This study investigated the possible use of four agro-forest residues generated in Ghana as an alternative raw material for particleboard manufacture using cassava starch and urea formaldehyde as adhesives. The partic...This study investigated the possible use of four agro-forest residues generated in Ghana as an alternative raw material for particleboard manufacture using cassava starch and urea formaldehyde as adhesives. The particle size of the materials ranged from 0.5 mm to 1.5 mm. An industrial pressing machine was used to press the homogeneous single layer particleboard. Physical and mechanical properties were determined in accordance with ASTM D 1037-06a and ASTM D 7519-11. The results indicate that the density of the particleboards produced ranged from 421 kg/m<sup>3</sup> to 598 kg/m<sup>3</sup>. The water absorption property of the particleboards also ranged from 7.66% to 22.41% and 18.17% to 59.46% for 2-hour and 24-hour immersions respectively. Additionally, the thickness swelling of the particleboards ranged from 3.38% to 5.03% and 9.37% to 21.49% for 2-hour, and 24-hour immersions respectively. The results further indicate that the modulus of elasticity, modulus of rapture, internal bond strength and hardness of the particleboards produced for both cassava starch and urea formaldehyde were adequate. Comparatively, for all the agro-forest materials used for this study, the physical and mechanical properties of the particleboards produced using urea formaldehyde as adhesive was better than those produced using cassava starch as adhesive. It could be concluded that the particleboards produced could be used for indoor applications or interior furnishings, under dry conditions. Additionally, it is recommended that further studies that combine cassava starch and urea formaldehyde as adhesives be conducted, as well as studies on combining <em>Plantain pseudostem</em> and Cacao pod in particleboard production.展开更多
Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue ...Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue for particleboard production. This study assessed the decay resistance of particleboards produced from four agro-forest residues using cassava starch and urea formaldehyde as adhesives. <i><span>Musa paradisiaca pseudostem</span></i><span>, </span><i><span>Theobroma cacao </span></i><span>stem and pod, and sawdust of </span><i><span>Ceiba pentandra</span></i><span> were used for the study. Properties determined were: Weight loss, decay resistance rating and decay susceptibility index. These properties were evaluated after 12 weeks of exposure to </span><i><span>Coriolopsis polyzona</span></i><span> in accordance with ASTM D 2017</span><span>-</span><span>05. The results indicate that the weight loss for </span><i><span>Musa paradisiaca pseudostem</span></i><span> particleboard was least for both urea formaldehyde and cassava starch adhesives. Even though almost all the particleboards produced were classified as resistant or highly resistant to fungi attack, those produced with urea formaldehyde had better decay resistance properties than that of cassava starch. Furthermore, particleboards coated with synthetic polyvinyl lacquer had better resistance to fungi attack than the uncoated ones. At 5% level of significance, the agro-forest residue, adhesive and surface finish as well as their interactions had significant effects on decay resistance of the particleboards produced. It is recommended that further studies which aim at determining the effect of combination of the agro-forest residues and that of urea formaldehyde and cassava starch be conducted to determine their effects on decay properties of particleboards.</span>展开更多
Ni promoted structured plate-type Pt/Nix/a-AlOOH catalysts were developed to enhance the amount of hydroxyl group, therefore improving the catalytic activities for formaldehyde oxidation at room temperature. The analy...Ni promoted structured plate-type Pt/Nix/a-AlOOH catalysts were developed to enhance the amount of hydroxyl group, therefore improving the catalytic activities for formaldehyde oxidation at room temperature. The analyzation results by XRD and HRTEM indicate that two kinds of materials, AlOOH and NiOOH, are detected on the surface of Pt/Nix/a-AlOOH. It can be seen from the result of TG that the hydroxyl group on the catalyst surface increased after Ni was loaded. Furtherly, XPS results show that the percentage of hydroxyl groups which can effectively absorb formaldehyde increases from 36.4% to 72.8% by doping Ni. In addition, the content of Pt0 increased from 27.5% to 45%. The results indicate that optimized Pt1.15/Ni3.1/a-AlOOH has the best catalytic activity with the CO2 conversion is 88% at 25°C and 100% at 40°C, while CO2 conversion over Pt1.2/a-AlOOH is 56% at 25°C and 100% at 100°C respectively. Hence, the Ni promoted plate-type Pt/a-AlOOH possesses high efficiency and it provides a new idea for catalyst design of formaldehyde oxidation.展开更多
文摘This study investigated the possible use of four agro-forest residues generated in Ghana as an alternative raw material for particleboard manufacture using cassava starch and urea formaldehyde as adhesives. The particle size of the materials ranged from 0.5 mm to 1.5 mm. An industrial pressing machine was used to press the homogeneous single layer particleboard. Physical and mechanical properties were determined in accordance with ASTM D 1037-06a and ASTM D 7519-11. The results indicate that the density of the particleboards produced ranged from 421 kg/m<sup>3</sup> to 598 kg/m<sup>3</sup>. The water absorption property of the particleboards also ranged from 7.66% to 22.41% and 18.17% to 59.46% for 2-hour and 24-hour immersions respectively. Additionally, the thickness swelling of the particleboards ranged from 3.38% to 5.03% and 9.37% to 21.49% for 2-hour, and 24-hour immersions respectively. The results further indicate that the modulus of elasticity, modulus of rapture, internal bond strength and hardness of the particleboards produced for both cassava starch and urea formaldehyde were adequate. Comparatively, for all the agro-forest materials used for this study, the physical and mechanical properties of the particleboards produced using urea formaldehyde as adhesive was better than those produced using cassava starch as adhesive. It could be concluded that the particleboards produced could be used for indoor applications or interior furnishings, under dry conditions. Additionally, it is recommended that further studies that combine cassava starch and urea formaldehyde as adhesives be conducted, as well as studies on combining <em>Plantain pseudostem</em> and Cacao pod in particleboard production.
文摘Many factors including depletion of the forest, environmental awareness, and generation of large quantities of agro-forest residues have increased the need to partially or wholly replace wood with agro-forest residue for particleboard production. This study assessed the decay resistance of particleboards produced from four agro-forest residues using cassava starch and urea formaldehyde as adhesives. <i><span>Musa paradisiaca pseudostem</span></i><span>, </span><i><span>Theobroma cacao </span></i><span>stem and pod, and sawdust of </span><i><span>Ceiba pentandra</span></i><span> were used for the study. Properties determined were: Weight loss, decay resistance rating and decay susceptibility index. These properties were evaluated after 12 weeks of exposure to </span><i><span>Coriolopsis polyzona</span></i><span> in accordance with ASTM D 2017</span><span>-</span><span>05. The results indicate that the weight loss for </span><i><span>Musa paradisiaca pseudostem</span></i><span> particleboard was least for both urea formaldehyde and cassava starch adhesives. Even though almost all the particleboards produced were classified as resistant or highly resistant to fungi attack, those produced with urea formaldehyde had better decay resistance properties than that of cassava starch. Furthermore, particleboards coated with synthetic polyvinyl lacquer had better resistance to fungi attack than the uncoated ones. At 5% level of significance, the agro-forest residue, adhesive and surface finish as well as their interactions had significant effects on decay resistance of the particleboards produced. It is recommended that further studies which aim at determining the effect of combination of the agro-forest residues and that of urea formaldehyde and cassava starch be conducted to determine their effects on decay properties of particleboards.</span>
文摘Ni promoted structured plate-type Pt/Nix/a-AlOOH catalysts were developed to enhance the amount of hydroxyl group, therefore improving the catalytic activities for formaldehyde oxidation at room temperature. The analyzation results by XRD and HRTEM indicate that two kinds of materials, AlOOH and NiOOH, are detected on the surface of Pt/Nix/a-AlOOH. It can be seen from the result of TG that the hydroxyl group on the catalyst surface increased after Ni was loaded. Furtherly, XPS results show that the percentage of hydroxyl groups which can effectively absorb formaldehyde increases from 36.4% to 72.8% by doping Ni. In addition, the content of Pt0 increased from 27.5% to 45%. The results indicate that optimized Pt1.15/Ni3.1/a-AlOOH has the best catalytic activity with the CO2 conversion is 88% at 25°C and 100% at 40°C, while CO2 conversion over Pt1.2/a-AlOOH is 56% at 25°C and 100% at 100°C respectively. Hence, the Ni promoted plate-type Pt/a-AlOOH possesses high efficiency and it provides a new idea for catalyst design of formaldehyde oxidation.