WOOD RESEARCH Volume 69, Number 4, 2024
SINTA AMANAH, RESA MARTHA, EFRIDA BASRI, MAHDI MUBAROK, ISTIE SEKARTINING RAHAYU, IRSAN ALIPRAJA, WAYAN DARMAWAN, PHILLIPPE GÉRARDIN, LUKAS EMMERICH, HOLGER MILITZ, and UMMI HANI ABDULLAH

THE EFFECT OF WEATHERING ON SURFACE CHARACTERISTICS OF CHEMICALLY MODIFIED SCOTS PINE (PINUS SYLVESTRIS) WOOD

Scots pine (Pinus sylvestris L.) sapwood of 200 × 20 × 80 mm3 (L×R×T) was treated with both cell wall filling and lumen filling chemical agents (low-molecular phenol-formaldehyde, bio-oil, N-methylol/N-methyl compounds, sorbitol-citric acid, polysiloxane), which were fixed inside the wooden structure during heat-curing processes. The present study investigated the impact of the appointed chemical modifications on the surface characteristics of wood, which was addressed by measurements of the surface roughness (Ra), surface free energy (SFE), contact angles, wettability and its bonding quality. Independent of the chemical agents applied, Ra decreased as result of the chemical treatments, while SFE experienced a reduction. The Ra and SFE of both untreated and modified pine specimens increased after weathering processes. The weathering was appointed to cause a decrease in the equilibrium contact angle (θe) and an increase in the constant contact angle change rate (K-value). Increasing K-values after weathering for both untreated and modified pine specimens indicated their better wettability. Increasing wettability after weathering led to better adherence of acrylic paints on the surface of the Scots pine wood. In summary, the chemical modifications decreased the Ra and SFE of the pine sapwood, which may as a consequence affect the wettability and bonding quality of wood during outdoor exposure

WOOD RESEARCH Volume 69, Number 2, 2024
AYBERK AYDOGMUS and NIHAT SAMI CETIN

CHANGE IN SOME ACOUSTIC PROPERTIES OF WOODS USED IN MUSICAL INSTRUMENTS AFTER CHEMICAL MODIFICATION WITH PROPIONIC ANHYDRIDE

The spruce (Picea orientalis), maple (Acer pseudoplatanus), sapele (Entandrophragma cylindricum), cypress (Cupressus sempervirens) and mulberry (Morus alba) woods, which are among the wood types commonly used in making musical instruments, were subjected to chemical modification by propionic anhydride for 1 h, 3 h and 6 h reaction times. The changes in dimensional stability, sound velocities, modal frequencies and dynamic elasticity modulus values of wood samples after modification were investigated. According to the results obtained, as the weight gain values occurring depending on the reaction time increased, the dimensional stability increased in all wood types. When the acoustic properties were examined, it was determined that individual changes occurred at different values depending on the wood type and chemical modification times

WOOD RESEARCH Volume 61, Number 4, 2016
Vlastimil Borůvka, Aleš Zeidler, and Stanislav Doubek

Impact of silicon-based chemicals on selected physical and mechanical properties of wood

This study deals with the impact of silicon-based chemicals on selected physical and mechanical properties of wood. Wood of European beech and Scots pine was the testing material used for impregnation using water glass and commercial product Lukofob EVO 50. The impact of the treatment on dimensional stability, bending strength and modulus of elasticity was tested. Wood density was also evaluated. Although the modification using silicon-based staffs resulted in a statistically significant decrease in swelling for both of the tested species, the positive effect of the treatment was accompanied by a decrease in the strength and stiffness of wood. Water glass had a stronger effect on the tested properties from the chemicals we used in our research.

WOOD RESEARCH Volume 62, Number 2, 2017
Miao Ye

Effect of wood modifiers on the physical properties of fast- growing poplar wood

Investigate the wood modifilers effect on the physical properties of fast-growing poplar wood. Wood modifier was applied to impregnation drying operation on fast-growing poplar, and the characteristics of poplar wood before and after modification were observed with X-ray diffractometer (XRD), scanning electron microscope (SEM), energy-dispersive spectrometer and Fourier transform infrared (FTIR) spectrophotometer to analyze the physical properties of the wood. The modification could significantly improve physical properties of the poplar wood. XRD data illustrated that wood modifier could reduce crystallinity of wood from 39.65% to 36.89%. The findings of energy-dispersive spectrometer indicated that nitrogen (N), oxygen (O) and carbon (C) were evenly distributed in the wood. SEM spectrum analyzed the distribution of wood modifier in the wood pores. The FTIR spectra proved that there was cross-linking reaction between the modifier and the internal parts of the wood, and the amount of hydroxyl decreased sharply.

WOOD RESEARCH Volume 63, Number 4, 2018
Stanislav Doubek, Vlastimil Borůvka, Aleš Zeidler, and Ladislav Reinprecht

Effect of the passive chemical modification of wood with silicon dioxide (silica) on its properties and inhibition of moulds

This work investigates how wood modification with silicon dioxide affects its selected physical and mechanical properties and resistance to moulds. Silicon mineralization can improve some of the technical properties of wood and extend the service-life of wooden structures. Silicon, which is contained in inorganic and organic-inorganic substances that are used for artificial wood mineralization or is the main component at natural wood mineralization, was used in the form of colloidal silicon dioxide and its various concentrations for pressure impregnation of beech (Fagus sylvatica) and Silver fir (Abies alba) wood samples. Following, physical, mechanical and biological properties of such modified woodswere tested together with waterlogged fir wood stored in water over a long period. Silicon-dioxide did not significantly improve properties of beech and fir woods, probably due to the hypothesis, that none covalent bonds between the silicon and the OH- groups of cellulose, hemicelluloses or lignin could be created in the cell-walls of the silicon-modified woods.