Scratch resistance of PEG-impregnated green wood: a method for evaluation of swollen wood properties

Stefania Fortino, Jarkko Metsäjoki, Helena Ronkainen, Ingela Bjurhager, Sabine Heinemann, Lauri I. Salminen

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)


This work proposes an experimental approach to study the scratch resistance of green wood under the effect of polyethylene glycol (PEG) impregnation. To this end, small-scale green spruce samples are stabilized against water by using the technique of PEG impregnation to prevent water to seep out of the wood during experimental tests. Scratches are performed in the radial-longitudinal and tangential-longitudinal planes of cubic wood samples by using two different indenter tips under constant and progressive normal loads. Scratch testing has previously been used mainly to characterize the abrasion resistance of coatings. Since PEG simulates the swelling effect of water in wood, this paper shows that the scratch tests on PEG-impregnated green wood can be adopted as a simple technique to understand the scratch resistance in swollen wood and the related mechanisms. The scratch test results, quantified in terms of frictional forces and permanent residual depths, reveal that the scratch resistance of wood samples depends on their PEG concentration and density, as well as on the indenter tip size and material, and on the normal force and direction during scratching. Due to the lack of literature on the scratch tests of wood, the results presented in this paper will serve as a scientific reference for future studies on the scratch resistance of untreated or treated dry wood and other wood-based products.
Original languageEnglish
Pages (from-to)715-735
JournalWood Science and Technology
Publication statusPublished - 25 Apr 2020
MoE publication typeA1 Journal article-refereed


Open access funding provided by Technical Research Centre of Finland (VTT). The scratch tests and confocal laser scanning microscopy were funded by the VTT MultiDesign Innovation Programme. The analysis of results was supported, in part, by the project DigiMoist1 (A Digital end-user toolset for Moisture assessment in Wooden buildings, 1st part: Hygro-thermal database), funded by the Ministry of the Environment of Finland.


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