Papers by Keyword: Urea-Formaldehyde

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Authors: Yong Shun Feng, Shi Hua Chen, Jun Mu
Abstract: Products from pyrolysis of wood-based composites contain lots of valuable chemicals. The nitrogen compounds make such pyrolysis products different from those of general biomass. In this study, we characterized pyrolysis liquids and solid residues of waste wood-based composites such as particle board (PB) and medium density fiberboard (MDF). The study focuses mainly on the evolution of nitrogen compounds. Thermogravimetric analysis helped us to determine the optimum pyrolysis temperature. FTIR analysis was used to observe functions of nitrogen compounds in the solid residues. Components of pyrolysis liquids were analyzed by gas chromatography mass spectroscopy (GC-MS). Changes of FTIR spectrum indicate that C-N groups are reduced during pyrolysis process. Results from GC-MS analysis show that pyrolysis liquids are influenced a lot by the nitrogen compounds transferred from urea formaldehyde. Such changes will guide the utilization of pyrolysis products from waste wood-based composites.
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Authors: Polphat Ruamcharoen, Jareerat Ruamcharoen
Abstract: Nowadays, formaldehyde is considered to be a hazardous volatile chemical. One of the formaldehyde sources is urea-formaldehyde resin which is mainly used as an adhesive in particleboard production. Hence, it is necessary to minimize the formaldehyde residue from urea-formaldehyde synthesis. This present work involves the kinetic modelling of urea-formaldehyde polymerization to predict formaldehyde concentration during the pre-polymerization process. On the basis of previous proposed mechanism, the kinetic model which accounted for the number of the functional groups on urea and formaldehyde and also reactive polymer chains was developed as a set of ordinary differential equations (ODEs). The formaldehyde concentrations from computer simulation results were compared with those from experimental investigation. Good agreement between simulation and experimental results was obtained. The developed kinetic model can be also applied to predict the functional group evolution during polymerization. This helps producers select the condition for production to minimize formaldehyde residue and predict the chemical structure of final product.
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Authors: Nur Afidah Abu Bakar, Suhaimi Muhammed
Abstract: The study involving utilization of agricultural residue is gaining attention. This is an attempt to investigate the possibility of producing composite panels from rice husk (RH), an abundant source of agricultural residues. Composite panels were produced by mixing 1mm of rice husk with a commercial binder called urea formaldehyde at different density levels namely 650kg/m3, 700kg/m3 and 750kg/m3. Two types of resin content (10% and 12%) were used. Mechanical strength tests were performed on the panels conforming to British Standard (BS EN 310). Results obtained indicated that the modulus of elasticity (MOE) increased up to 1753.98MPa at 750kg/m3 density level with 12% resin content. Similarly, modulus of rupture (MOR) increased up to 8.08MPa with increase in panel density and amount of resin content. Thus, the potential of producing reasonably good composite panels from rice husk for specific end usage is very promising.
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Authors: Tay Chen Chiang, Sinin Hamdan, Mohd Shahril Osman
Abstract: Every year, the sago processing industry in Sarawak-Mukah had generated huge amount of sago waste after the milling process and scientists have employ the waste into composite material. The fabrication and testing method are based on the Japanese A5908 Industrial Standard. Single-layer particleboards with targeted density of 600kg/m3 were produced from different sizes of sago particles. The mechanical properties of sago waste were investigated to study the feasibility of using this sample as a raw material in particleboard manufacturing. The results of the test demonstrate that samples with different sizes of particles have great influence on the mechanical properties such as Young’s Modulus, Tensile Strength and Impact Strength. The findings show that the performance of the board is affected by the different sizes of sago particles used in the experiment and had proved that sago plants can be used as an alternative raw material in the particleboard manufacturing industry.
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Authors: Zhen Zhong Gao, Li Tao Guan, Jin Sun, Deng Yun Tu
Abstract: Hexamethoxymethyl melamine (HMMM) was used to modify UF resins to obtain good performance with low formaldehyde emission. The effect of urea to formaldehyde ratio, HMMM content on the properties of UF resin was studied in detail. The results suggested that urea to formaldehyde ratio to be 1:0.9 and 20% HMMM content is the optimum formulation to afford desired UF resin. The viscosity, solidification time, bond strength and formaldehyde emission of the modified UF resins were also studied. The results revealed that the performance of the modified UF achieved the chinese standard.
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Authors: Shu Nan Qiao, Lu Hai Li, Wang Ming, Li Xin Mo
Abstract: To solve the gelatin gum arabic electronic ink microcapsules’ problems of thin shells, easy to break and poor mechanical properties, the above microcapsule was coated by urea-formaldehyde polymer and double shell microcapsule was got. The surface morphology of double shell microcapsules was observed by Metallurgical Microscopy, the dispersion particle size of microcapsules was measured by Laser Particle Size Analyzer, the microcapsules’ hermetization property was tested by UV-Vis spectrophotometer, and the mechanical intensity of microcapsule was measured by Microcomputer Control Omnipotence Test Machine (MCOTM). It was found that the microcapsule prepared by this method showed regular shape and increased size. Additionally, both the hermetization property and mechanic intensity of the microcapsules were improved.
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