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Abstract Student ID:M8812014 Title of thesis:Electromagnetic Shielding Wood Veneer Composites Total page:61 Name of Institute:Department of Forestry Graduate date:June, 22 2005 Degree Conferred:Master Name of student:Chen, Ming-Jer Adviser:Lin, Cheng-Jung Huang, Yaw-Fuh The contents of abstract in this thesis: The main purpose of this study was aimed at developing a method for manufacturing electromagnetic interference shielding wood veneer composites (WVC). In the study, the thin film type of electro-conductive materials (copper web, copper foil, aluminum foil and carbon fiber woven cloth) were selected for composing with sawn veneer of wood oil tree and red oak, and with rotary cut veneer of mersawa to fabricate wood veneer composites (WVC), firstly. Then, electro-conductive powder of carbon black, ferric oxide, copper powder, aluminum powder and bamboo charcoal powder prepared with different carbonization temperature of 900, 1100, 1300 and 1500℃ were applied to replace of wheat flour in the glue formulation. And, three types of veneer mentioned above were used to fabricate WVC again. Finally, the physical properties and electromagnetic interference shielding properties of WVC were evaluated, also. The results show that the MOR, MOE and impact strength of WVC which was composed with the thin sheet of electro-conductive material and mersawa rotary cut veneer or red oak sawn veneer were enhanced but the one of wood oil tree. The electromagnetic interference shielding effectiveness (insertion loss) of the WVC composed with one sheet of the thin electro-conductive material and mersawa veneer has the largest insertion loss value from 30-40 dB between the measuring frequency range of 1.5-2.7 GHz. Meanwhile, the WVC composed with two sheets of metal materials has higher electromagnetic interference shielding effectiveness (about 40-60 dB). But, the return loss of WVC mentioned above was very small. Therefore, the mechanism of electromagnetic interference shielding effectiveness of those materials was to reflect the wave back, not to absorb them. The physical properties of LVL bonded with glue which was formulated with UF and electro-conductive powder instead of wheat flour are not influenced at all as the filler dosage between the general level of 10 to 20%. As for the electromagnetic interference shielding effectiveness of this type of LVL, the insertion loss is increased with the filler dosage and larger than that of the controlled one. The return loss is decreased with the filler dosage and smaller than that of the controlled one.
Key words: Insertion loss, return loss, wood veneer composites, electromagnetic interference shielding effectiveness.
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