Adhesive strength and micromechanics of wood bonded at different moisture contents
Source abstract
Abstract
The adhesive bonding of wood is preferably carried out at levels of moisture content close to those expected during service. In this study, the influence of non-ideal wood moisture content (MC) during adhesive bonding is investigated, using lap shear testing, nanoindentation and microscopy. Spruce lamellas were bonded at 5, 12, 25% MC and largely above fiber saturation point (∼55% MC) with melamine-urea-formaldehyde (MUF) and one-component polyurethane adhesive (1C PUR). Tensile shear strength decreased with increasing MC for both adhesive systems, even though the specimens were given ample time to post-cure, as testing was at standard MC 12%. Particularly above FSP, with the presence of free water, tensile shear strength was significantly reduced. For MUF, this is consistent with reduced mechanical properties measured with nanoindentation presuming that excessive moisture hindered adhesive cure. For 1C PUR, micromechanical properties of the bulk adhesive were not significantly affected by MC, the influencing factor was rather insufficient adhesion to the wood surface due to free water. The results propose the applicability of the adhesive beyond the recommended moisture ranges, but advise caution when bonding wood above FSP without process adjustments.
Source: openalex_inverted_index · Quality: baseline
Research context
OpenAlex topics: Wood Treatment and Properties · Natural Fiber Reinforced Composites · Material Properties and Processing
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (42)
Show source-provided references
1. Effects of surface ageing on wettability, surface chemistry, and adhesion of wood10.1007/s00107-004-0471-4 ↗
2. A review of surface and interfacial adhesion in wood science and related fields10.1007/BF00351806 ↗
3. Technological performance of formaldehyde-free adhesive alternatives for particleboard industry10.1016/j.ijadhadh.2019.04.007 ↗
4. Mechanical properties of adhesives for bonding wood - a review10.1016/j.ijadhadh.2013.03.013 ↗
5. Surface chemical composition and roughness as factors affecting the wettability of thermo-mechanically modified oak (Quercus robur L.)10.1515/hf-2018-0022 ↗
6. Marra · 1992
7. Penetration of liquid urea-formaldehyde adhesive into beech wood
8. Wood adhesion and adhesives
9. Adhesive penetration in wood - a review
10. Understanding wood bonds - going beyond what meets the eye: a critical review10.7569/RAA.2018.097312 ↗
11. Siau · 1995
12. Adhesive groups and how they relate to the durability of bonded wood10.1163/156856108X379137 ↗
13. Water in wood: a review of current understanding and knowledge gaps10.3390/f13122051 ↗
14. 2013
15. 2014
16. Influence of cure conditions on the properties of a one-component moisture-cured polyurethane adhesive in the context of green gluing of wood10.1002/app.36895 ↗
17. Influence of moisture on stress–strain behaviour of adhesives used for structural bonding of wood10.1016/j.ijadhadh.2013.01.015 ↗
18. The performance of adhesive systems for structural timbers10.1016/S0143-7496(97)00010-9 ↗
19. Einfluss der Holzfeuchte und ausgewählter technologischer Parameter auf die Verklebung mit 1K-PUR Klebstoffen unter extremen klimatischen Bedingungen10.1007/s00107-005-0088-2 ↗
20. The role of wood extractives in structural hardwood bonding and their influence on different adhesive systems10.1016/j.ijadhadh.2019.03.001 ↗
21. Low temperature and moisture dependent curing behavior of selected wood adhesives10.1016/j.ijadhadh.2022.103178 ↗
22. Bonding performance of melamine-urea-formaldehyde and phenol-resorcinol-formaldehyde adhesives in interior grade glulam10.1080/01694243.2017.1313185 ↗
23. Effects of moisture content on lap-shear, bending, and tensile strength of lap-jointed and finger-jointed southern pine using phenol resorcinol formaldehyde and melamine urea formaldehyde10.15376/biores.15.2.3534-3544 ↗
24. Effects of hot-pressing parameters on resin penetration
25. Application of the ultrastructure concept in industrial wood products research
26. 2013
27. 2013
28. Adhesive penetration of wood cell walls investigated by scanning thermal microscopy (SThM)10.1515/HF.2008.014 ↗
29. Mechanical characterisation of wood-adhesive interphase cell walls by nanoindentation10.1515/HF.2006.067 ↗
30. Comparing dry bond strength of spruce and beech wood glued with different adhesives by means of scarf- and lap joint testing method10.1007/s00107-006-0104-1 ↗
31. Structure-property relationships in one-component polyurethane adhesives for wood: sensitivity to low moisture content10.1002/app.24334 ↗
32. Wood/adhesive interactions and the phase morphology of moisture-cure polyurethane wood adhesives10.1016/j.ijadhadh.2011.12.009 ↗
33. Niemz · 2017
34. Survey of selected adhesive bonding properties of nine European softwood and hardwood species10.1007/s00107-016-1087-1 ↗
35. Mechanical properties of wood adhesive bond lines tested in service classes according to Eurocode 510.1016/j.ijadhadh.2022.103233 ↗
36. Investigations on the characterization of various adhesive joints by means of nanoindentation and computer tomography10.3390/ma15238604 ↗
37. Adhesive strength and micromechanics of wood bonded at low temperature10.1016/j.ijadhadh.2020.102697 ↗
38. Elastic properties of adhesive polymers. III. Adhesive polymer films under dry and wet conditions characterized by means of nanoindentation10.1002/app.32342 ↗
39. The effect of moisture on the mechanical response of wood, adhesive and their interphase by means of nanoindentation10.1007/s00226-019-01100-4 ↗
40. Moisture related elastic and viscoelastic behaviour of wood adhesives by means of in-situ nanoindentation10.1016/j.ijadhadh.2018.06.004 ↗
41. Adhesive bonding and performance testing of bonded wood products
42. Adhesive systems for structural connections in timber10.1016/S0143-7496(00)00049-X ↗