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.

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.

Preliminary Research on Manufacturing Technology of Thin Bamboo Veneer Consolidated Composite Floor

2012 ◽  
Vol 503-504 ◽  
pp. 74-77
Author(s):  
Nan Hu ◽  
Xian Jun Li ◽  
Yi Qiang Wu ◽  
Xin Gong Li ◽  
Zhi Cheng Xue
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Bond Strength ◽  
Hot Pressing ◽  
Physical And Mechanical Properties ◽  
Pressing Pressure ◽  
Pressing Temperature ◽  
Decorative Material ◽  
Preliminary Research ◽  
Surface Bond

In this paper, the new bamboo-based consolidated composite floors were fabricated with thin bamboo veneers which used as decoration layers, wear resistant layers, high density fiberboards and equilibrium layers through assembling and scuffing. The effect rules of the composite floor on properties were preliminarily studied by three factors: hot-pressing temperature, pressure and time. The results showed that the wear resistance and surface bond strength of the thin bamboo veneer consolidated composite floor significantly increased with the rise of hot-pressing temperature. In the scope of resources, the effect of hot-pressing pressure and time on properties of the floor is not significant. The optimizing technology is hot-pressing temperature 170°C, pressure 3MPa and time 40s/mm in this study. The thin bamboo veneer consolidated composite floor is an excellent floor decorative material, which has good physical and mechanical properties.

scholarly journals Influence of different sheet compositions and commercial adhesives on the performance of multilaminated plywood

2021 ◽  
Author(s):  
Carine Setter ◽  
Uasmim Lira Zidanes ◽  
Eduardo Hélio de Novais Miranda ◽  
Flávia Maria Silva Brito ◽  
Lourival Marin Mendes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Water Absorption ◽  
Bulk Density ◽  
Phenol Formaldehyde ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Forest Species ◽  
Specific Pressure

Abstract The quality of plywood panels depends on factors such as the forest species and the adhesive used in their production, and understanding the interferences of these factors in the final properties of the plywood is of fundamental importance. The study aimed to develop multilaminate plywood panels with two forest species and two types of adhesive and to evaluate the influences of these factors (forest species and adhesive) on the physical and mechanical properties of the plywood. The panels were produced with sheets of parica and pine with two types of adhesives, urea-formaldehyde and phenol-formaldehyde, with a weight of 150 g/cm². Then, each set was pressed for 10 minutes under a specific pressure of 0.98 MPa at a temperature of 150 °C. Three panels were produced for each type of blade and adhesive, totaling four treatments. The plywood was evaluated for physical properties (humidity, bulk density, and water absorption) and mechanical properties (parallel and perpendicular static flexion and resistance to mechanical shear). The results showed that the forest species had a greater influence on physical and mechanical properties, with the best results being observed for plywood produced with pine. The panels with sheets of parica and phenol-formaldehyde adhesive showed less moisture. The apparent density of the panels should be considered as it positively influenced the mechanical properties and negatively impacted water absorption. It is concluded that the plywood produced can be used for internal and external applications. However, it is indicated for structural purposes as it did not meet the requirements of the NBR 31.000.001/2:2001.

scholarly journals Effect of Soaking/Oven- Drying on Mechanical and Physical Properties of Birch (Betula spp.) Plywood

2021 ◽  
Vol 72 (2) ◽  
pp. 121-129
Author(s):  
Regino Kask ◽  
Harri Lille ◽  
Mihkel Kiviste ◽  
Silver Kruus ◽  
Johann Olaf Lääne
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Phenol Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Thickness Swelling ◽  
Oven Drying ◽  
Mechanical And Physical Properties ◽  
The Face ◽  
European Standards ◽  
Fractional Equation

The objective of this study was to explore some of the physical and mechanical properties of 9-layer birch (Betula spp.) plywood with the addition of phenol-formaldehyde glue, in cases in which the cutting edges of the samples are coated with the damp-proof mastic Fibergum, and in case in which they remain unprocessed (uncoated), following a total of ten cycles of soaking/oven-drying. The properties to be determined were the bending strength (BS), modulus of elasticity in bending (MOE), thickness swelling (TS) and restore dimensions (RD), which were tested according to the European standards (EN). A linear-fractional equation and linear relationship were used for the approximation of any change in the physical and mechanical properties of the samples depending upon the number of soaking/oven-drying cycles. It was shown that the values of the properties investigated were most affected by the first soaking and drying cycle. Thereafter, BS and MOE levels decreased smoothly at a low rate, but the values of TS became stabilised. The BS and MOE values for the wet samples with coated cutting edges were higher than when they were uncoated, as the moisture levels in the former case were lower. After the first soaking of the samples with coated cutting edges, the retention values were as follows: BS at 52.8 % and 66.7 % for the major and minor axes, respectively, with the same applying to MOE at 61.9 % and 64.2 %, while TS was at 105.2 %. To clarify the phenomenon that causes a decrease of the properties, the face plies and edge structures of the initial dry samples and of the samples after the first, second and ninth soaking/oven-drying cycles were studied using the X-Ray technique.Ključne riječi

Influence of Resin Content on Composite Materials Railway Sleepers for Physical and Mechanical Properties

2011 ◽  
Vol 217-218 ◽  
pp. 495-499
Author(s):  
Yue Sun ◽  
Sheng Ling Xiao
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Bending Strength ◽  
Processing System ◽  
Physical And Mechanical Properties ◽  
Resin Content ◽  
Thickness Swelling ◽  
Pressing Temperature ◽  
Pressing Time ◽  
Resol Resin

It studies the influence of resin content on composite materials railway sleepers for physical and mechanical properties,which is for the preparation of composite materials railway sleepers.It used resol resin setting hot pressure at 2.5Mpa, hot pressing temperature at 170°C, pressing time at 5-6min. The results showed that as the resin content increases, the static bending strength (MOR) first increased and then decreased, the internal bond strength (IB) rised, 2h thickness swelling (2h TS) decreased. Through the analysis of experimental data by using DPS data processing system, resin content had a significant impact on 2h TS.It also affected MOR, IB.But it had little effect on measured density (D), water content (W) and impact strength (IL).

scholarly journals Assessing the bending strength and modulus of elasticity in bending of exterior foiled plywoods in relation to their construction

2012 ◽  
Vol 51 (No. 2) ◽  
pp. 76-94
Author(s):  
J. Hrázský ◽  
P. Král
Keyword(s):  
Mechanical Properties ◽  
Regression Analysis ◽  
Correlation Analysis ◽  
Moisture Content ◽  
Surface Treatment ◽  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Institutional Research ◽  
The Given

The paper summarizes results of an institutional research aimed at assessing the bending strength and modulus of elasticity in bending of exterior foiled combined and all-beech plywoods in relation to their construction. A relationship was studied of the plywood construction and selected physical and mechanical properties. In studied sheets, moisture, density, bending strength and modulus of elasticity were analysed along and across the grain of the upper veneer. All measurements were carried out in water-resistant plywoods with surface treatment with a phenolformaldehyde foil 8, 10, 12 and 15 mm thick in combined plywoods and 10, 12, 15 and 18 mm thick in all-beech plywoods. The construction of plywoods significantly influences their quality that is determined particularly by the bending strength and modulus of elasticity. Using regression analysis relationships were demonstrated particularly that with the increasing moisture content of plywoods the bending strength decreased and with the increasing density the bending strength and modulus of elasticity increased. The same trend was also proved in connection with the increasing number of veneers of plywood sheets. Using correlation analysis, combinations of interrelationships of the given properties were statistically tested.

Study on the Bending Mechanical Properties of Bamboo Plywood Used Middle Temperature PF Resine

2011 ◽  
Vol 374-377 ◽  
pp. 1239-1243
Author(s):  
Jan Han ◽  
Yue Zou
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Hot Pressing ◽  
Bending Strength ◽  
Phenol Formaldehyde ◽  
Stress And Strain ◽  
Pressing Temperature ◽  
Study Results ◽  
Load Increase ◽  
Middle Temperature

The bending mechanical properties of bamboo plywood which was glued with phenol formaldehyde (PF) resine were detected and analysised. The study results showed that the differences of the bending strength (MOR)and the elastic modulus(MOE) of bamboo plywood prepared separately within 110-130°C were not large, and MOR and MOE exceeded all the targets ruled by JB/T 156-2004. It was proved that the property of this kind of middle temperature PF resine was very well for using in bamboo plywood. When the load was the same, the differences of the deflection、the stress of the bamboo plywood prepared on the different hot-pressing temperature were very small too, but some differences existed in the those strains，and the strains on the lower sursurface of the boards were larger than those on upper surface. When the load was smaller, The deflection、stress and strain of the boards linearly changed with the load increase, which proved that the bamboo plywood mainly produced elastic deformation under this circumstances.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

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.

The Silorane-based Resin Composites: A Review

2017 ◽  
Vol 42 (1) ◽  
pp. E24-E34 ◽  
Author(s):  
GA Maghaireh ◽  
NA Taha ◽  
H Alzraikat
Keyword(s):  
Mechanical Properties ◽  
Bond Strength ◽  
Clinical Significance ◽  
Physical And Mechanical Properties ◽  
Marginal Adaptation ◽  
Resin Composites ◽  
Restorative Material ◽  
Polymerization Shrinkage ◽  
Tooth Structure

SUMMARY This article aims to review the research done on the silorane-based resin composites (SBRC) regarding polymerization shrinkage and contraction stresses and their ability to improve the shortcomings of the methacrylate-based resin composites (MRBC). Special attention is given to their physical and mechanical properties, bond strength, marginal adaptation, and cusp deflection. The clinical significance of this material is critically appraised with a focus on the ability of SBRC to strengthen the tooth structure as a direct restorative material. A search of English peer-reviewed dental literature (2003-2015) from PubMed and MEDLINE databases was conducted with the terms “low shrinkage” and “silorane composites.” The list was screened, and 70 articles that were relevant to the objectives of this work were included.

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