FACULTY OF AGRICULTURE
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Item Physical and mechanical properties of cement-bonded particleboards produced at different water pre-treatment temperatures and cement/wood mixing ratios(Forest and Forest Products Society, 2011) Badejo, S.O.; Omole, A. O.; Fuwape, J. A.; Oyeleye, B. O.The influences of water pre-treatment temperature and cement/wood mixing ratios on static and moisture response properties of cement-bonded particleboards produced from mixed Nigerian hardwood species were assessed in this study. The process variables for board fabrication were pre-treatment temperature (5 levels) and wood/ cement mixing ratios (5 levels) resulting in 25 treatment combinations in a factorial experiment. The examined properties are modulus of rupture (MOR), modulus of elasticity (MOE), water absorption (WA), thickness swelling (TS) and linear expansion (LE) properties of the experimental cement-bonded particleboards. Data collected were analysed using a combination of ANOVA and multiple linear regression models. Mean MOR and MOE ranged from 4.02 to 12.74 N/mm2 and 2040 to 4060N/mm2 respectively, while (WA), (TS) and (LE) ranged from 27.13 to 43.97%, 0.51 to 3.50% and 0.14 to 0.72% respectively. Strength (MOR) and stifness (MOE) of the boards increased as water pre-treatment temperature were raised from 35°C to 80°C. As water pre-treatment temperature was raised from 80°C to 95°C, weaker and inferior boards were produced. Water pre-treatment temperature was weakly correlated with MOR, MOE, WA, TS and LE. On the other hand, cement/wood mixing ratio was well correlated with these board properties. The study thus demonstrated that there is optimum water pretreatment temperature range (65°C-80°C) within which high quality boards can be produced in the selected species; and beyond which board quality will be impaired.Item Static bending and moisture response of cement-bonded particleboard produced at different levels of percent chemical additive content in board(Faculty of Agriculture, University of Uyo, Nigeria, 2012) Badejo, S.O.; Omole, A. O.; Fuwape, J. A.; Oyeleye, B. O.A study was carried out to determine the optima level of percent additive concentration for wood cement board production from mixed tropical hardwoods species. Eight hardwood species used for the study are: Triplochiton scleroxylon K. Schum (Obeche). Terminalia ivorensis A. Chev. (Idigbo) Terminalia superb Eng. & Diets (Afara) Bruchystegia nigerica Hoyle & A.P.D. Jones (Okwen) Khaya ivorensis A. Chev. (Lagos Mahogany) Nesogordonia papaverifeni A. Chev. (Dantu-Oro) Tectona grandis Linn. F. (Teak) Gmelina arborea Roxb. (Gmelina). The experimental boards were made at five chemical additive content levels of 1.00%: 1.50%: 2.00%: 2.50% and 3.00% based on dry weight of cement in board, and three cement/wood mixing ratio levels of 2.25: 1.0. 2.50: 1.0 and 2.75:1.0. The experimental design is a two-factor factorial experiment, a combination of which manifested in 15 treatment combinations. The mean moduli of Rupture and Elasticity (MOR and MOE) obtained for each of the 15 treatment combinations in this experiment ranged from 3.28 to 10.46 N/mm2 while MOE values ranged from 2200 to 4010 N/mm2. The mean percent water absorption (WA) values ranged from 24.66 to 46.37% while the thickness swelling (TS) ranged from 0.98 to 3.62%. Statistical analysis showed chemical additive concentration and wood/cement ratio were found significant at 1% level of probability on the flexural and moisture properties. Stronger, stiffer and more dimensionally stable boards were produced at increasing levels of these two production variables. Also percent chemical additive content in board of 3.0% (Based on dry cement weight in board) performed best.