Significance of the Acidity of Wood to the Surface Free Energy Components of Different Wood Species

Gindl, Milojka; Tschegg, Stefanie

doi:10.1021/la011696s

Cited by 34 publications

(28 citation statements)

References 34 publications

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“…The results obtained for the surface free energy of eucalyptus wood according to the Owens-Wendt model are presented in table 5. The values obtained for the total surface free energy were comparable with those obtained for other hardwoods [6,7]. On the other hand, it was higher for the loose side of the veneers than for the tight side, which is in accordance with the lower contact angles obtained for the former in the wetting study of eucalyptus veneers with tannin solutions.…”

Section: Confocal Laser Scanning Microscopy (Clsm)supporting

confidence: 87%

“…On the other hand, it was higher for the loose side of the veneers than for the tight side, which is in accordance with the lower contact angles obtained for the former in the wetting study of eucalyptus veneers with tannin solutions. In both cases, although more significantly for the tight side, the dispersive component was higher than the polar one which is habitual in most polymers [6]. These differences in the surface free energy between both sides of the veneers indicated that the rotary-peeling process might have altered wood surfaces in different way influencing wettability.…”

Section: Confocal Laser Scanning Microscopy (Clsm)mentioning

confidence: 86%

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Surface characterization of rotary-peeled eucalyptus veneers by confocal laser scanning microscopy and surface free energy and contact angle determination

Vázquez

González‐Álvarez

Freire

et al. 2009

WIT Transactions on Engineering Sciences

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Eucalyptus wood wettability was studied using aqueous solutions of chestnut shell and eucalyptus bark tannins as potential components of wood adhesives. The behaviour of both sides of rotary-peeled veneers, the tight and the loose sides, was analysed and lower equilibrium contact angles were found on the loose side, reflecting a higher wettability. In order to evaluate if rotary-peeling had provoked any surface modification responsible of the observed wettability behaviour, the free surface energy of the veneer tight and loose sides was determined using the Owens-Wendt and the van Oss-Chaudhury-Good models. The higher surface free energy values for the loose side justified the better wettability previously obtained. Confocal Laser Scanning Microscopy (CLSM) allowed obtaining topographical images of the material surface, without sample damage, and calculating the crack length and depth together with various roughness parameters. Significant differences between both sides of the veneers have not been found but CLSM has turned out to be a high resolution technique for material surface characterization.

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Section: Confocal Laser Scanning Microscopy (Clsm)supporting

confidence: 87%

Section: Confocal Laser Scanning Microscopy (Clsm)mentioning

confidence: 86%

Surface characterization of rotary-peeled eucalyptus veneers by confocal laser scanning microscopy and surface free energy and contact angle determination

Vázquez

González‐Álvarez

Freire

et al. 2009

WIT Transactions on Engineering Sciences

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“…For all of the wood investigated (except the rotary wood), the total surface free energy ranged from 60 mJ/m 2 to 70 mJ/m 2 , which was higher than the data given in the literature; many authors have found that the surface free energy of wood ranges from 40 mJ/m 2 to 60 mJ/m 2 (Gardner 1996;Gindl and Tschegg 2002;Little et al 2013). This may be caused by two reasons: the acquired method of contact angle used to calculate the surface free energy and differences in used reference liquids.…”

Section: Surface Energy Componentsmentioning

confidence: 68%

Surface Free Energy and Dynamic Wettability of Differently Machined Poplar Woods

Qin¹,

Gao²,

Zhang³

et al. 2014

BioResources

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The surface free energy and dynamic wettability of wood are important to the performance of its adhesive bonding strength. In this work, the surface free energy of poplar wood samples machined with different processes were calculated by the OWRK (geometric mean) and vOCG (acid-base) methods, and the dynamic wettability of adhesives on wood samples was studied using the S-D wetting model. The results indicate that the contact angles of reference liquids on rotary wood samples were greater than those on planed or sawn wood, and the rotary wood samples were more hydrophobic. The effect of surface roughness on contact angle was insignificant compared with surface structure morphology. The total surface free energy was almost the same for the planed and sawn wood, as calculated by the OWRK and vOCG methods, and the surface free energy of rotary wood samples was lower than that of planed or sawn wood samples. The initial and equilibrium contact angle increased as the viscosity of adhesive increased for all the wood samples, and the contact angles of rotary wood samples were greater than those of planed or sawn wood; however, the K-value was lower. The wettability of the loose side was higher than that of the tight side. Contact angles decreased when surface free energy increased, while the K-value increased.

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“…Also the chemical characteristics of wood surfaces and wood fi bres may vary depending on species and treatment (de Meijer et al 2000 ;Gindl and Tschegg 2002 ;Peterlin et al 2010 ). Thus a method is needed, which is independent of the infl uence of these additional parameters.…”

Section: Introductionmentioning

confidence: 99%

Determination of adhesive energy at the wood cell-wall/UF interface by nanoindentation (NI)

et al. 2012

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Spruce wood specimens were surface-silylated according to three different protocols in order to progressively reduce hydrophilicity and, consequently, adhesion to urea-formaldehyde (UF) glue. Compared to the untreated reference, the macroscopic adhesive strength was drastically reduced in silylated specimens. Specimens treated with the most effective silylation method in terms of reduction of hydrophili city showed near zero adhesion to UF glue. Micromechanical characterisation by means of nanoindentation (NI, Berkovich-type probe) revealed that the wood cell wall stiffness and hardness was not signifi cantly affected by silylation. Contrarily, NI experiments (conical indenter tip with 60 ° opening angle) performed directly at the interface between the wood cell wall and the adhesive showed signifi cantly reduced hardness and reduced specifi c work of NI in silylated specimens. It is concluded that the measured correlation between reduced hydrophilicity in silylated specimens and the mechanical strength of the interface is due to reduced adhesion. This allows calculating the specifi c adhesive energy for the system wood cell wall -urea formaldehyde glue from the difference between the specifi c work of adhesion obtained from the unmodifi ed reference and the most effi ciently silylated specimen. The advantage of this new method lies in the position-resolved measurement of qualitative differences in adhesive energy directly at the interface. This is not feasible with macroscopic test methods, which also include effects of surface roughness, cellular adhesive penetration, or grain angle.

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Significance of the Acidity of Wood to the Surface Free Energy Components of Different Wood Species

Cited by 34 publications

References 34 publications

Surface characterization of rotary-peeled eucalyptus veneers by confocal laser scanning microscopy and surface free energy and contact angle determination

Surface characterization of rotary-peeled eucalyptus veneers by confocal laser scanning microscopy and surface free energy and contact angle determination

Surface Free Energy and Dynamic Wettability of Differently Machined Poplar Woods

Determination of adhesive energy at the wood cell-wall/UF interface by nanoindentation (NI)

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