Effects of the Surface Roughness of Six Wood Species for Furniture Production on the Wettability and Bonding Quality of Coating

Abstract

Wood surface roughness, surface free energy (SFE), wettability, and bonding quality for water-based acrylic coatings were investigated. The samples tested in this study included Pinus radiata, Pinus sylvestris, Larch, Hemp oak, Catalpa tree, and Camphor. Sandpaper with grits of 180, 240, 320, 400, and 500 was utilized to sand wood surfaces. The van OSS-Chaudhury-Good equation (vOCG) was used to calculate the SFE values. The modified model (M-D) was used to calculate the wettability based on the contact angle change rate (K value). The higher the K value, the faster the contact angle approaches equilibrium. A cross-cut test was used to evaluate the coating’s bonding quality. The anatomical structure of wood has an impact on the roughness of hardwood. The equilibrium contact angle is influenced by the wood species and sandpaper grit size. Sanding can make the surface of wood more wettable. Radiata pine that had been sanded to 180 grit had the highest SFE value. After finishing with waterborne acrylic, hardwood had a slightly better coating adhesion than softwood. Hemp oak wood had the lowest coating adhesion (0.6) and the highest K value (0.82). The best bonding quality (0.4) was supplied by the camphor wood with the lowest K value (0.13). Wettability in terms of K values was a good indication of determining the bonding quality of the water-based acrylic coatings.

The Influence of the Content of Recycled Natural Leather Residue Particles on the Properties of High-Density Fiberboards

“…It can be caused due to the presence of the higher roughness, non-smooth and woolly surface of leather, which is significantly different from the right side, which is smooth. The in-time decreasing contact angle, as well as the surface roughness-contact angle relation can be confirmed by [27]. As it has been proven by Gumowska and Kowaluk [28], the contact angle can influence the physical properties of fiberboards.…”

Surface Roughness, Dynamic Wettability, and Interphase of Modified Melamine Formaldehyde-Based Adhesives on Jabon Wood

“…Consequently, the Ra parameter was employed in this investigation to quantify the surface irregularity of Jabon wood. An approach methodology utilizing Ra values has been implemented in prior studies [ 3 , 4 , 5 , 14 , 15 , 39 , 40 ]. The average roughness (Ra) of a profile is calculated by averaging the individual depths and heights (irregularities) of its arithmetic mean elevation.…”

“…The surface roughness measurement of the wood specimens was performed perpendicular to the fiber direction in three different positions ( Figure 1 ) by a diamond tip with a radius of 5 mm, a tracing length of 6 mm, a cut off of 0.8 mm, and a speed of 0.5 mm/s [ 3 , 15 , 32 ]. The arithmetical mean roughness value (Ra) was used to assess the surface roughness level [ 3 , 4 , 11 , 14 , 15 ]. Ra measurements were conducted on tangential (T), radial (R), and semi-radial (T/R) cross-sections of Jabon lumbers, with each kind of lumber being tested over three replicas.…”

“…The contact angle (θ) of an individual drop image was determined using the low-bond axisymmetric drop shape analysis (LB-ADSA) method, provided by the Image-J software (ImageJ 1.46r) [ 34 ]. In contrast to predominant droplet shape analyses, such as the drop-snakes analysis method [ 3 , 4 , 8 ], the LB-ADSA method fails to distinguish between left and right droplet image contours and contact angles. The approach applied by LB-ADSA is that the contact angles on the left and right sides of an object are identical ( Figure 3 ), resulting in a reflection resembling a mirror on both sides [ 34 ].…”

“…Adhesive quality is a critical component that must be meticulously evaluated during the production of laminated timber products [ 1 ]. In the manufacturing of wood products, surface preparation is a critical step preceding the gluing or finishing procedures [ 2 , 3 , 4 , 5 ]. Sanding is a method that is frequently employed in this process.…”