Improvement of dimensional stability of wood by silica nanoparticles

ABSTRACT

The improving effect of nanoparticles on wood dimensional stability is barely known nowadays. The expected result of the research was the improvement of the dimensional stability through bulk hydrophobization, as a result of impregnation with hydrophobic SiO₂ nanoparticles. Two different wood species, beech (Fagus sylvatica) and scots pine (Pinus sylvestris) were investigated. Two different treatments with silica nanoparticles were used. One treatment was a pure emulsion of modified (hydrophobized) silica nanoparticles (carrier material: ethanol), and another one was modified (hydrophobized) silica nanoparticles in tetrahydrofuran carrier material in combination with polydimethylsiloxane (PDMS) as a bonding agent. PDMS was used to improve the bonding of the silica nanoparticles to the wood structure. The impregnation with nanoparticles was successful. Shrinking and swelling properties decreased by 17–33%, depending on wood species and treatment. Water uptake and equilibrium moisture content decreased significantly as a result of the treatments (40–58%). Application of PDMS did not provide better dimensional stability compared to the treatment without it, however, it resulted in lower equilibrium moisture content and water uptake compared to the basic nano-SiO₂ treatment.

KEYWORDS:

• Hygroscopicity
• nanoparticles
• swelling
• anti-swelling-efficiency
• swelling anisotropy
• water uptake

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Miklós Bak http://orcid.org/0000-0003-4378-7838

Additional information

Funding

This research was supported by the National Research Development and Innovation Office – NKFIH, in the framework of the project OTKA PD 116635 with the title “Improvement of the most important wood properties with nanoparticles”.