Wood bonding by mechanically-inducedin situ welding of polymeric structural wood constituents

Gfeller, B.; Properzi, M.; Zanetti, M.; Pizzi, A.; Pichelin, Frédéric; Lehmann, Martin; Delmotte, L. (2004). Wood bonding by mechanically-inducedin situ welding of polymeric structural wood constituents Journal of Applied Polymer Science, 92(1), pp. 243-251. Wiley 10.1002/app.13648

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Mechanically induced wood fusion welding, without any adhesive, is shown here to yield rapidly bonding wood joints satisfying the relevant 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 amorphous cells–interconnecting polymer material in the structure of wood, mainly lignin, but also some hemicelluloses. This causes a partial detachment, the “ungluing,” of long wood cells and wood fibers and the formation of an entanglement network drowned in a matrix of melted material which then solidifies, thus forming a wood cell/fiber entanglement network composite with a molten lignin polymer matrix. During the welding period some of the detached wood fibers which are no longer being held by the interconnecting material are pushed out of the joint as excess fiber. Crosslinking chemical reactions of lignin and carbohydrate‐derived furfural also occur. Their presence 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 relatively longer 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 BFH Centres and strategic thematic fields > BFH Centre for Wood - Resource and Material
Name:	Gfeller, B.; Properzi, M.; Zanetti, M.; Pizzi, A.; Pichelin, Frédéric0000-0003-3856-6707; Lehmann, Martin0000-0002-0813-7023 and Delmotte, L.
Subjects:	Q Science > Q Science (General) T Technology > T Technology (General) T Technology > TA Engineering (General). Civil engineering (General)
ISSN:	0021-8995
Publisher:	Wiley
Language:	English
Submitter:	Sally Haddad
Date Deposited:	12 May 2020 11:34
Last Modified:	18 Dec 2020 13:30
Publisher DOI:	10.1002/app.13648
Uncontrolled Keywords:	wood welding wood fusion polymer melting adhesives lignin joints
URI:	https://arbor.bfh.ch/id/eprint/11537