scholarly journals Effects of the thickness of rotary-cut veneers on properties of plywood sheets. Part 2. Physical and mechanical properties of plywood materials

2012 ◽  
Vol 52 (No. 3) ◽  
pp. 118-129
Author(s):  
J. Hrázský ◽  
P. Král
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Institutional Research ◽  
Nominal Thickness

The second part of the paper summarizes results of an institutional research aimed at the determination of physical and mechanical properties of different sets of plywood sheets pressed under different conditions. The first part dealt with the determination of compressibility or values of decreasing the thickness of pressed plywood sheets. In this second part, results are summarized of the analysis of physical and mechanical properties of the set of whole-beech plywood sheets of the nominal thickness of veneers amounting to 1.5 mm. The plywood sheets were manufactured as seven-ply and urea-formaldehyde resin DUKOL S was used for their production. The sheets were pressed using a pressure of 1.5 and 1.7 MPa. Following parameters were analyzed: moisture, density, bending strength, MOE in bending and shear strength.

STUDY OF THE INFLUENCE OF STABILIZERS ON THE PROPERTIES OF CARBAMIDE FOR-MALDEHYDE BINDER AND FC PLYWOOD

2020 ◽  
Vol 10 (1) ◽  
pp. 136-143
Author(s):  
A. Fedotov ◽  
Tat'yana Vahnina ◽  
Andrey Titunin ◽  
Aleksandr Sviridov
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Strength Reduction ◽  
Cohesive Strength ◽  
Urea Formaldehyde Resin ◽  
Strength Characteristics ◽  
Formaldehyde Resin ◽  
Glycerol Mono

The problem of stabilizing the properties of the urea-formaldehyde binder during storage is relevant for both glued products and resins. Changing the performance of the resin during storage makes it difficult to apply a binder and leads to a deterioration in the physical and mechanical properties of plywood. The effect of glycerol, mono- and triethanolamine, as well as a mixture of glycerol and monoethanolamine on the nominal viscosity of the resin after 56 days of storage, has been studied. The use of glycerol and monoethanolamine (including in the complex) reduces the nominal viscosity of the resin by 13.5-24.8%. The use of triethanolamine as a stabilizer makes it possible to reduce the nominal viscosity by 35% in comparison with the index of an unstabilized oligomer. Mechanical properties of FC plywood based on the stabilized and unstabilized binder has been studied. It was found that glycerol additive (or glycerol in combination with monoethanolamine) significantly reduces strength characteristics of plywood, which makes it irrational to use these stabilizers. The addition of 0.2% triethanolamine to CFS allows a 35% reduction in the nominal viscosity of the resin, while the cohesive strength of the binder decreases by 1.5%. The result is within the framework of the dispersion of the indicator, i.e. strength reduction is negligible. The static bending strength of plywood with a stabilized triethanolamine binder is more important than that of control specimens without the addition of stabilizers. The results of the study enable to recommend the addition of triethanolamine in an amount of 0.2% by weight of urea-formaldehyde resin as a rational stabilizer

scholarly journals Effects of the thickness of rotary-cut veneers on properties of plywood sheets. Part 1. Compressibility of plywood materials

2012 ◽  
Vol 51 (No. 9) ◽  
pp. 403-411
Author(s):  
J. Hrázský ◽  
P. Král
Keyword(s):  
Economic Evaluation ◽  
Urea Formaldehyde ◽  
Urea Formaldehyde Resin ◽  
Production Costs ◽  
Formaldehyde Resin ◽  
Institutional Research ◽  
Production Parameters ◽  
A Value

The paper summarizes results of the institutional research aimed at the determination of compressibility or values of the reduction of thickness of compressed plywood sheets. Assessing the effect of thickness and thickness tolerances of veneers to a value of compressibility in relation to production parameters was carried out on the collection of plywood whole-beech sheets of the nominal veneer thickness of 1.5 mm. The plywood sheets were manufactured as seven-ply ones and urea-formaldehyde resin DUKOL S was used for their manufacture. Following characteristics were assessed: thickness differences, size of shrinkage, compressibility of veneers. Sheets were pressed using a pressure of 1.5 and 1.7 MPa. Values of changes in the thickness of veneers in pressed veneer sheets and coefficients of compressibility of particular properties were then statistically analyzed. Basic economic evaluation was carried out of the effect of compressibility on the amount of production costs.

scholarly journals AVALIAÇÃO DO POTENCIAL DE USO DE ESPÉCIES DE PÍNUS TROPICAIS E EUCALIPTO NA PRODUÇÃO DE PAINÉIS COMPENSADOS UREICOS

FLORESTA ◽  
2012 ◽  
Vol 42 (2) ◽  
pp. 277 ◽  
Author(s):  
Setsuo Iwakiri ◽  
Felipe Gustavo Sanches ◽  
Daniele Cristina Potulski ◽  
Janice Bernardo Silva ◽  
Mário De Andrade ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Pinus Taeda ◽  
Urea Formaldehyde ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Eucalyptus Species ◽  
Pressing Time ◽  
Potential Use

Esta pesquisa teve como objetivo avaliar a qualidade dos painéis compensados multilaminados produzidos a partir de lâminas de madeira de cinco espécies de pínus tropicais e nove espécies de eucalipto. Foram produzidos em laboratório painéis compensados com cinco lâminas de 2,0 mm de espessura, coladas com resina ureia-formaldeído (UF), com gramatura de 360 g/m². Os painéis foram prensados com pressão específica de 10 kgf/cm², temperatura de 110 ºC e tempo de prensagem de 7 min. Foram avaliadas as propriedades de resistência da linha de cola aos esforços de cisalhamento (RLC), teste seco e úmido e flexão estática (MOE e MOR) paralela e perpendicular. Entre as espécies de pínus tropicais, o P. oocarpa e P. tecunumannii foram as que apresentaram melhor desempenho. Já para as espécies de eucalipto, os melhores resultados foram obtidos para E. saligna, E. viminalis e E. dunnii. Todas as espécies de pínus tropicais e de eucalipto avaliadas neste estudo apresentaram resultados de propriedades mecânicas estatisticamente iguais ou superiores em relação à espécie referencial – Pinus taeda. Os resultados obtidos indicam a viabilidade de uso de lâminas dessas espécies para fabricação de painéis compensados para uso interior.Palavras-chave: Lâminas de madeira; compensados; pínus tropicais; eucalipto. AbstractEvaluation of potential use of species of tropical pine and eucalyptus for UF plywood manufacture. This research was developed in order to evaluate the quality of plywood manufactured from veneers of five species of tropical pine and nine species of eucalyptus. The plywood was manufactured with five veneers of 2.0 mm thickness, using urea-formaldehyde resin with amount of glue spread of 360 g/m². The boards were pressed at pressure of 10 kgf/cm², temperatures of 110 ºC and pressing time of 8 minutes. It was evaluated the properties of glue line shear strength (RLC) and static bending (MOE and MOR), parallel and perpendicular. Among tropical pine species, P. oocarpa and P. tecunumannii presented the best results in relation to mechanical properties of the boards. For the eucalyptus species  best results were obtained by E. saligna, E. viminalis and E. dunnii. All the  tropical pine and eucalyptus species evaluated in this research presented boards mechanical properties statistically equal or greater when compared to referential species - Pinus taeda. The results revealed the feasible use of such species veneers for plywood manufactures to internal applications.Keywords: Veneers; plywood; tropical pine; eucalyptus.

scholarly journals Effects of different pressing conditions on properties of spruce plywoods

2012 ◽  
Vol 52 (No. 6) ◽  
pp. 285-292 ◽  
Author(s):  
P. Král ◽  
J. Hrázský
Keyword(s):  
Mechanical Properties ◽  
Bond Strength ◽  
Shear Test ◽  
Bending Strength ◽  
Phenol Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Institutional Research ◽  
Specific Pressure ◽  
Pressing Temperature ◽  
Nominal Thickness

The paper presents results of an institutional research aimed at assessing the effect of different technological conditions in pressing on physical and mechanical properties of plywood sheets. Spruce plywood sheets of the veneer nominal thickness of 3.0 and 3.5 mm were analyzed. The plywood sheets were produced as five-ply and BAKELITE PF B118 phenol-formaldehyde adhesives were used for there manufacture. In relation to a different pressing temperature 115, 120 and 125°C and a different specific pressure, density, bending strength, MOE in bending and glue-bond strength by a shear test were assessed. The determined values of properties were statistically tested.

Glutardialdehyde Modified Corn Starch – Urea Formaldehyde Resin as a Binder for Particleboard Making

2015 ◽  
Vol 754-755 ◽  
pp. 89-93 ◽  
Author(s):  
M.H.M. Amini ◽  
R. Hashim ◽  
N.S. Sulaiman ◽  
S. Hiziroglu ◽  
Othman Sulaiman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elasticity Modulus ◽  
Corn Starch ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Urea Formaldehyde Resin ◽  
Modulus Of Rupture ◽  
Formaldehyde Resin ◽  
Japanese Industrial Standard ◽  
Internal Bonding Strength

The objective of the study was to characterize and to evaluate physical and mechanical properties of experimental particleboard panels made from rubberwood (Heveabrasiliensis) using modified starch-urea formaldehyde as binder. Panels were manufactured using 13% corn starch modified with glutardialdehyde with addition of 2 % urea formaldehyde resin and tested for their physical and mechanical properties. All of the particleboards satisfied the Japanese Industrial Standard which required 2000 N/mm2, 8.0 N/mm2and 0.15 N/mm2for modulus of elasticity, modulus of rupture and internal bonding strength, respectively. The mechanical properties were comparable to those made using 15 % urea formaldehyde resin with reduction of formaldehyde fume was over 50 %.

scholarly journals Eco-Friendly, High-Density Fiberboards Bonded with Urea-Formaldehyde and Ammonium Lignosulfonate

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 220
Author(s):  
Petar Antov ◽  
Viktor Savov ◽  
Ľuboš Krišťák ◽  
Roman Réh ◽  
George I. Mantanis
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
High Density ◽  
Thickness Swelling ◽  
Formaldehyde Content ◽  
Uf Resin ◽  
Natural Wood ◽  
European Standards

The potential of producing eco-friendly, formaldehyde-free, high-density fiberboard (HDF) panels from hardwood fibers bonded with urea-formaldehyde (UF) resin and a novel ammonium lignosulfonate (ALS) is investigated in this paper. HDF panels were fabricated in the laboratory by applying a very low UF gluing factor (3%) and ALS content varying from 6% to 10% (based on the dry fibers). The physical and mechanical properties of the fiberboards, such as water absorption (WA), thickness swelling (TS), modulus of elasticity (MOE), bending strength (MOR), internal bond strength (IB), as well as formaldehyde content, were determined in accordance with the corresponding European standards. Overall, the HDF panels exhibited very satisfactory physical and mechanical properties, fully complying with the standard requirements of HDF for use in load-bearing applications in humid conditions. Markedly, the formaldehyde content of the laboratory fabricated panels was extremely low, ranging between 0.7–1.0 mg/100 g, which is, in fact, equivalent to the formaldehyde release of natural wood.

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