Declining availability of the prime economic species in the Nigerian timber market has led to the introduction of Lesser-Used Species (LUS) as alternatives. Their acceptability demands information on the technical properties of their wood. The aim of this study was to investigate the mechanical properties of Ficus vallis-choudae to determine its potential for timber. Three mature Ficus vallis-choudae trees were selected and harvested from a free forest area in Ibadan, Oyo State, Nigeria. Samples were collected from the base (10%), middle (50%), and top (90%) along the sampling heights of each tree, which was further partitioned into innerwood, centrewood, and outerwood across the sampling radial position. Investigations were carried out to determine the age, density, moisture content, impact strength, modulus of elasticity, modulus of rupture, compressive strength parallel-to-grain, and shear strength parallel-to-grain. The mean impact bending strength, modulus of rupture, modulus of elasticity, maximum shear strength parallel-to-grain, and maximum compression strength parallel-to-grain for Ficus vallis-choudae at 12% moisture content were 20.4 N/mm2, 85.8 N/mm2, 709 N/mm2, 10.7 N/mm2, and 33.6 N/mm2, respectively. The study found the species to be dense with high strength properties in comparison with well-known timbers used for constructional purposes.
Ethanol, water and ethanol/water mix were used to directly liquefy Detarium senegalense bark at 500°C for 15 min. Ethanol/water mix at 50/50% weight by weight showed synergistic effect on biomass direct liquefaction, and was found to be the most effective solvent for the liquefaction of Detarium senegalense bark. Water was more active than Ethanol when both mono-solvents were evaluated. Liquefaction with 100% water yielded 46% by weight of the bio-oil, compared with 30% by weight of bio-oil yield when 100% ethanol was used. The result however, show that 50% ethanol/water showed a synergistic effect and work best to obtain 52% bio-oil on the liquefaction whereas water was found hence more active than ethanol as a single solvent with 46% and 30% bio-oil respectively. The GC-MS analysis of the obtained bio-oils from the three matrices confirmed the presence of phenolic compounds and aromatics such as benzenes, followed by aldehydes, long chain ketones and cyclic ketones and alcohol, esters, organic acids and ether compounds. The detected phenolic compounds were 4-ethyl-guaiacol, 2-methoxy-4-(2-propenyl)-phenol, 2-methoxy-phenol, and 2-methoxy-4-vinyl-phenol., formed from the cleavage of guaiacyl and hydroxyphenyl-type lignin with varying degrees of alcohol substitution. Understanding and evaluating the liquefied products obtained from hardwood barks, could offer valuable information on the utilization of the biomass-liquefaction products for chemical or energy production.
Bio-phenol formaldehyde (BPF) resole resins were characterized by liquid-state 13C Nuclear Magnetic Resonance (NMR) spectroscopy. The liquid 13C NMR analysis indicated that the condensation reactions between the bark phenolic compounds and the formaldehyde occurred during the synthesis of the resins. Methylene ether bridges in the resins were more pronounced in the BPF resin when compared to the PF resin system. The liquid-state 13C NMR study revealed significant differences in the resins structures induced by the inclusion of bark-phenolic components. The bark-phenolic components favored the formation of para-ortho methylene linkages in the BPF resins and also enhanced the cure rate of the BPF resin system.
Polyethylene composites reinforced with wood dust from Ceiba pentandra were produced at one proportional variable of wood to polymer ratio. The polymers employed for the study were derived from recycled polyethylene embalmed dihydrogene monoxide bags. Derived homogenous particlesize of 1.00 mm of wood and polyethylene particles were used for production at ascending varying percentage of 40, 50, and 60 for wood and at descending varying percentages of 60, 50, and 40 for polyethylene. The effects of Coptotermes curvignathus attack on weight and mechanical properties of wood polyethylene composites were investigated while the extent of damages was examined. The properties which include weight, density, flexural modulus, flexural strength, compressive strength were determined before and after field exposure. The percentage weight changes were also determined after 12 weeks of graveyard field exposure. The mechanical values obtained before and after termite attacks ranged from 781.03 Kg/cm3 to 810.60 Kg/cm3 for density, 1087.76 Nmm− 2 to 4320.02 Nmm− 2 for flexural modulus, 43.68 Nmm− 2 to 59.14 Nmm− 2 for flexural strength and 18.43 Nmm− 2 to 32.55 Nmm− 2 for compressive strength. The density of the wood polyethylene composites was found to be at peak values when the wood content was at 40% while polyethylene content was at 60%. The wood polyethylene composites made at equal percentage of 50/50 was found to be at lowest values for all properties accessed both before and after termite exposures. The proportional percentage of wood/ polyethylene significantly affects the outcome of weight, density, flexural modulus and compressive strength of the composites after exposure to graveyard under tropical climate. This study revealed that the WPC products can be classified as very durable and durable while WPC at proportional ratio of 40/60 can be adopted for house application in Nigeria.
Nigerian Anacarddiacea family was investigated in this study on the account of their inherent structures with a view to bringing to the fore those features that could facilitate identification towards proper utilization based on wood quality. Mature wood species of Lannea grandis, Lannea welwitchii, Mangifera indica, Nothospondis staudtia, Pseudospondias microcarpa, Sclerocarya burrea, Sorindeia trimeris, Spondias mangifera, Spondias mombin and Trichoscypha acuminate were got from the Forestry Research Institute of Nigeria herbaratum, in Ibadan. Wood samples from the wood species were sectioned into cross sectional, tangential and radial sections of about 20µm thick using a Reichert sliding microtome. Photomicrographs were taken using a digital camera mounted on a Reichert light microscope at 40 ×. The results showed that vessels were large in all the wood species except in Lannea species, Sclerocarya burrea, Nothospondis staudtia and Trichoscypha acuminata. Body ray cells were procumbent with one row of upright and/or square marginal cells in all the wood species, but could be up to four rows in Sorindeia trimeris. Generally, septate fibres, silica,crystals and gum were observed in almost all the wood species, yet, fibre pits in Mangifera indica, Nothospondis staudtia, Pseudospondias microcarpa, Sclerocarya burrea, Spondias mombin, and L. grandis were not as bordered as they were in L. acida, L. welwitchii, Sorindeia trimeris, Spondias mangifera, and Trichoscypha acuminata. S..mombin and S. mangifera can be separated on this account. It also appears that rays were storied only in Sorindeia trimeris and L. grandis. In the aspect of wood utilization, some were expected to possess fine texture, lustrous patterns and also regions of failures as a result of high rays.
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