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An aluminophosphate adhesive was used as the binder in plywood. The hot-pressing parameters of aluminophosphate adhesive-based plywood (APPs) including hot-press temperature (A), time (B), and pressure (C) were optimized using response surface methodology. Results indicated that the hot-press temperature was the most dominant factor. The maximum bonding strength of 1.98 MPa was found with an optimal parameter of 171 °C (hot-press temperature), 7.5 min (hot-press time), and 1.0 MPa (hot-press pressure). Additionally, the chemical reaction mechanism between aluminophosphate adhesive and wood fibers was characterized by X-ray photoelectron spectroscopy (XPS). Results showed that good interaction was generated between wood fibers and adhesives through their surface functional groups. In conclusion, the optimized pressing conditions of plywood significantly improved bonding strength of APPs. [ABSTRACT FROM AUTHOR]

In order to optimize its production technology, response surface methodology (RSM) was used to optimize the hot-pressing process during the preparation of chitosan-modified starch adhesive film. Ranges of hotpressing temperature, hot-pressing time, and adhesive consumption were selected based on single-factor tests. A quadratic regression model of the bonding strength was obtained by fitting the response value of the bonding strength of the plywood. The results showed that the adhesive consumption and the hot-pressing temperature had a significant effect on the bonding strength of the adhesive. Also, the interaction between the temperature, time, and adhesive consumption were significant. The optimum hot-pressing process parameters for chitosan-modified starch adhesive film were a hot-pressing temperature of 145.2 °C, a hot-pressing time of 182.7 s, and an adhesive consumption of 239.3 g/m². The predicted values of the quadratic regression model fit well with the actual values of the stability test. [ABSTRACT FROM AUTHOR]

Selected physical and mechanical properties of cement bonded board produced from Gliricidia sepium were assessed. The following board properties were evaluated, water absorption, thickness swelling, water absorption and thickness swelling following accelerated aging, modulus of rupture and modulus of elasticity. The Board formation was based on cement: wood ratio 1:1, 2:1 and 3:1, board densities of 800, 900 and 1000kg/m3 on dry weight basis. The quantity of cement, particles, and water for the production of each board was weighed, mixed separately and very well in order to prevent the formation of particles lumps. Blended mixture was transferred and formed inside a nominal mould dimension of 650mm in length, 650mm in width and 13mm thickness on a caul plate that was covered with polythene sheet before plywood was laid at the top of the mat. The mean value for water absorption and thickness swelling ranged from 3.06 to 6.99% and 1.40 to 7.51%, respectively. Following accelerated aging test, water absorption and thickness swelling ranged from 3.41 to 8.12% and 3.46 to 15.58%, respectively. The mean values for Modulus of rupture (MOR) ranged from 0.76 to 10.22N/mm2 while the mean values for Modulus of Elasticity (MOE) of the experimental boards produced ranged from 1800.77 to 5220.60N/mm2. Water absorption and thickness swelling decreased with increase in board density and cement: wood ratio. After the board had been subjected to accelerated aging, water absorption and thickness swelling of the boards decreased with increase in density and cement: wood ratio. Modulus of rupture and modulus of elasticity increased with increase in board density and cement: wood ratio. Gliricidia sepium was found suitable for the production of cement bonded board. [ABSTRACT FROM AUTHOR]

The dimensional stability of Gmelina arborea wood was investigated using the modified greenhouse dryer. Daily temperature and relative humidity patterns in the Greenhouse and air-dry shed were assessed to determine their influence on the moisture variation, density, volumetric shrinkage and volumetric swelling of Gmelina arborea after drying for 40 days. Wood samples were obtained from a twenty-year old plantation at the Federal University of Technology, Akure. For laboratory work, 45 freshly cut samples of 20mm x 20mm x 60mm were dried in the oven at 105°C for 24 hours until they attained constant weight while for field experiment, 45 freshly cut samples of 25mm x 75mm x 450mm Gmelina arborea wood were loaded into the Greenhouse dryer and air-dry shed respectively. The result obtained for average daily temperature and relative humidity pattern in the greenhouse for the period was 31.17°C and 77.29% respectively while 22.47°C and 84.57% were recorded for air drying shed. The attainable moisture content for Green house dryer after 40 days of drying was found to be 19.05% while air-dry medium was 31.46% which showed that greenhouse medium dried the wood below fibre saturation point, a better performance over air drying method. Wood samples of Gmelina arborea in the Greenhouse dryer were found to be more stable in terms of swelling and shrinkage attained. The result of the overall mean density for Gmelina arborea wood was found to be 463.89kg/m³ which classified the wood as non-refractory because of its low density. [ABSTRACT FROM AUTHOR]