Medium Density Fiberboard Panels Research Articles

Study of the importance of non-uniform mass density in numerical simulations of fire spread over MDF panels in a corner configuration

The distribution of mass density through the thickness of Medium Density Fiberboard (MDF) panels is known to be non-uniform. A few studies have previously investigated the influence of this non-uniform through-thickness density distribution on the thermal behavior of MDF panels in small-scale tests. This study assesses the significance of this material property on flame spread simulations in a medium-scale set-up, namely that of Single Burning Item (SBI) corner fire tests. Simulations are performed using FireFOAM 2.2.x, considering both uniform and non-uniform MDF material density profiles, using model-effective material properties determined from bench-scale pyrolysis tests conducted in a Fire Propagation Apparatus (FPA). The heat transfer from the gas phase is modeled by means of empirical expressions with adjusted parameters. The simulations are assessed against the results of several SBI experiments with MDF panels and a test with Calcium Silicate (CS) panels. When the non-uniform nature of the through-thickness density is taken into account, the fire growth prediction in terms of the total Heat Release Rate (HRR) is considerably different (20% higher peak HRR), mainly due to the characteristic high peak mass loss rate at the initiation of pyrolysis of MDF material, resulting from the higher mass density near the surface of the panels. Furthermore, total heat fluxes on the panels, lateral flame spread, surface pyrolysis and through-thickness char formation visibly depend on the non-uniform distribution of mass density, particularly in regions further away from the corner where the influence of thermal attack from the burner is less dominant. A new diagnostic is proposed for determining the pyrolysis front location and spread on the surface of the charring panels.

Application of surface chemical functionalized cellulose nanocrystals to improve the performance of UF adhesives used in wood based composites - MDF type

The aim of this research was to investigate the effect of functionalized cellulose nanocrystals (CNC) on the performance of urea-formaldehyde (UF) adhesive for the production of medium density fiberboard (MDF). Surface modification of CNC was performed using 3-Aminopropyltriethoxysilane (APTES). Some physical and thermal properties of reinforced and neat UF as well as formaldehyde emission and some mechanical (modulus of rupture (MOR), modulus of elasticity (MOE) and internal bond strength (IB)) and physical properties (thickness swelling (TS) and water absorption (WA)) of the resulting MDF panels were determined. Based on the results, upon incorporation of modified CNC to the system, solid content, density, viscosity and free formaldehyde of UF adhesives decreased while gel time increased. Depending on addition of the modified CNC loading in the panels, the formaldehyde emission values varied from 11% to 17% lower than the panels made from neat UF. In comparison to the control samples, panels made with UF containing 2% modified CNC had 29.3% and 38.2% higher MOR and MOE respectively.

Facile one-step fabrication of highly hydrophobic medium density fiberboard (MDF) surfaces via spray coating

We proposed a simple and useful one-step spray coating method to protect MDF panels against physical and mechanical damages commonly presented in indoor real-life conditions. Highly hydrophobic surfaces were designed by TMCS (trimethylchlorosilane)-SiO2 nanoparticles deposition on MDF panels as a function of concentration of solution (0.1 and 0.3%) and number of cycles (10, 20 and 30 times). The formation of TMCS-SiO2 coating on MDF surface was investigated by scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), X-ray photoelectron spectroscopy (XPS), attenuated total reflectance with Fourier transform infrared spectroscopy (ATR-FTIR) and time-dependent apparent contact angle (WCA). Water drop impacting, dust impacting, and tape-peeling tests were conducted to simulate real-condition damages on MDF surfaces and to investigate the durability of highly hydrophobic coating. The coated MDF panels showed apparent water contact angle exceeding 140° with an interesting time-dependent stability and ability to roll-off, especially because the hydrophobicity of TMCS and hierarchical structure self-organized by spherical SiO2 nanoparticles. This rougher surface and presence of alkyl groups provide physical and mechanical durability of MDF panels even after water drop and dust impact tests, and tape-peeling up to five cycles. Therefore, this facile one-step MDF coating can be an effective, stable and mechanically durable alternative to protect MDF in undesirable real-life conditions.

Effects of recycled fiber content on the properties of medium density fiberboard

The large global production quantity of medium-density fiberboard (MDF) creates equal quantities of waste MDF, which consequently requires research on the recycling of MDF. This work was conducted to study the effect of recycled fiber (RF) content on the recycling properties of MDF. After pretreating waste MDF, a refiner and hammer were used to isolate refiner RFs (RRFs) and hammer mill RFs (HRFs) from two softwood species. This work also characterized the physical, chemical, and morphological features of RFs and virgin fibers (VFs). RRF and HRF contents of 0, 5, 10, 20, 30, 50, and 100% were used to fabricate recycled MDF (rMDF) panels. All RFs had shorter fiber lengths and higher fines contents than VFs had. The presence of N from urea–formaldehyde resins was confirmed by multiple analyses; more N was distributed in RFs than in VFs. The highest internal bonding (IB) strength of the rMDF occurred at 10% RF, regardless of isolation method and wood species; IB strength decreased afterward. The mechanical properties, including modulus of rupture, modulus of elasticity, and screw withdrawal resistance of rMDF, showed behaviors similar to the IB strength with increasing RF content. However, the thickness swelling, water absorption, and formaldehyde emission of rMDF samples decreased with increasing RF content. Statistical analysis indicates that the minimum of 10% RFs can be used to replace VFs without diminishing the properties of rMDF. The improved properties of rMDF were ascribed to the reinforcing effects of RFs covered with cured resins.

Analysis of the Cutting Parameters in Front Milling for Medium Density Fiberboard

Medium density fiberboard (MDF) is an industrial product manufactured from lignocellulosic fibers. It has homogeneity, dimensional stability, and mechanical strength compared with solid wood. Milling is a machining method widely used in the furniture industry; despite the relevance of the subject, there are few works dealing with the specific MDF milling process using computerized numerical control (CNC) machines. This study evaluated MDF milling in CNC machining centers by analyzing roughness. The MDF panels were front direction with the machined cut depth of 3 mm with six replicates, four cutting speeds of 804 m/min, 603 m/min, 402 m/min, and 201 m/min, and one forward speed of 4 m/min. The parameter of roughness average (Ra) was analyzed. The results showed that the surface roughness showed lower values for the cutting speeds of 603 m/min and 804 m/min, and cutting depths of 3 mm exhibited satisfactory results for the front surface. In conclusion, the parameters studied here significantly influence the finish, resulting in uneven surfaces that can reduce the quality of products.

Evaluation of palm fiber components an alternative biomass wastes for medium density fiberboard manufacturing

This work deals with assessing the date palm component wastes as alternative lignocellulosic material for production of Medium density fiberboards, in order to establish economic and balance between production/consumer ratio at different provinces rather than Upper Egypt. Palm leafs and palm frond was used as Medium density fiberboards precursors. Different urea formaldehyde levels (10-14%/fiber) and pressing pressure (25-35 bar) were applied in this evaluation. The acceptable interaction of palm fibers component with urea formaldehyde was optimized by characterizing its differential scanning calorimetry and thermogravimetric analysis, in comparison with commercial used sugarcane bagasse fibers. The promising Medium density fiberboards Panel is obtained from palm frond fibers and its mechanical and water resistance properties fulfill the ANSI standard for high grade Medium density fiberboards wood products, especially on applying urea formaldehyde level 12-14%, and pressing pressure, 35 bar. It is interesting to note that, applying higher pressing pressure together with 12% urea formaldehyde level provided palm frond-based Medium density fiberboards with static bending properties, higher than commercial bagasse-based Medium density fiberboards. The insignificant effect of pressing pressure was noticed on water swelling property and free-HCHO of Medium density fiberboards panels. Where, both type of fibers have the same water swelling property (reached ~ 10%), and free-HCHO (~ 27 mg/100g board).

Experimental study of corner fires—Part I: Inert panel tests

Corner fires are known to spread more intensely in comparison with single wall fires. In view of the challenges associated with prediction of such fire behavior, the fire growth in a corner configuration of Medium Density Fiberboard (MDF) panels is investigated to provide a set of experimental data, performing Single Burning Item (SBI) tests. First, though, test results with inert calcium silicate panels are discussed for three values of HRR (10, 30 and 55 kW), allowing to address the main physics involved. The experimental data for 30 kW, the default SBI HRR, is used for detailed discussion of the observations. The SBI testing methodology, materials, and set-up are described. The results of total Heat Release Rates (HRR) and Smoke Production Rates (SPR), as well as the panel temperatures and total heat fluxes at several characteristic locations are analyzed. Moreover, the puffing frequency of the corner fire is characterized thanks to Video Fire Analysis (VFA) of the experimental footage. Additionally, flame heights are discussed, including the concept of mirroring. A new correlation for mean flame height is introduced, using the hypotenuse of the triangle as characteristic length for entrainment of air into the fire plume, and expressing that the flame height increases proportional to the square root of the fire heat release rate. The 30 kW propane burner of the standard SBI test is shown to feature a mean flame height of nearly 0.9 m and a puffing frequency of 2 ± 0.3 Hz, and an average total heat flux exceeding 44 kW/m2 near the burner early on in the test. The completeness of the dataset is expected to be useful for testing and development of CFD codes for corner fire scenarios.

Experimental study of corner fires—Part II: Flame spread over MDF panels

Having explained the characteristics of a corner fire in the configuration of Single Burning Item (SBI) test in Part I [1], the results of three flame spread experiments conducted with Medium Density Fiberboard (MDF) panels are discussed. The fire growth, in terms of flame heights and spread, is examined from two different angles visually and through Video Fire Analysis (VFA) with a flame detection algorithm. Total Heat Release Rates (HRR) and Smoke Production Rates (SPR), as well as total heat fluxes at several characteristic locations, are presented. Moreover, temperature evolutions are discussed for multiple locations and through the thickness of the panels. Also the backside temperatures, important as boundary condition for numerical simulations, are reported. The corner fire tests with MDF panels yield an average peak HRR of 151 kW and an average total heat flux exceeding 60 kW/m2 close to the burner, with average flame heights surpassing 1.5 m in about 60 s.

Investigation of the effect on combustion resistance of ammonium polyphosphate and boric acid chemicals added to surface coating

Aim of study: The purpose of this study were determined the effect of ammonium polyphosphate (APP) and boric acid (BA) as surface coating materials on combustion resistance of MDF panels. Area of study: To ensure the retardation of combustion properties of wood based panels Material and Methods: Surface coating mixture consists of calcite, glue, fire retardant (FR) and water. The amount of glue (10%), APP and BA (1%, 3% and 5%) in the mixture was determined by the oven dry weight of calcite. Combustion tests of Medium Density Fiberboard (MDF) test specimens coated with 0.25 mm thickness of this mixture were carried out according to ASTM E 69 standards. Temperature, O 2 , CO and NO contents of samples were measured with Testo 340 M gas analyzer while weight loss was measured with digital scales. For each test, 20 measurements were recorded at intervals of 30 seconds. Main results: According to the obtained results, besides calcite coating, the increase of FR addition rate increased the resistance of combustion. It was found that the weight loss of the samples treated with APP 5% was the lowest (66,7%). Research highlights: The coating of the surfaces of wood-based boards and the addition of FR chemistry and mineral to this coating delays the burning properties

Effect of Panel Density and Resin Content on Properties of Medium Density Fiberboard

This study was conducted to evaluate the effect of panel density and resin content on properties of medium density fiberboard (MDF) to obtain some insights on MDF properties as a function of panel density and resin content. MDF panels with different panel densities such as 650, 700, 750 and 800 kg/m3 were manufactured by adjusting the amount of wood fibers in the mat forming. MDF panels were also fabricated by spraying 8, 10, 12, and 14% of urea-formaldehyde (UF) resins onto wood fibers in a drum-type mechanical blender to fabricate MDF panels with a target density of 650 kg/m3. As the panel density and resin content increased, the internal bonding (IB) strength of MDF panel consistently increased. Modulus of rupture (MOR), modulus of elasticity (MOE) and screw withdrawal resistance (SWR) had a similar trend to the IB strength. In physical properties, thickness swelling (TS) and water absorption (WA) decreased with an increase in both panel density and resin content. In addition, the formaldehyde emission (FE) which increased as the panel density and resin content became greater. In overall, the panel density of MDF had more significant effect than the resin content in all properties of MDF panels, indicating that it was better to adjust the panel density rather than the resin content for MDF manufacture.

Experimental and Theoretical Modal Analysis of Full-Sized Wood Composite Panels Supported on Four Nodes.

Key elastic properties of full-sized wood composite panels (WCPs) must be accurately determined not only for safety, but also serviceability demands. In this study, the modal parameters of full-sized WCPs supported on four nodes were analyzed for determining the modulus of elasticity (E) in both major and minor axes, as well as the in-plane shear modulus of panels by using a vibration testing method. The experimental modal analysis was conducted on three full-sized medium-density fiberboard (MDF) and three full-sized particleboard (PB) panels of three different thicknesses (12, 15, and 18 mm). The natural frequencies and mode shapes of the first nine modes of vibration were determined. Results from experimental modal testing were compared with the results of a theoretical modal analysis. A sensitivity analysis was performed to identify the sensitive modes for calculating E (major axis: Ex and minor axis: Ey) and the in-plane shear modulus (Gxy) of the panels. Mode shapes of the MDF and PB panels obtained from modal testing are in a good agreement with those from theoretical modal analyses. A strong linear relationship exists between the measured natural frequencies and the calculated frequencies. The frequencies of modes (2, 0), (0, 2), and (2, 1) under the four-node support condition were determined as the characteristic frequencies for calculation of Ex, Ey, and Gxy of full-sized WCPs. The results of this study indicate that the four-node support can be used in free vibration test to determine the elastic properties of full-sized WCPs.

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.

Measurement of Molecular Weights of Melamine-Urea-Formaldehyde Resins and Their Influences to Properties of Medium Density Fiberboards

This study attempted to measure molecular weight (MW) of melamine-urea-formaldehyde (MUF) resins prepared by two different synthesis methods: the one-step MUF resins were synthesized in one batch procedure, while the two-step MUF resins were prepared by a physical mixing of urea-formaldehyde (UF) resin with melamine-formaldehyde (MF) resin that had been synthesized in a separate procedure. The properties of medium density fiberboard (MDF) panels bonded with two types of MUF resins were also investigated. MWs of these MUF resins were measured using gel permeation chromatography (GPC). In addition, this study measured the MWs of one-step MUF resin during its synthesis procedure. The performance of two types of MUF resins was evaluated by determining properties of MDF panels prepared in laboratory. As the synthesis procedure progressed, both number average MW (Mn) and weight average MW (Mw) of one-step MUF resin gradually increased, while the polydispersity index (PDI) decreased. And low MW species of the resin predominantly decreased as the synthesis step progressed. The one-step MUF resin showed greater Mn and Mw than those of the two-step ones even though the PDI values of both resins were very similar each other. As expected, the one-step MUF resin resulted in better properties of MDF panels than those of two-step resins. In particular, the one-step MUF resin provided better internal bond (IB) strength and thickness swelling (TS) with MDF panels than those of two-step ones, indicating better water resistance of the one-step resin. These results suggest that the preparation method of MUF resins have a great impact on the MW and final panel properties.

Optimization of processing parameters of medium density fiberboard using response surface methodology for multiwalled carbon nanotubes as a nanofiller

In the present work, medium density fiberboard (MDF) panels were produced using multiwalled carbon nanotubes (MWCNT) reinforced urea formaldehyde resin. Response surface methodology was employed to optimize the relationship between the three variables, viz. pressing time, percentage of UF resin and percentage of MWCNT, used in the fabrication of MDF, and the influence of variables on the internal bonding (IB) and modulus of rupture (MOR) was studied. The optimum conditions based on the IB strength were determined as 8.18 % of UF resin, pressing time of 232 s, and MWCNT of 3.5 %. Similarly, the optimized conditions for MOR are also reported in this paper.

Life cycle assessment of medium-density fiberboard (MDF) manufacturing process in Brazil

Brazil is one of the largest producers of medium-density fibreboard (MDF) in the world, and also the MDF has the highest domestic consumption and production rate in the country. MDF applications are highlighted into residential and commercial furniture design and also a wide participation in the building sector. This study aimed to propose ways of improving the environmental cradle-to-gate life-cycle of one cubic meter MDF panel by means of a life-cycle assessment (LCA) study. Complying with requirements of ISO 14040 and 14,044 standards, different MDF manufacturing scenarios were modelled using Umberto® v.5.6 software and the Ecoinvent v.2.2 life-cycle inventory (LCI) database for the Brazilian context. Environmental and human health impacts were assessed by using the CML (2001) and USEtox (2008) methods. The evaluated impact categories were: acidification, global warming, ozone layer depletion, abiotic resource depletion, photochemical formation of tropospheric ozone, ecotoxicity, eutrophication and human toxicity. Results identified the following hotspots: gas consumption at the thermal plant, urea-formaldehyde resin, power consumption, wood chip consumption and wood chip transportation to the plant. The improvement scenario proposals comprised the following actions: eliminate natural gas consumption at the thermal plant, reduce electrical power consumption, reduce or replace urea-formaldehyde resin consumption, reduce wood consumption and minimize the distance to wood chip suppliers. The proposed actions were analysed to verify the influence of each action on the set of impact categories. Among the results, it can be noted that a joint action of the proposed improvements can result in a total reduction of up to 38.5% of impacts to OD, 34.4% to AD, 31.2% to ET, and 30.4% to HT. Finally, MDF was compared with particleboard production in Brazil, and additional opportunities to improve the MDF environmental profile were identified.

Adhesion performance and film formation of acrylic emulsion coating on medium density fiberboard treated with Ar plasma

This work investigates the adhesion properties of medium density fiberboard (MDF) panel surfaces treated by an argon plasma at two power levels (50 and 150W) and four glow discharge times (10, 40, 60 and 120s) and then coated with an acrylic emulsion. Wettability parameters and film formation kinetics were investigated by water apparent contact angle and diffusing wave spectroscopy, respectively. Pull-off strength was used to determine coating/wood adhesion. The aging effect of 300-days in storage at ambient conditions was examined by apparent contact angle measurements. The wettability of the MDF surface was enhanced significantly - especially at the 150W power level – that improves coating/wood adhesion. A film formation process occurred in shorter time for plasma treated samples due to the faster motion of particles. MDF panels partially recovered their natural hydrophobicity in the first ten days of storage. Nevertheless, higher levels of power and time of glow discharge were able to slow down the aging effects.

Properties of Honeycomb Paperboards Faced with Heat-Treated Thin Medium-Density Fiberboards

In this study, 4-mm-thick medium-density fiberboard (MDF) panels were heat-treated at 140 °C for 30 or 60 min and at 180 °C for 30 or 60 min. Then, 10-mm-thick lightweight honeycomb paperboards made from kraft paper (130 g/m2, cell diameter of honeycomb, 14 mm; compression strength, 0.21 N/mm2) were faced with the untreated and heat-treated MDF panels (thickness: 4 mm) using a two-component polyurethane adhesive. The density, thickness swelling, water absorption, and flexural properties of the paperboards faced with the untreated and heat-treated MDF panels were investigated. The lowest flexural strength (3.76 N/mm2) and flexural modulus (392 N/mm2) values were found in the specimens faced with the MDFs treated at 180 °C for 60 min, while the highest flexural strength (4.20 N/mm2) and flexural modulus (457 N/mm2) values were found in the specimens faced with the untreated MDFs. The loss in strength was primarily attributable to the degradation of hemicelluloses, which are less stable to heat than cellulose and lignin. The thickness swelling and water absorption of the honeycomb paperboards faced with the heat-treated MDF panels significantly (p < 0.01) decreased with the increase in heat-treatment temperature and duration.

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.

Characteristics of Medium Density Fiberboards for Furniture Production and Interior Application

BACKGROUND: The paper analyzes the properties of medium density fiberboards (MDF) intended for furniture production and interior application. Because MDF panels are one of the mostly used wood-based panels in furniture production sector in the Republic of Macedonia it is important to know and understand their basic physical and mechanical properties. AIM: For better understanding of MDF panels and their proper end use by the furniture constructors and designers, physical and mechanical properties of MDF panels present in the market are tested.MATERIALS AND METHODS: Commercially produced MDF panels taken from one company from wood-based panel market were tested. Evaluation of the quality of the panels was made on the basis of the obtained results for the physical and mechanical properties of the panels. Properties of MDF were tested according to the national MKS standards and European norms.RESULTS: Tested MDF panels present on our market are characterized by good physical and mechanical properties that meet the requirements of the standards for MDF for use in dry conditions including furniture production and interior applications.CONCLUSIONS: It is recommended to avoid application of these MDF panels in high humidity conditions for a longer exploitation period. For this kind of applications, such as bathroom areas, the furniture constructors and interior designers should consider use of MDF.H type of panel for application in high humidity conditions, which will provide good dimensional stability of the products during whole exploitation period.

Experimental Investigation and Analysis on Thrust Force in Drilling of Wood Composite Medium Density Fiberboard Panels

Wood-based composites are finding increased applications over solid wood because of their important properties such as strength, aesthetic appearance, etc. to reuse the waste wood from other process and also because of the scarcity of solid wood. Medium density fiberboard (MDF) is a wood-based composite widely used in domestic, furniture manufacturing industries, construction, interior and exterior works. Machining process like drilling develops cutting force plays an important role in the quality of the final product. The cutting force developed can be controlled by the proper selection of input process parameters. The objective of this study is to analyze the influence of cutting conditions on the thrust force developed in drilling to predict the optimal cutting conditions of drilling parameters such as spindle speed, feed rate, and point angle. Taguchi design of experiments is used to perform the drilling tests. Response surface methodology (RSM) is used to develop the model to predict the influence of cutting parameters on thrust force and the adequacy of the developed model is checked with analysis of variance (ANOVA). It is revealed that the high spindle speed with low feed rate combination minimizes the thrust force in drilling of MDF panels.