Mechanical Properties Of Medium Density Fiberboard Research Articles

Propriedades de painéis MDF fabricados com misturas de madeira de plantações de paricá e resíduos de madeira de espécies nativas da Amazônia

ABSTRACT Brazil stands out as one of the largest manufacturers of MDF (medium density fiberboard) in the world. The industries are concentrated in the south and southeast of the country and are primarily based on the use of Pinus and Eucalyptus wood, which are available in extensive planted areas. In the northern region, there is only one MDF industrial plant. Despite an abundance of potential raw materials in this region, there is a lack of studies on native species wood and their industrial waste utilization for MDF production. The present study aimed to evaluate the properties of MDF manufactured from a mixture of cultivated paricá (Schizolobium amazonicum) wood and wood waste from native Amazonian species. The study assessed the isolated effects of different proportions of the raw materials and panel thicknesses on MDF properties. Panels were produced, and samples were obtained for testing. Using standard procedures, the following properties were determined: density, water absorption, thickness swelling, internal bonding, static bending, and resistance to screw withdrawal. The results revealed a significant impact of the analyzed variables on some physical and mechanical properties of MDF. With the exception of internal bonding, all other properties of the evaluated MDF panels met the specified regulatory requirements for use in furniture manufacturing. It is concluded that mixtures of the assessed raw materials have great potential for MDF production in the furniture industry. However, adjustments in the production process are recommended to improve the internal bonding property.

Synthesis of graphene oxide (GO) and reduced graphene oxide (rGO) and their application as nano-fillers to improve the physical and mechanical properties of medium density fiberboard

Graphene is an advanced material in the carbon group and offers greater mechanical, electrical, structural, and optical properties. Graphene oxide (GO) and reduced graphene oxide (rGO) nanoparticles were synthesized and characterized and their special effects on enhancing the physio-mechanical characteristics of medium density fiberboard (MDF) were assessed. GO and rGO nanoparticles were added to urea formaldehyde (UF) resin at different weight percentages (1.0, 2.0, and 3.0 wt%) during the dosing process. To manufacture the MDF, nanofillers were created by sonication and combination with natural wood fibers. To observe the behavior of nanoparticles in the nanofillers, microstructure characterizations were conducted. The manufactured nano MDF samples underwent physical and mechanical testing. The incorporation of GO and rGO nanoparticles into UF resin led to significant improvements in the physical and mechanical properties of the MDF. The addition of GO and rGO nanoparticles at different weight percentages (1.0, 2.0, and 3.0 wt%) resulted in a range of improvements in thickness swelling (up to 53.3% and 35.2% for GO and rGO nanoparticles, respectively), water absorption (up to 23.3% and 63.15%, respectively), and thermal conductivity (up to 42.16% and 27.7%, respectively). Additionally, the internal bond and rupture modulus of the MDF was enhanced by 59.0% and 70.0%, respectively, for GO and 41.4% and 48.5% for rGO. The highest value of the modulus of rupture (MoR) was observed at a concentration of 3.0% of rGO nanoparticles (44.7 MPa). The findings also showed that thickness swelling (Ts) and water absorption (WA) exhibited directly proportional relationships for 3.0% GO and rGO. These results suggested that incorporating GO and rGO nanoparticles into UF resin can significantly improve the physical and mechanical properties of nano MDF.

Influences of hardening agent on some physical and mechanical properties of medium-density fiberboard

Effects of Ammonium chloride (NH4CI) as a hardening agent on thickness swelling (TS), water absorption (WA), screw holding resistance (SHR), Janka hardness, modulus of rupture (MOR), modulus of elasticity (MOE), and internal bonding (IB) properties of medium-density fiberboard (MDF) were evaluated. Target densities were 712 and 715 kg/m³ for hardener applied (0.75 kg/m³ solid as 10% solution (fiber dry wt.)) and unmodified factory made 18 mm thick MDF, respectively. A total of 400 samples were tested. Boards produced without hardener presented better mechanical properties except for SHR. Indeed, SHR was around 9.2% improved by hardener utilization. However, hardener utilization caused around 8.4%, 7.3%, 3.6%, and 1.3% decreases for MOE, MOR, IB, and Janka hardness, respectively. Surprisingly, soaking time caused opposite results for TS and WA. The TS and WA of the hardener utilized MDF decreased around 40.3% and 29.6% for short-term soaking (2h) but remarkable increases (around 62.4% and 20%, respectively) were observed for long-term (24h) soaking. Statistical analysis proved that there were statistically significant (P<0.05) differences between all the evaluated properties.

Physical and mechanical properties of binderless medium density fiberboard (MDF) from coconut fiber

Coconut fiber is a natural fiber extracted from coconut coir, a by-product of coconut based product. It is a potential material for fiberboard because it contains high cellulose and lignin which is similar to wood. Binderless medium density fiberboard (MDF) from coconut fiber was produced to reduce the consumption of wood and the emmission of synthetic adhesives such as urea formaldehyde using lignin as natural binder. The purpose of this research were to determine the physical and mechanical properties of MDF from coconut fiber based on SNI 01-4449-2006 and JIS A 5905:2003 and to investigate the effect of oxidation treatment, additional paraffin, and pressing time to the physical and mechanical properties of the fiberboard. The results showed that the fiberboards produced on this research had medium density of 0.44-0.56 g/cm3 which met the standard for MDF. Most of fiberboards from coconut fiber obtained in this study met the standard for physical properties such as density, moisture content, thickness swelling, and screw holding power. However, the mechanical properties such as modulus of elasticity, modulus of rupture, and internal bond of the fiberboards had not met the SNI 01-4449-2006 and JIS A 5905:2003 because of the lack of materials strength.

Application of High Conductive Nanoparticles to Enhance the Thermal and Mechanical Properties of Wood Composite

In the present work three different types of Nanofillers such as multiwalled carbon Nanotubes (CNTSs), aluminum oxide Nanoparticles and Nanosize activated charcoal were mixed with urea formaldehyde (UF) resin and used in the preparation of medium density fiberboard (MDF). The fillers has improved heat transfer during hot pressing and achieved proper curing due to enhanced thermos-physical properties of wood fibers. To improve the dispersion of Nanofillers into UF matrix, high speed mechanical stirring and ultrasonic treatments were used. The CNTSs were oxidized with nitric acid and the functional groups formed on its surface improved the dispersion and interaction with UF matrix. The mixing of CNTSs and Aluminum oxide with UF resin have reduced the curing time due to enhanced thermal conductivity of MDF matrix. The heat transfer during hot pressing of MDF improved significantly with the addition of CNTSs and Al2O3 Nanoparticle. The activated charcoal did not show much effect on heat transfer. The curing rate of UF resin improved with all the three Nanofillers, as the activation energy of UF curing decreases. The physical and mechanical properties of MDF have improved significantly with CNTSs and Al2O3 Nanoparticle. The activated charcoal has significantly decreased the formaldehyde emission of MDF.

Effects of Nano-Clay on Physical and Mechanical Properties of Medium-Density Fiberboards Made from Wood and Chicken-Feather Fibers and Two Types of Resins

Effects of Nano-Clay on Physical and Mechanical Properties of Medium-Density Fiberboards Made from Wood and Chicken-Feather Fibers and Two Types of Resins

The Effect of Post-Heat Treatment in MDF Panels

This study was to evaluate the effect of post-heat treatment on the physical and mechanical properties of MDF (Medium Density Fiberboard) panels. Commercial MDF panels were produced in Brazil using Pinus wood and urea-formaldehyde (UF) adhesive. The post-heat treatments were carried in a factorial 3 x 2 (three temperatures of heat treatment - 200, 225 and 250 °C, and two times - 5 and 10 minutes), and a control treatment (without heat treatment). Subsequently, the physical and mechanical tests were performed. From the results it can be concluded that: 1) The most effective thermal post-treatment for improving the dimensional stability of the MDF was applied at 225 ° C and 10 min; 2) All the thermally treated panels revealed a significant decrease in the modulus of rupture and modulus of elasticity (MOR and MOE) to bending when compared with the control panels without post-heat treatment.

ADSORPTION OF NANOWOLLASTONITE ON CELLULOSE SURFACE: EFFECTS ON PHYSICAL AND MECHANICAL PROPERTIES OF MEDIUM-DENSITY FIBERBOARD (MDF)

ABSTRACT Effects of nanowollastonite (NW) adsorption on cellulose surface were studied on physical and mechanical properties of medium-density fiberboard (MDF) panels; properties were then compared with those of MDF panels without NW-content. The size range of NW was 30-110 nm. The interaction between NW and cellulose was investigated using density functional theory (DFT). Physical and mechanical tests were carried out in accordance with the Iranian National Standard ISIRI 9044 PB Type P2 (compatible with ASTM D1037-99) specifications. Results of DFT simulations showed strong adsorption of NW on cellulose surface. Moreover, mechanical properties demonstrated significant improvement. The improvement was attributed to the strong adsorption of NW on cellulose surface predicted by DFT, adding to the strength and integrity between wood fibers in NW-MDF panels. It was concluded that NW would improve mechanical properties in MDF panels as a wood-composite material, as well as being effective in improving its biological and thermal conductivity.

Effects of wollastonite on the properties of medium-density fiberboard (MDF) made from wood fibers and camel-thorn

The effects of wollastonite fibers on the physical and mechanical properties of medium-density fiberboards composed of wood fibers with up to 10 % camel-thorn chips were studied. Approximately 30 % of the wollastonite fibers were less than 100 nm while the remainder were less than 1 μm. Wollastonite fibers significantly improved most of the physical and mechanical properties while addition of camel-thorn produced more variable effects on panel properties. Up to 10 % camel-thorn could be added to panels without negative effects. A combination of 10% camel-thorn and 5% wollastonite fibers produced panels with the best properties.

EFEITO DA ESPESSURA E DO VÃO NA DEFORMAÇÃO EM FLEXÃO DE PAINÉIS DE MADEIRA

RESUMO Este trabalho teve como objetivo avaliar a correlação entre as propriedades físicas e mecânicas de painéis de MDF (Medium Density Fiberboard ) e de MDP (Medium Density Particleboard ) utilizados na fabricação de móveis. Para análise dos painéis foram determinadas as propriedades físicas de densidade, e teor de umidade e as propriedades mecânicas em flexão estática (MOE e MOR). O experimento foi realizado com amostras de painéis, em três espessuras (15 mm, 18 mm e 25 mm) e três vãos considerando a relação L/h (vão dividido pela espessura) de 30, 35 e 40, totalizando nove tratamentos para cada tipo de painel, com três repetições. Essas amostras também foram submetidas a ensaios não destrutivos de flexão, com cargas equivalentes a 25 g.cm-² uniformemente distribuídas, em condições climatizadas (temperatura 20º C ±1 e umidade 65% ±1). A deformação final com a carga foi registrada após uma semana registrando-se ainda a deformação residual após a retirada da carga. Foi feita uma análise estatística dos resultados, onde se avaliou o efeito dos tratamentos relativos ao vão e a espessura. Uma análise das médias evidenciou diferenças significativas entre os valores obtidos em cada espessura. O vão demonstrou ter maior influência na deformação dos painéis do que a espessura. Entre as dimensões das amostras avaliadas a melhor relação encontrada foi L/h=30.

Effects of nano-wollastonite on physical and mechanical properties of medium-density fiberboard

Effects of nano-wollastonite (NW) on physical and mechanical properties of medium density fiberboard (MDF) were studied. NW was applied at 5, 10, 15, and 20 g/kg dry weight basis of wood fibers; the results were then compared with control specimens. Two application methods of NW were used: surface and internal applications. Density was kept constant at 0,67 g/cm3 for all treatments and tests were carried out in accordance with ASTM D-1037. Addition of NW contributed in improving the physical and mechanical properties of the panels, both when applied internally or as surface treatment. It was concluded that NW contents of 10% and 15% were the optimal levels for industrial purposes for internal and surface applications, respectively.

Numerical prediction of the stiffness and strength of medium density fiberboards

A numerical two scale method for the prediction of tensile and bending stiffness and strength of medium density fiberboards (MDF) is proposed with the aim to study the fiber orientation influence on mechanical properties of MDF. The method requires less experimental data to optimize MDF and to improve industrial manufacturing technology of MDF. A new method for computing orientation tensors of the compressed fiber network is proposed. First, the virtual microstructure is generated by simulations of a fiber lay-down and a subsequent compression to obtain the necessary density. The density profile, fiber length, thickness, and orientation are used for the microstructure generation, which are obtained from μCT images and image analysis tools. Then a new damage model for the wood fiber cell walls and joints is introduced. The microstructural problem is formulated as a Lippmann–Schwinger type equation in elasticity and solved by using Fast Fourier Transformation (FFT). The macroscopic three point bending test is simulated with hexahedral finite elements and analytical methods based on Euler–Bernoulli theory. The difference between bending strength and stiffness numerically obtained and corresponding experimentally measured values is less than 10%. This study lays a foundation for the optimal design of MDF fiber structures and the optimization of industrial manufacturing processes. The first results show an increase of up to 60% for bending stiffness in the case of strongly oriented fibers.

Effects of the Improvement in Thermal Conductivity Coefficient by Nano-Wollastonite on Physical and Mechanical Properties in Medium-Density Fiberboard (MDF)

The improving effect of an increase in the thermal conductivity caused by nano-wollastonite (NW) on the physical and mechanical properties of medium-density fiberboard (MDF) was studied. Nanowollastonite was applied at 2, 4, 6, and 8 g/kg, based on the dry weight of wood-chips, and compared with control specimens. The size range of wollastonite nanofibers was 30 to 110 nm. The results show that NW significantly (p < 0.05) increased thermal conductivity. The increased thermal conductivity resulted in a better curing of the resin; consequently, mechanical properties were improved significantly. Furthermore, the formation of bonds between wood fibers and wollastonite contributed to fortifying the MDF. It was concluded that a NW content of 2 g/kg did not significantly improve the overall properties and therefore cannot be recommended to industry. Because the properties of NW-6 and NW-8 were significantly similar, a NW-content of 6 g/kg can be recommended to industry to significantly (p < 0.05) improve the properties of MDF panels.

Physical and mechanical properties of medium density fiber board (MDF) fabricated from banana plant (Musa sapientum) stem and midrib

This study was under taken to identify the physical and mechanical properties of medium-density fiberboard (MDF) made from banana plant (Musa sapientum) and to evaluate the potential use of banana plant as a raw material of MDF. Two types of board were produced namely banana stem and mid rib of banana leaf MDF. Properties of both types of board compared with market MDF. Physical and mechanical properties were examined. The density of banana stem MDF, mid rib of banana leaf MDF and market MDF were respectively 0.78, 0.74 and 0.72 g/cm3. The MOR of banana stem MDF, mid rib of banana leaf MDF and market MDF was 50.91, 45.30 and 40.65 N/mm2, respectively. The MOE for banana stem MDF, mid rib of banana leaf MDF and market MDF was 3,939.25, 3,606.17 and 3,518.63 N/mm2, respectively. The physical and mechanical properties of the both types of board were better than market MDF. The both types of board follow the standard and it can be a good source of raw material for MDF industries.

Some physical and mechanical properties of medium-density fiberboard made from giant bamboo

The objective of this study was to evaluate the density, density profile, water swelling and absorption, modulus of elasticity and rupture from static bending, and tensile strength of experimental medium-density fiberboards manufactured using Dendrocalamus giganteus (Munro bamboo). The fiber production was carried out through the chemo-thermo-mechanical pulping process with four different conditions. The panels were made with 10% urea formaldehyde resin based on dry weight of the fibers, 2.5% of a catalyzer (ammonium sulfate) and 2% paraffin. The results indicate that treatments with the highest alkali (NaOH) percentage, time and splinter heating temperature improved the physical properties of the panels. The root-fiber interface was evaluated through scanning electron microscopy in fracture zones, which revealed fibers with thick, inflexible walls. The panels' mechanical properties were affected due to the fiber wall characteristics and interaction with resin. Giant bamboo fiber has potential for MDF production, but other studies should be carried out.

Properties of Medium-Density Fiberboards from Bagasse Digested with Different Retention Times

The present work deals with studying the influence of different steam digestion retention times on properties of finished medium-density fiberboard (MDF). It aims to operate the defibration process with the minimum deterioration of stored bagasse-fiber strength. In this respect the wet-stored bagasse (WSB) samples were studied, parallel to dry-stored bagasse (DSB) samples, at different digestion retention times. Regression equations of quadratic order were used to optimize the independent variables (retention time and storage period). The results obtained show that a relatively higher digestion time (353 s) reduced the hollocellulose and hemicellulose contents of WSB. In the case of DSB, the changes in chemical constituents as a function of retention time were not very significant because the mechanical properties of MDF (static bending, internal bond, and screw holding) produced from applying a higher digestion time do not fulfill the standard requirements of ANSI A208.2. However, digestion at a shorter retention time (253 s) is recommended for stored bagasse in order to produce a board that complies with the European standards on MDF. DSB fibers at all the examined retention times are recommended for comparison. The advantage of applying a shorter retention time is evident from preserving, to some extent, the chemical constituents of WSB fibers.

The ambient aging of wood fiber and its effect on mechanical properties of MDF panels

Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to study ambient-aged wood fibers and their effects on the mechanical properties of medium-density fiberboard (MDF). It was found that MDF made with ambient-aged fibers had poorer mechanical properties than MDF made with fresh fibers; this difference resulted from the alterations of surface characteristics of wood fibers after ambient aging, which led to poor wettability of the urea–formaldehyde (UF) resin applied to the aged wood fibers. After 6 months of ambient aging, the concentration of carbonyl groups in the fibers increased by 144%, while the pH value of wood fiber decreased from 5.2 to 4.7. SEM showed that much more UF resin agglomerated on the surface of ambient-aged fibers and the breakage of MDF made with aged fiber frequently occurred at the resin-fiber interfaces, indicated the poorer wettability of UF resin to fibers due to the decrease in surface energy after aging.

Influence of hydrothermal modification of fibers on some physical and mechanical properties of medium density fiberboard (MDF)

Any treatment of fibers can influence properties of medium density fibreboard (MDF). In this research, the effects of hydrothermal treatment on physical and mechanical properties of MDF were studied. Industrial fibers were hydrothermally treated in a stainless steel reactor at 120, 150 and 180 °C for 0, 30 and 90 min as holding time. Test boards were made based on 0.7 g/cm3 target density, with 10 mm thickness under a pressure of 30 bar and at a temperature of 170 °C and a press time of 10 min. The boards were tested for internal bonding (IB), moduli of elasticity (MOE) and rupture (MOR), thickness swelling and water absorption.