Analysis of the Wood-Wetting Process

Liptáková, Eva; Kúdela, Jozef

doi:10.1515/hfsg.1994.48.2.139

Cited by 77 publications

(53 citation statements)

References 6 publications

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“…The analysis was made in the temperature range 20-260°C by the use of open platinum crucibles, helium flow 2 dm 3 /h and heating rate 5°C/min. The adhesive properties of the investigated resin mixture were determined by evaluating the interactions occurring on the wood-adhesive phase boundary: the contact angle was determined by means of the method described by, among others, Liptàkovà and Kúdela (1994Kúdela ( , 2002, Kúdela and Liptáková (2006). To prepare the samples for investigations, the prepared adhesive mixture was applied on one side of the birch boards at a spread rate of 160 g/m 2 .…”

Section: Methodsmentioning

confidence: 99%

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Fumed silica as a filler for MUPF resin in the process of manufacturing water-resistant plywood

Dukarska

Czarnecki

2015

Eur. J. Wood Prod.

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This work examines the effect of applying fumed silica with nanoscopic-size particles as a filling material for melamine-urea-phenol-formaldehyde (MUPF) resin in the process of manufacturing water-resistant plywood. Moreover, this paper investigates the possibility of reducing the amount of MUPF resin mixture used in the process of gluing veneer sheets. Based on the investigations into the reactivity, viscosity and durability of MUPF resin mixture containing various amounts of nanofiller, it was found that the optimum amount of silica that can make the resin suitable for gluing sheets of veneer amounts to 2 PBW per 100 PBW of MUPF resin. The gluing properties for thus mixed resin were determined by measuring the contact angle and determining the parameters of its derivatives, which are an additional criterion for evaluating the gluing properties. The thermal stability was tested with simultaneous use of TG-DSC analysis. The experimental plywood manufactured using optimal nano-SiO 2 was tested in terms of bond quality and mechanical properties according to appropriate standards. The investigations prove that it is possible to apply fumed silica as a filling material for the resin in the process of manufacturing water-resistant plywood. Introducing the above-mentioned amount of fumed silica into the resin makes it possible to increase the activation energy of the cross-linking process of MUPF resin and to optimize the process of gluing the sheets of veneer. Moreover, it is also possible to produce plywood of the required water-resistance with the amount of adhesive mixture reduced by 30 %.

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Section: Methodsmentioning

confidence: 99%

“…In these calculations, based on the data from literature, the following values were employed for free surface energy of water (Liptáková and Kúdela 1994):…”

Section: Methodsmentioning

confidence: 99%

Fumed silica as a filler for MUPF resin in the process of manufacturing water-resistant plywood

Dukarska

Czarnecki

2015

Eur. J. Wood Prod.

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“…With respect to this, obtained results should be regarded with caution in their absolute value, but it should be noted that the objective of this study is to demonstrate the machined of woods surfaces with differently machined processes, so this approach seems to be suitable. Different methods for the determination of equilibrium contact angle that can be used to calculate the surface free energy of wood have been presented (Cao et al 2005;Gindl et al 2004;Jennings et al 2006;Liptakova and Kudela 1994). In this study, the relative equilibrium contact angle (which is the intercept value of the regress line of contact angle values over time, the value at t = 0 was taken to simulate the value of the equilibrium contact angle) was utilized to calculate the surface free energy of the wood samples, because many authors had indicated that the contact angle obtained by this method could evaluated the surface free energy of wood material successfully (Cao et al 2005;Cao and Kamdem 2007;Maldas and Kamdem 1998;Mamiński et al 2009;Nzokou and Kamdem 2004).…”

Section: Determination Of Surface Free Energy Componentsmentioning

confidence: 99%

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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“…Because both the absorption and spreading occur simultaneously, care must be taken to separate these processes. Different methods for determination of equilibrium contact angle and the contact angle used to calculate the surface free energy of wood have been presented (Liptakova and Kudela 1994). In this study, contact angle evolution after the initial wetting was fitted with a linear function, as we assumed that at the transient time of 0 to 0.5 s, spreading is forceful compared with absorption of samples; after that, the spreading and absorption are synchronous, and the function was extrapolated to t = 0.…”

Section: Contact Angle Measurementmentioning

confidence: 99%

“…These characteristics have been studied recently and in the past (Gardner et al 1991;Liptakova et al 1995;Liu et al 1998;de Meijer et al 2000;Wålinder and Strom 2001;Gindl and Tschegg 2002). Contact angle is the most commonly applied method to calculate surface free energy data for solids using various reference liquids, with several different approaches (Fowkes and Mostafa 1978;Liptakova and Kudela 1994;Gindl et al 2001a,b). Many theories have been introduced to describe and measure the surface free energy of materials with applications to wood systems.…”

Section: Introductionmentioning

confidence: 99%

Wettability of Sanded and Aged Fast-growing Poplar Wood Surfaces: I. Surface Free Energy

et al. 2014

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The sanding process influences the surface morphology and chemical components of wood, which are two important factors that influence the surface free energy and wettability of wood. The objective of this study was to investigate the roughness of sanded poplar wood and the effects of sanding and aging on the surface free energy using different methods. The roughness parameter (Ra) decreased as the grit number increased, but no change was evident when the grit number increased from 120 to 240. The contact angle of water on the fresh wood samples decreased as the grit number increased. Fresh wood samples were more easily wetted by water than was the aged wood sample, and the contact angles increased as the surface roughness decreased. The surface free energy of sanded, aged wood obtained by the Zisman method may be unsuitable. For the fresh wood samples, the change of surface free energy and its components were not significantly changed when the grit number was higher than 120; for the aged wood samples, the dispersion component appeared to increase slightly as the grit number decreased. The effect of roughness on the acid/base component, acid component, and base component calculated by the vOCG method was unremarkable. The surface free energy of the wood samples (obtained using the liquid parameters provided by Volpe and Siboni (1997)) can effectively balance the relationship between the acid and base components.

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Analysis of the Wood-Wetting Process

Cited by 77 publications

References 6 publications

Fumed silica as a filler for MUPF resin in the process of manufacturing water-resistant plywood

Fumed silica as a filler for MUPF resin in the process of manufacturing water-resistant plywood

Surface Free Energy and Dynamic Wettability of Differently Machined Poplar Woods

Wettability of Sanded and Aged Fast-growing Poplar Wood Surfaces: I. Surface Free Energy

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