Des. & Prod. Engineering, Faculty of
Engineering, Ain Shams University,
**Dept. of Forestry and Wood Technology, Faculty of
Agriculture, Alexandria University.
***Modern Arab Company for Wood Industries (MATIN), Alexandria, Egypt.
Abstract
Cotton is one of the main crops being cultivated in about 420,000 ha in Egypt. Therefore, cotton stalks (CS) are being burned at the present time after cotton collection to get rid of the cotton boll pink worm residing in the unopened bolls. This is very uneconomic and environment-unfriendly. It is suggested to use CS in particleboard (PB), especially because PB factories in Egypt suffer an acute shortage in raw material supply. Laboratory PB specimens were manufactured from air-dried CS. CS pieces were processed by a hammer mill: the whole outcome was classified via a sieving unit into coarse and fine particles. The particle mix was blended with the urea- formaldehyde resin in a blender, hand-formed into a mat and introduced in an automatic press using a wet cycle to cope with the large moisture content of the CS particles. Thus, CS boards (CSB) were manufactured under different pressing conditions (25 – 35 kg/cm2) and glue levels (9-14%). The static bending, internal bond, face strength and thickness swelling tests were conducted on CSB and density determined. The results of these tests indicate that the three-layer CSB fully satisfies the requirements of the Egyptian standard 906/1991 for PB, similar to BS 5669-1979. under most of the investigated conditions, the one-layer CSB satisfied the requirements of the aforementioned standard. To evaluate the potentiality of use of CS in particleboard on the pilot scale 326 tons (air-dry weight) of CS were converted into bales and transported to one of the distinguished particleboard factories. Different blends of casuarina: CS were used, and namely, 100:0, 85:15 and 0:100% on the three-layer 16 & 10 mm thickness particleboard production line of the factory. Specimens were taken from the products to assess their physical and mechanical properties. The analysis of the test results indicates that the use of CS in particleboard doesn't lead to significant sacrifice in their properties. This opens the way to use CS, being a cheap renewable agricultural residue, as a substitute for casurina being in short supply in Egypt and the whole Arab region.
33rd International Particleboard Composite Materials
Symposium & Pre-Symposium Technical Workshop
Hamed I. El-Mously*, M.M. Megahed**, M.M. Rakha***
*Dept. of Des. & Prod. Engineering, Faculty of Engineering, Ain Shams University,
**Dept. of Forestry and Wood Technology, Faculty of Agriculture, Alexandria University.
***Modern Arab Company for Wood Industries (MATIN), Alexandria, Egypt.
Abstract
Cotton is one of the main agricultural crops being cultivated in Egypt. The annual yield of cotton stalks (CS) from about 420,000 ha of cotton being cultivated annually is estimated to be 1.6 million tons (air-dry weight). Cotton stalks are an important lignocellulosic renewable resource in a country that suffers from an acute shortage of wood resources. Cotton stalks were traditionally used as a fuel in rural ovens. This traditional pattern of CS ultilization is associated with the renewal of the cycle of cotton boll worm, which resides in the unopened bolls in CS, causing an annual crop loss of about 20 percent. As a result of the cotton boll damage, CS are being burned after cotton collection. This practice is very environmentally-unfriendly and uneconomic. This study suggests the use of CS as a furnish in particleboard (PB), especially in light of the fact that PB factories in Egypt face an acute shortage of furnish supply. Field experiments have indicated the possibility of the use of tractor-operated threshers and bale presses in the milling and transformation of CS into bales of appropriate dimensions, weight, and bulk density (~ 0.25 ton/m3) for transport to PB factories. This method will guarantee lower investiment in equipment, lower energy and transportation costs, and labor opportunities in villages. Laboratory PB specimens were manufactured from air-dried CS (~ 10% moisture content (MC)). CS pieces were processed by a hammer mill and the resulting particles were classified via a sieving unit into coarse and fine particles. The particle mix was blended with a urea-formaldehyde resin in a blender, hand-formed into a mat, and introduced into an automatic press using a wet cycle to cope with the large MC of the CS particles. One-and three-layer specimens were thus prepared. In a series of experiments on the one-layer PB, CS were used with the leaves and bolls intact. CSPB specimens were manufactured under different pressing conditions (25 to 35 kg/cm2) and glue levels (9 to 14%). Static bending (SB), internal bond (IB), face strength (FS), and thickness swelling (TS) tests were conducted on CSPB specimens and the density of the specimens determined. The values of modulus of rupture (MOR) varied from 18.1 to 24.1, 11.7 to 18.5, and 11.3 to 15.7 N/mm2 for the three-layer, one-layer, and one-layer CSPB with leaves and bolls, respectively. The density varied from 0.7 to 0.8 gm/cm3 for all board types. The values of the modulus of elasticity (MOE) varied from 2,457 to 3,237, 1,698 to 2,727, and 1,779 to 2,406 N/mm2 for the three CSPB types. The values of IB varied from 0.64 to 1.1, 0.70 to 0.74, and 0.86 to 1.21 N/mm2. The values of FS for the three-layer CSPB varied from 1.38 to 1.72 N/mm2. the values of TS after 2 hours varied from 3.6 to 8.3, 7.1 to 26.1 and 8.4 to 14.0 percent for the three investigated CSPB types. These results indicate that the three-layer CSPB fully satisfies the requirements of the Egyptian standard 906/1991 for PB (similar to BS 5669 – 1979). Under most of the investigated conditions, the one-layer CSPB satisfied the requirements of the aforementioned standard. An increase in adhesive level had a positive significant effect on MOR, MOE, IB, and TS for all board types. The addition of leaves and bolls decreased the mechanical properties but improved the TS of the CSPB. The results from this study suggest that there is a real potential for the use of CS in the manufacture of three-layer PB without any sacrifice in product quality.
