Nobuhisa Okuda, Masatoshi Sato
Finely milled kenaf core as a natural plywood binder
Application of kenaf core powder as a natural plywood binder has been studied. In the first instance, binderless boards made of kenaf core powder and overlaid sugi (Cryptomeria japonica D. Don) veneers resulted in immediate veneer delamination. However, binderless boards were successfully manufactured from sugi wood powder and had an internal bonding strength of 1.69 MPa. The board properties improved with increasing fineness of the raw material, increasing pressing temperature, and increasing board density. Essential prerequisites for binderless adhesion are: (1) particles should be situated close to each other to allow the formation of chemical bonds; and (2) a high pressing temperature is necessary to melt the solid-solid interfaces between the particles and to supply the activation energy for chemical reactions. For successful adaptation of these requirements, the kenaf core powder should have an average particle size of approximately 10 μm, which then mediates close contact between veneers. Plywood bonded with kenaf core powder had an average tensile shear strength of 0.96 MPa with a wood failure rate of 82.1%. Accordingly, vibratory ball milling activates kenaf core and the powder is suitable as a natural plywood binder.
Holzforschung, Walter de Gruyter
Print ISSN: 0018-3830
Volume: 61, 06/2007
Pages: 439 - 444
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