The wettability and surface free energy of sawn, sliced and sanded european oak wood

Abstract

The main objective of this work was to evaluate the effects of two machining processes on European oak wood surface characteristics. The relationships between wettability, free surface energy and machining methods were studied. Sawing and slicing, with or without sanding, were used to prepare surfaces prior to testing whether they produce surfaces with different characteristics. For the wood surfaces machined by slicing and sawing, there was a significant difference in contact angle measurements. This indicates that the influence of machining processes such as slicing and sawing on contact angle value is remarkable. Sanded surfaces showed good wettability and high process roughness.

The influence of mechanical surface preparation methods on southern pine and spotted gum wood properties: Wettability and permeability

“…The lowest mean contact angle and therefore highest surface wettability varied depending upon time frame after surface machining; however, the surface machining methods-80 grit sanding post-planing (SM7), 40 grit sanding post-planing (SM6), and face milling with fast feed/slow cutter speed (SM2) performed similarly, producing high wettability compared to other surface machining methods. This result is in line with numerous studies which report that the rougher surface produced by sanding or face milling improves the wettability of wood compared to planing (Stehr et al 2001;Aydin 2004;Hernández and Cool 2008;Arnold 2010;Huang et al 2012;Kläusler et al 2014;Qin et al 2015;Jankowska et al 2018). Stehr et al (2001) attributed the improved wettability of rougher surfaces to the increased surface area, which facilitates the movement and penetration of liquids due to capillary forces.…”

Influence of mechanical surface preparation methods on the bonding of southern pine and spotted gum: Tensile shear strength of lap joints

“…Face milling and sanding treatments have been shown, in other studies using different species, to result in higher roughness and fibrillation and differences in the levels of sub-surface cell damage compared to planing (Knorz et al 2015). Higher wood surface roughness and fibrillation have been shown to increase the wood wettability and bonding strength through the facilitation of adhesive spreading by improved capillarity, an increased surface area for mechanical adhesion, and an increased exposure of hydrophilic sites for the adhesive to bond to (Hernández and Cool 2008a;Santoni and Pizzo 2011;Kläusler et al 2014;Knorz et al 2015;Qin et al 2014;Jankowska et al 2018). Fibrillation is reported to improve wood adhesive bond performance by fortifying the adhesive layer and creating a more homogenous strain dissipation in the glue-line (Knorz et al 2015).…”

Effects of Anatomical Characteristics and Wood Density on Surface Roughness and Their Relation to Surface Wettability of Hardwood

“…Fibre wall thickness (r 2 = 0.803), surface roughness (r 2 = 0.800) and density (r 2 = 0.744) were the most influential factors that affected surface wettability of wood. Surface wettability is highly dependent on density and surface roughness of wood (Nadir et al 2010, Rolleri et al 2016, Agnieszka et al (2018. Lumen diameter, fibre length, fibre and vessel diameter did not exert any significa influence of surface wettability of wood.…”