Composite wood products
Reza Jazayeri; Saeed Kazemi Najafi; Habibollah Younesi
Abstract
This study aimet at to use modified graphite materials as a multifunction additive in the UF resin for improving the properties of medium density fiberboard (MDF). For this purpose expanded graphite EG was synthesized from graphite using the Tsai et al (2011) method. Then, as-synthesized EG was intercalated ...
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This study aimet at to use modified graphite materials as a multifunction additive in the UF resin for improving the properties of medium density fiberboard (MDF). For this purpose expanded graphite EG was synthesized from graphite using the Tsai et al (2011) method. Then, as-synthesized EG was intercalated with manganese dioxide by Schwarz et al (1995) method and converted to MnO2-EG. Any additive was added to the urea formaldehyde resin in three doses of 1, 2 and 3% to make the relevant MDF panels with 750 kg/m3 nominal density. During the pressing time, the tT100oc parameter (time to reach temperature100○C) of the middle layer of the board under the influence of the additive was determined by a chromium-nickel-based thermocouple. The treatment of MnO2-EG3 (amount of 3% modified expanded graphite) showed the greatest effect in reducing tT100°C of the middle layer of the board by 22%. In addition, the elastic modulus increased by 68% as a result of this treatment. In addition, the elastic modulus increased by 68% as a result of this treatment. G and EG additives showed a higher degree of internal adhesion than that of MnO2-EG additive. In this regard, EG2 and EG3 treatments showed a 42% increase in internal adhesion and G2 treatment showed a 40% increase in internal adhesion. The effect of EG2 treatment in improving SW24 was greater than other treatments, so that it caused a 19% decrease compared to the control.
Reza Jazayeri; saeed kazemi najafi; Habibollah Younesi; Abolfazl Kargarfard
Abstract
In this study, the effect of graphite and two modified graphite materials in reducing formaldehyde emission of medium density fiberboard (MDF) was investigated. For this purpose, expanded graphite (EG) was syntesyzed from graphite (G) and modified expanded graphite (MnO2-EG) was produced through the ...
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In this study, the effect of graphite and two modified graphite materials in reducing formaldehyde emission of medium density fiberboard (MDF) was investigated. For this purpose, expanded graphite (EG) was syntesyzed from graphite (G) and modified expanded graphite (MnO2-EG) was produced through the intercalation process of expanded graphite with manganese dioxide. Thus, three graphite materials were prepared for resin treatment. Molecular tests including X-ray diffraction (XRD) and X-ray diffraction spectroscopy (SEM-EDS) were performed to determine their molecular properties,. In addition, the differential scanning caliber test (DSC) test was performed to evaluate the thermal behavior of the resin under the influence of these graphite materials as additive. The additives were added to urea formaldehyde resin at three levels of consumption of 1, 2 and 3%, and then medium density fiberboard (MDF) with a density of 750 kg/m3 was made from glued fibers. After making the board, the formaldehyde emission test was performed by desiccator method. Overall, MnO2-EG showed better results than control and two other graphite treatments. The best performance was resulted by MnO2-EG at level 3% so that reduced formaldehyde emission by about 61%. It seams the formaldehyde molecules absorbed into the expanded graphite layers were exposed to oxidation by manganese dioxide molecules. On the other hand, as the DSC test showed, the highest anthalopy reaction occurred in resin treated by MnO2-EG, indicating an increase in the reaction of formaldehyde molecules in the resin structure.
