Wood bonding by vibrational welding

Gfeller, B.; Zanetti, M.; Properzi, M.; Pizzi, A.; Pichelin, Frédéric; Lehmann, Martin; Delmotte, L. (2003). Wood bonding by vibrational welding Journal of Adhesion Science and Technology, 17(11), pp. 1573-1589. 10.1163/156856103769207419

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Mechanically-induced wood welding, without any adhesive, is shown here to rapidly yield wood joints satisfying the relevent requirements for structural application. The mechanism of mechanically-induced vibrational wood fusion welding is shown to be due mostly to the melting and flowing of some amorphous, cells-interconnecting polymer material in the structure of wood, mainly lignin, but also hemicelluloses. This causes partial detachment, the 'unglueing' of long wood cells, wood fibres, and the formation of a fibre entanglement network in the matrix of molten material which then solidifies. Thus, a wood cells/ fibre entanglement network composite having a molten lignin polymer matrix is formed. During the welding period some of the detached wood fibres which are no longer held by the interconnecting material are pushed out of the joint as excess fibres. Cross-linking chemical reactions also have shown to occur. The most likely one of these identified by NMR appears to be a cross-linking reaction of lignin with carbohydrate-derived furfural. The presence of these reactions has been identified by CP-MAS 13C-NMR. These reactions, however, are relatively minor contributors during the very short welding period. Their contribution increases after welding has finished, which explains why long holding times under pressure after the end of welding contribute strongly to obtaining a good bond.

Item Type:	Journal Article (Original Article)
Division/Institute:	School of Architecture, Wood and Civil Engineering School of Architecture, Wood and Civil Engineering > Institute for Materials and Wood Technology BFH Centres and strategic thematic fields > BFH Centre for Wood - Resource and Material
Name:	Gfeller, B.; Zanetti, M.; Properzi, M.; Pizzi, A.; Pichelin, Frédéric0000-0003-3856-6707; Lehmann, Martin0000-0002-0813-7023 and Delmotte, L.
Subjects:	Q Science > Q Science (General) Q Science > QC Physics Q Science > QD Chemistry T Technology > TA Engineering (General). Civil engineering (General) T Technology > TJ Mechanical engineering and machinery
ISSN:	0169-4243
Language:	English
Submitter:	Frédéric Pichelin
Date Deposited:	21 Apr 2020 14:43
Last Modified:	09 Nov 2022 10:02
Publisher DOI:	10.1163/156856103769207419
Uncontrolled Keywords:	Adhesives Joints Lignin Polymer melting Wood fusion Wood welding
URI:	https://arbor.bfh.ch/id/eprint/11263