Decay Resistance of Particleboards Manufactured with Four Agro-Forest Residues Using Cassava Starch and Urea Formaldehyde as Adhesives

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. Musa paradisiaca pseudostem, Theobroma cacao stem and pod, and sawdust of Ceiba pentandra 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 Coriolopsis polyzona in accordance with ASTM D 2017-05. The results indicate that the weight loss for Musa paradisiaca pseudostem 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.

The effect of urea pretreatment on the formaldehyde emission and properties of straw particleboard

For manufacturing low-formaldehyde emission particleboard from wheat straw and urea-formaldehyde （UF） resins using urea treatment for indoor environments, we investigated the influence of urea treatment on the formaldehyde emission, physical and mechanical properties of the manufactured particleboard. Wheat straws were treated at three levels of urea concentration （5%, 10%, 15%） and 95℃ as holding temperature. Wheat straw particleboards were manufactured using hot press at 180℃ and 3 MPa with two types of UF adhesive （UF-45, UF-91）. Then the formaldehyde emission values, physical properties and mechanical properties were considered. The results show that the for- maldehyde emission value was decreased by increasing urea concentration. Furthermore, the results indicate that the specimens under urea treatment have better mechanical and physical properties compared with control specimens. Also specimens under urea treatment at 10% concentration and UF-91 type adhesive have the most optimum physical and mechanical strength.

Effects of Planting Density of Rubber Tree Clone(RRIM 2020 Clone and RRIM 2025 Clone)Wood to Particleboard Properties

The depletion of log resources encourages research into alternative ways to sustain the wood supply.Therefore,the 4-year-old Rubber Research Institute of Malaysia(RRIM)clones series,RRIM 2020 and RRIM 2025,were chosen as potential raw materials for particleboard in this study.The purpose of this study was to assess the effects of planting density and rubber tree clones on the mechanical and physical properties of single-layer particleboard.The planting densities used were low,moderate-low,moderate-high,and high,representing 500,1000,1500,and 2000 trees/ha,respectively.Prior to manufacturing,the RRIM 2000 series clone trees were harvested,cut,chipped,flaked,and screened.The mechanical and physical properties were evaluated in accordance with the Japanese Industrial Standard(JIS A 5908-2003).The findings revealed that both planting density and clone had a significant impact on the mechanical and physical properties of particleboard with a thickness of 10 mm and a density of 700 kg/m3.RRIM 2020 specimens with low planting density had superior modulus of elasticity(MOE),modulus of rupture(MOR),and internal bonding(IB)values of 2415,19,and 1.7 MPa,respectively.Furthermore,moderate-low planting density demonstrated the lowest thickness swelling(TS)and water absorption(WA)values and was comparable to control particleboard from commercial clone Prang Besar(PB),PB260.In terms of rubber clones,RRIM 2020 particleboard met the minimum requirements of the JIS standard for mechanical properties and outperformed RRIM 2025.This study recommended a low planting density of 500 trees/ha and the RRIM 2020 clone as a suitable raw material for particleboard manufacturing with a ten percent urea formaldehyde resin content.

Characterization of Particleboard Produced from Residues of <i>Plantain pseudostem</i>, Cacao Pod and Stem and <i>Ceiba</i>

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/m3 to 598 kg/m3. 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 Plantain pseudostem and Cacao pod in particleboard production.