Analysis of low requirement justification of the current standard for the strength of wood particle boards

Abstract Currently, wood particle boards made of crushed shavings are widely used in the production of cabinet furniture, despite their shortcomings. The volume of particle board production in Russia is constantly growing. The main disadvantages of the boards include their toxicity associated with the release of gas (formaldehyde) harmful to humans above the permissible level (PL = 0.01 mg/m3 of air), low strength properties (especially bending strength) and limited areas of application of the boards. If we trace the dynamics of the technical requirements for these properties of boards according to the standards, then the question arises - what is the reason for the decrease in the requirements for the strength of boards in bending and, in this regard, the limitation of the application areas of particle board? A regular decrease in the requirements in the newly introduced State Standards has been constantly occurring since 1977, but this is especially noticeable in the current 10632-2014 State Standard. This article focuses on the possible objective and subjective reasons for the low requirements of the current standard for the strength of wood particle board.

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Shungite Nanopowder as a Modificator of Mechanical Properties and Water Absorption for Three-Ply Particle Board

Materials Science Forum ◽

10.4028/www.scientific.net/msf.860.73 ◽

2016 ◽

Vol 860 ◽

pp. 73-77 ◽

Cited By ~ 2

Author(s):

Sergey Borisovich Vasilyev ◽

Gennady Nikolaevich Kolesnikov ◽

Aleksandr Vasilyevich Pitukhin ◽

Nikolai Gennadievich Panov ◽

Vadim Kostyukevich

Keyword(s):

Mechanical Properties ◽

Experimental Investigation ◽

Water Absorption ◽

Bending Strength ◽

Wood Particle ◽

Breaking Point ◽

Experimental Investigations ◽

Formaldehyde Resin ◽

Particle Board ◽

Thickness Swelling

The article presents the methods and the results of the experimental investigation of the additive influence of shungite nanopowder when mixed in the glue for three-ply particle board. The hypothesis of shungite nanopowder influence on physical-mechanical properties, water absorption and thickness swelling of wood particle board was formulated. The results of experimental investigations proved that the optimum shungite nanopowder quantity in glue solution makes up about 10 % of absolutely dry resin mass. Wooden particles of aspen and coniferous species, as well as glue solution based on carbamide-formaldehyde resin, were used in boards manufacturing. The samples were tested in order to determine physical-mechanical properties. It was found out that the 10 % shungite nanopowder additive increases the breaking point of three-ply particle board under bending strength by 18.3-25.7 %, the breaking point of three-ply particle board under tension perpendicular to the face of board by 7.5-11.7 %. As the result of experimental investigation it was found out that the 10 % shungite nanopowder when mixed in the glue decreases water thickness swelling of three-ply particle board up to 14.2 % and water absorption by 10.6-20.1 %. The shungite nanopowder powder contained particles of 50...100 nm in size and specific surface of 120 m2/g. In the course of the experiment three-ply particle boards were used with the thickness of 15.6 mm.

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Particle Board and Oriented Strand Board Prepared with Nanocellulose-Reinforced Adhesive

Journal of Nanomaterials ◽

10.1155/2012/158503 ◽

2012 ◽

Vol 2012 ◽

pp. 1-8 ◽

Cited By ~ 34

Author(s):

Stefan Veigel ◽

Jörn Rathke ◽

Martin Weigl ◽

Wolfgang Gindl-Altmutter

Keyword(s):

Bending Strength ◽

Oriented Strand Board ◽

Urea Formaldehyde ◽

Cellulose Nanofibers ◽

Strength Properties ◽

Particle Board ◽

Adhesive Bonds ◽

Adhesive Mixtures ◽

Scale Particle ◽

Muf Adhesives

Adhesives on the basis of urea-formaldehyde (UF) and melamine-urea-formaldehyde (MUF) are extensively used in the production of wood-based panels. In the present study, the attempt was made to improve the mechanical board properties by reinforcing these adhesives with cellulose nanofibers (CNFs). The latter were produced from dissolving grade beech pulp by a mechanical homogenization process. Adhesive mixtures with a CNF content of 0, 1, and 3 wt% based on solid resin were prepared by mixing an aqueous CNF suspension with UF and MUF adhesives. Laboratory-scale particle boards and oriented strand boards (OSBs) were produced, and the mechanical and fracture mechanical properties were investigated. Particle boards prepared with UF containing 1 wt% CNF showed a reduced thickness swelling and better internal bond and bending strength than boards produced with pure UF. The reinforcing effect of CNF was even more obvious for OSB where a significant improvement of strength properties of 16% was found. For both, particle board and OSB, mode I fracture energy and fracture toughness were the parameters with the greatest improvement indicating that the adhesive bonds were markedly toughened by the CNF addition.

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Anniversary of the first national standards for geodetic instruments

Geodesy and Cartography ◽

10.22389/0016-7126-2019-946-4-20-25 ◽

2019 ◽

Vol 946 (4) ◽

pp. 20-25

Author(s):

O. K. Golubkova ◽

A.I. Spiridonov

Keyword(s):

Public Service ◽

Positive Impact ◽

State Standards ◽

National Standards ◽

Technical Level ◽

Instrument Making ◽

The Public ◽

Technical Requirements ◽

Basic Parameters ◽

Technical Specifications

State standards on the types, basic parameters of levels and theodolites as well as technical requirements were developed in CNIIGAiK in 1962–1963. The authors indicate the experience of developing the first State standards for geodetic instrument making, the difficulties encountered in developers. In this article the main stages of preparation of State standards, including action algorithm from technical specifications to submissions for the approval of the public service are marked step-by-step. The types of levels and theodolites, and the basic technical characteristics for each type are described. During 55 years the positive impact in the areas of production and application of standardized levels and theodolites, inter alia, streamlining the issuance of standard sizes of devices, increased production and improved their quality and technical level was revealed.

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Density, hardness and strength properties of densified fir and aspen woods pretreated with water repellents

Holzforschung ◽

10.1515/hf-2020-0075 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Hüseyin Pelit ◽

Fatih Emiroglu

Keyword(s):

Compression Ratio ◽

Bending Strength ◽

Linseed Oil ◽

Vacuum Treatment ◽

Strength Properties ◽

Aspen Wood ◽

Positive Effect ◽

Water Repellents ◽

Impregnated Wood ◽

Compression Temperature

AbstractIn this study, the effect of thermo-mechanical densification on the density, hardness, compression strength, bending strength (MOR), and modulus of elasticity (MOE) of fir and aspen wood pretreated with water repellents was analyzed. Wood specimens were impregnated with paraffin, linseed oil and styrene after pre-vacuum treatment. Then, the impregnated wood specimens were densified with compression ratios of 20 and 40%, and at 120, 150 and 180 °C. The results indicated that the density, hardness and strength properties of the all densified specimens (untreated and impregnated) increased depending on the compression ratio and temperature. For all tested properties, higher increases were obtained in the paraffin and styrene pretreated specimens compared to untreated samples. However, the increase rates in linseed oil pretreated specimens were generally lower than untreated specimens. Regarding water repellents the most successful results in all tested properties were determined in styrene pretreated specimens. The density, hardness and strength properties of all specimens increased with the increase in compression ratio. On the other hand, the increase in the compression temperature negatively affects the properties of untreated and linseed oil pretreated specimens, while having a generally positive effect on the properties of paraffin pretreated specimens. However, all tested properties of styrene pretreated specimens have increased significantly due to the increase in compression temperature. The increasing strength properties of wood as a result of densification have increased much more with paraffin and especially styrene pretreatment. These combinations can be considered as an important potential for applications that require more hardness and strength.

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Study on Particleboard made from Nipa palm (Nypa fruticans) stem wood and Rajkoroi (Albizia richardiana) wood

Journal of Non Timber Forest Products ◽

10.54207/bsmps2000-2018-qpjp02 ◽

2018 ◽

Vol 25 (1) ◽

pp. 15-18

Author(s):

Md. Mahabubur Rahaman ◽

◽

Khurshid Akhter ◽

S. Hossain ◽

Md. Rakibul Islam ◽

...

Keyword(s):

Tensile Strength ◽

Dimensional Stability ◽

Bending Strength ◽

Strength Properties ◽

Wood Chips ◽

Standard Specification ◽

Stem Wood ◽

Nypa Fruticans ◽

Albizia Richardiana ◽

Nipa Palm

The study was conducted to find out the suitability of making particleboard using nipa palm (Nypa fruticans) stem wood and rajkoroi (Albizia richardiana) wood chips. Particleboards were fabricated at six different ratios of nipa palm stem and rajkoroi wood chips such as 100:0, 75:25, 50:50, 25:75, 10:90 and 0:100. Characteristics of particleboards such as modulus of rupture, internal bond strength, water absorption, thickness swelling and moisture content were measured. Results shows that particleboards made from 100% rajkoroi wood chips have the highest static bending properties and highest tensile strength properties of other particleboards but 100% nipa palm stem wood chips have the lowest static bending and lowest tensile strength properties of other particleboards. 10% nipa palm stem wood chips particleboard have the highest bending strength and tensile strength is better than 100% nipa palm stem wood chips and other mixing chips of particleboards. Mechanical, water resistance and dimensional stability properties were tested according to Indian standard specification. Tensile strength passed the British and German standard specification and nearest to Bureau of Indian Standard, bending strength was found nearest to Indian Standard but lower than German and British Standard specification. Strength property of rajkoroi wood chips particleboard is higher than nipa palm steam wood chips particleboard but dimensional stability is lower than nipa palm steam wood chips particleboard.

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Machine of testing the ceramic’s bending strength properties at high temperature and ultra-low speed

Frontiers of Mechanical Engineering in China ◽

10.1007/s11465-010-0094-x ◽

2010 ◽

Vol 5 (3) ◽

pp. 289-293

Author(s):

Jianhui Zhang ◽

Onuki Akiyoshi ◽

Fang Ye

Keyword(s):

High Temperature ◽

Bending Strength ◽

Strength Properties ◽

Low Speed

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A Comparison of the Loading Direction for Bending Strength with Different Wood Measurement Surfaces Using Near-Infrared Spectroscopy

Forests ◽

10.3390/f11060644 ◽

2020 ◽

Vol 11 (6) ◽

pp. 644 ◽

Cited By ~ 2

Author(s):

Yohei Kurata

Keyword(s):

Near Infrared ◽

Bending Strength ◽

Tensile Force ◽

Strength Properties ◽

Bending Test ◽

Tangential Section ◽

Compression Force ◽

Radial Section ◽

Loading Direction ◽

Light Acquisition

Wood is widely used throughout society for building resources and paper. To further expand wood’s use in the wood industry, we tested the bending strength properties of wood and certified its internal quality by using near-infrared spectroscopy (NIRS). In this study, the relationship between bending strength and loading direction was compared by changing the light acquisition point of wood surfaces to elucidate the anisotropy of the wood using NIRS. The two loading directions were defined by using a bending test as the radial section and the tangential section. Two light acquisition points with NIRS were also defined by a bending test as the loading position (the compression surface) and the opposite surface (the tensile surface), and a comparison was made between the prediction accuracy of the wood’s mechanical strength properties obtained via a bending test using two pieces of light acquisition data. The strength properties of the wood bending tests were the elastic modulus in bending (Eb), the bending strength (Fb) and density (DEN). Cryptomeria japonica was prepared and cut into a final size of 20 mm × 20 mm × 320 mm. Near-infrared (NIR) spectra were obtained from the compression force side and the tensile force side (calculating these averages), and a partial-least-squares regression (PLSR) was performed for the regression analysis. In the NIR measurement position, the best calibration results of the PLSR were the averaged data between the side undergoing the compression force and that undergoing the tensile force. Comparing the two loading directions, the result for the radial section was slightly superior to that of the tangential section. The radial section showed a good relationship between the spectra acquisition position and the arrangement of the wood’s structure. The estimation accuracy of bending strength properties differed depending on the location where the NIR spectra acquisition was performed.

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Influence of Site Conditions and Quality of Birch Wood on Its Properties and Utilization after Heat Treatment. Part I—Elastic and Strength Properties, Relationship to Water and Dimensional Stability

Forests ◽

10.3390/f10020189 ◽

2019 ◽

Vol 10 (2) ◽

pp. 189 ◽

Cited By ~ 4

Author(s):

Vlastimil Borůvka ◽

Roman Dudík ◽

Aleš Zeidler ◽

Tomáš Holeček

Keyword(s):

Heat Treatment ◽

Dimensional Stability ◽

Bending Strength ◽

Color Change ◽

Untreated Wood ◽

Strength Properties ◽

Treatment Temperature ◽

Impact Bending ◽

The Impact

This work deals with the quality of birch (Betula pendula) wood from different sites and the impact of heat treatment on it. Two degrees of heat treatment were used, 170 °C and 190 °C. The resulting property values were compared with reference to untreated wood samples. These values were wood density, compressive strength, modulus of elasticity (MOE), bending strength (MOR), impact bending strength (toughness), hardness, swelling, limit of hygroscopicity, moisture content and color change. It was supposed that an increase in heat-treatment temperature could reduce strength properties and, adversely, lead to better shape and dimensional stability, which was confirmed by experiments. It was also shown that the properties of the wood before treatment affected their condition after heat treatment, and that the characteristic values and variability of birch properties from 4 sites, 8 stems totally, were reflected in the properties of the heat-treated wood. Values of static MOR were the exception, where the quality of the input wood was less significant at a higher temperature, and this was even more significant in impact bending strength, where it manifested at a lower temperature degree. Impact bending strength also proved to be significantly negatively affected by heat treatment, about 48% at 170 °C, and up to 67% at 190 °C. On the contrary, the most positive results were the MOE and hardness increases at 170 °C by about 30% and about 21%, respectively, with a decrease in swelling at 190 °C by about 31%. On the basis of color change and other ascertained properties, there is a possibility that, after suitable heat treatment, birch could replace other woods (e.g., beech) for certain specific purposes, particularly in the furniture industry.

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