Investigation of the wetting characteristics of medium density fibreboards (MDF) by means of contact angle measurements

Wulf, M.; Netuschil, P.; Hora, Guido; Schmich, P.; Cammenga, Heiko K.

doi:10.1007/s001070050241

Cited by 16 publications

(8 citation statements)

References 4 publications

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“…In low density species, such as alder is, the grain raising is greater and increases the surface roughness, also affecting its wetting characteristics. For any type of coating, a good wetting contributes to a good film performance (Wulf et al 1997). Insignificant differences in adherence were found between samples coated by spraying with 100% UV varnish product (maximum of 1.22 MPa and minimum of 1.14 MPa) (Fig.…”

Section: Resultsmentioning

confidence: 92%

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Some Coating Properties of Black Alder Wood as a Function of Varnish Type and Application Method

Salca¹,

Krystofiak²,

Lis³

et al. 2016

BioResources

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The objective of this study was to evaluate the adhesion strength and glossiness of black alder wood (Alnus glutinosa Gaertn. L.) coated with water-borne and UV varnishes by two application systems. Prior to coating, the samples were prepared by sanding with four combinations of grit size sandpapers, 180 being the final grit. The surface quality of the specimens was measured with a white light profilometer. Any increase in grit size gradually reduced surface roughness, which further influenced the overall coating performance of the samples. UV varnish applied by roller presented higher adhesion strength and gloss as compared to spraying. The specimens varnished with a water-borne finish by spraying exhibited a better adherence to the substrate than those of UV varnished samples by the same method and provided glossiness at 60° geometry in the same range. These results are valuable for the furniture manufacturing industry for generating a better use and efficiency of secondary wood resources in order to achieve value-added products.

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Section: Resultsmentioning

confidence: 92%

“…The roughness of wood surfaces influences the wettability properties of the solid surface and subsequently the film performance (Wulf et al 1997). Rough wood surfaces require more finish than smooth surface substrates (Richter et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Some Coating Properties of Black Alder Wood as a Function of Varnish Type and Application Method

Salca¹,

Krystofiak²,

Lis³

et al. 2016

BioResources

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“…The surface energies of wood grafted with perfluoroalkyl ethanol-MDI mixtures was characterized by measurements of the contact angle θ with time of glycerol with its surface (Kalnins et al 1988;Hora 1994;Boehme and Hora 1996;Vienghou et al 1996;Wulf et al 1997). Values are reported in Table 4.…”

Section: Contact Angle Measurementsmentioning

confidence: 99%

Chemical Modification of Wood with Perfluoralkyl Ethanol and 4,4'-Diphenylmethane Diisocyanate

Engonga¹,

Schneider²,

Gérardin³

et al. 1999

Holzforschung

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IntroductionChemical modifications of wood have been extensively studied during the last years. Such modifications confer to wood new properties like dimensional stability, fire and decay resistance (Rowell 1984). Of all the methods investigated, reactions using isocyanates have received a lot of attention because of their high reactivity towards the hydroxyl groups of the cell-wall polymers (Chen et al. Furthermore, fluorocarbons possess substantial hydrophobic character which reflects the low values of their cohesive energy density and surface energy. Fluorocarbon polymers have been widely studied in recent years for their unique hydrophobic and lipophobic properties (Rao and Baker 1994).This study aimed at determining if treatment of wood with mixtures of perfluoroalkyl ethanol and 4,4′-diphenylmethane diisocyanate (MDI) could enhance properties of modified wood and especially its resistance to swelling by water. Indeed, MDI can be used as a link for grafting perfluoroalkyl ethanol derivatives on wood because it can react with their hydroxyl groups to form urethane bonds (Fig. 1). Such a methodology has already been used (Ellis and Rowell 1989; Ellis 1993) using isophorone diisocyanate and an oligomer phosphonate to increase wood fire resistance. Materials and MethodsSpruce (Picea abies) wood meal was passed through a 115 mesh sieve, washed in a Soxhlet extractor with a toluene/ethanol (2 : 1, v/v) mixture (16 hours), with acetone (8 hours) and dried at 70°C for 2 days.Weighed (m 0 ) and ovendried beech blocks (Fagus sylvatica) (15 × 20 × 50 mm, radial × tangential × longitudinal) were used for dimensional stability and contact angle measurements.Perfluorohexyl ethanol [CF 3 (CF 2 ) 5 CH 2 CH 2 OH; M = 364 g/mol] and a mixture of perfluoroalkyl ethanol [Rf-CH 2 CH 2 OH; Rf: 51 % of C 6 F 13 , 39 % of C 8 F 17 , 6% of C 10 F 21 and 4 % of C 12 F 2 5 ; M = 426 g/mol] were obtained from Elf-Atochem. 4,4′-Diphenylmethane diisocyanate (MDI) was purchased from Aldrich. All chemicals were used as received without further purification. Reaction solvents were appropriately dried and purified before use. Dichloromethane was distilled over calcium hydride and stored over 4 Å molecular sieves. Acetone was dried over calcium chloride, distilled over potassium permanganate and stored over 4 Å molecular sieves.Infrared spectra of wood and modified woods were recorded on a Mattson Genesis FTIR using potassium bromide disks.Microanalyses were performed by the Service Central d'Analyse (CNRS) at Vernaison, France. Chemical modification of woodGeneral methods of preparing spruce meals and beech blocks modified with perfluoroalkyl ethanol -MDI mixtures are described in this section. Reaction of spruce wood meals with perfluorohexyl ethanol -MDI mixturesWood meals were reacted with perfluorohexyl ethanol -MDI mixtures in 4/1, 2/1 and 1/1 mass ratios of perfluorohexyl ethanol -MDI mixtures to dried wood.Wood meal (500 mg) was mixed with MDI (3.25, 1.62 or 0.81 mM; 0.81, 0.40 or 0.20 g respectively for 4/1, 2/1 and 1/1 mass ratios) ...

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“…Their surface properties exhibit high affinity to the bonding quality between the coating and panel surface [11]. Wetting behavior is an important factor [12]. Regardless of what coating is used, good wettability contributes to better mechanical interlocking, molecular-level interactions, and secondary force interactions between the coating film and the wood surface [13].…”

Section: Introductionmentioning

confidence: 99%

Surface Properties of Pine Scrimber Panels with Varying Density

et al. 2019

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Coating quality for scrimber products against exterior conditions is largely dependent on the surface properties. The wettability, morphology, and chemical composition of pine scrimber surfaces were investigated to better understand the surface properties. The scrimber was found to be a hydrophilic material because the water contact angles were less than 90°. The panels with a density of 1.20 g/cm3 had the largest angle change rate (k = 0.212). As the panel density increased, the instantaneous contact angle of each test liquid (i.e., water, formamide, and diiodomethane) on the panels decreased, and so did surface free energy. Panels with higher density showed lower surface roughness. Surface roughness across the wood grain was greater than that along the grain. SEM observations showed the high-density panels had a smoother surface with fewer irregular grooves in comparison with the low-density panels. X-ray photoelectron spectroscopy (XPS) analysis indicated that more unoxygenated groups appeared on the surface of high-density panels.

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Investigation of the wetting characteristics of medium density fibreboards (MDF) by means of contact angle measurements

Cited by 16 publications

References 4 publications

Some Coating Properties of Black Alder Wood as a Function of Varnish Type and Application Method

Some Coating Properties of Black Alder Wood as a Function of Varnish Type and Application Method

Chemical Modification of Wood with Perfluoralkyl Ethanol and 4,4'-Diphenylmethane Diisocyanate

Surface Properties of Pine Scrimber Panels with Varying Density

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