Medium Density Fiberboard Board Research Articles

Thermally Active Medium-Density Fiberboard (MDF) with the Addition of Phase Change Materials for Furniture and Interior Design.

No matter where we reside, the issue of greenhouse gas emissions impacts us all. Their influence has a disastrous effect on the earth's climate, producing global warming and many other irreversible environmental impacts, even though it is occasionally invisible to the independent eye. Phase change materials (PCMs) can store and release heat when it is abundant during the day (e.g., from solar radiation), for use at night, or on chilly days when buildings need to be heated. As a consequence, buildings use less energy to heat and cool, which lowers greenhouse gas emissions. Consequently, research on thermally active medium-density fiberboard (MDF) with PCMs is presented in this work. MDF is useful for interior design and furniture manufacturing. The boards were created using pine (Pinus sylvestris L.) and spruce (Picea abies L.) fibers, urea-formaldehyde resin, and PCM powder, with a phase transition temperature of 22 °C, a density of 785 kg m-3, a latent heat capacity of 160 kJ kg-1, a volumetric heat capacity of 126 MJ m-3, a specific heat capacity of 2.2 kJ kgK-1, a thermal conductivity of 0.18 W mK-1, and a maximum operating temperature of 200 °C. Before resination, the wood fibers were divided into two outer layers (16%) and an interior layer (68% by weight). Throughout the resination process, the PCM particles were solely integrated into the inner layer fibers. The mats were created by hand. A hydraulic press (AKE, Mariannelund, Sweden) was used to press the boards, and its operating parameters were 180 °C, 20 s/mm of nominal thickness, and 2.5 MPa for the maximum unit pressing pressure. Five variants of MDF with a PCM additive were developed: 0%, 5%, 10%, 30%, and 50%. According to the study, scores at the MOR, MOE, IB, and screw withdrawal resistance (SWR) tests decreased when PCM content was added, for example, MOE from 3176 to 1057 N mm-2, MOR from 41.2 to 11.5 N mm-2, and IB from 0.78 to 0.27 N mm-2. However, the results of the thickness swelling and water absorption tests indicate that the PCM particles do not exhibit a substantial capacity to absorb water, retaining the dimensional stability of the MDF boards. The thickness swelling positively decreased with the PCM content increase from 15.1 to 7.38% after 24 h of soaking. The panel's thermal characteristics improved with the increasing PCM concentration, according to the data. The density profiles of all the variations under consideration had a somewhat U-shaped appearance; however, the version with a 50% PCM content had a flatter form and no obvious layer compaction on the panel surface. Therefore, certain mechanical and physical characteristics of the manufactured panels can be enhanced by a well-chosen PCM addition.

Determination of the properties of medium-density fiberboards produced using urea-formaldehyde resins modified with boron compounds

Effects of adding different boron compounds to the urea-formaldehyde resin were evaluated relative to the physical, mechanical, and other properties of medium-density fiberboard (MDF). While the chemical addition of boric acid to the urea-formaldehyde resin increased the modulus of rupture and modulus of elasticity values of MDF boards, the physical and chemical additions of other boron compounds decreased those values. While there were no significant decreases in internal bond values, the chemical addition of boric acid and borax decahydrate to urea-formaldehyde resin increased the internal bond values of MDF boards. It was observed that in both types of addition, borax pentahydrate reduced the formaldehyde emission values of MDF boards the most and also reduced the burnt area by up to 30%. When the type of addition of boron compounds to urea-formaldehyde was compared, the addition of boron compounds at the resin formation stage showed better results in the properties of MDF boards than physical addition.

Combining Artificial Neural Network and Response Surface Methodology to Optimize the Drilling Operating Parameters of MDF Panels

Most of the parts of furniture made of medium density fiberboards (MDF) require at least one hole to be assembled. The drilling technological parameters influence the quality of holes. Factors such as tip angle of the drill bit, feed rate, type and diameter of the drill bit, and spindle rotational speed could affect the drilling process. Therefore, the right choosing of drilling parameters is a mandatory condition to improve the drilling efficiency that is expressed through tool durability, cost, and quality of the drilling. Thus, in this work, we are proposed an approach that consists in combining two modelling techniques, which were successfully applied in various fields, namely artificial neural network (ANN) and response surface methodology (RSM), to analyze and optimize the drilling process of MDF boards. Four artificial neural network models with a reasonable accuracy were developed to predict the analyzed responses, namely delamination factor at inlet, delamination factor at outlet, thrust force, and drilling torque. These models were used to complete the experimental design that was requested by the RSM. The optimum values of the selected factors and their influence on the drilling process of the MDF boards were revealed. A part of optimum combinations among analyzed factors could be used both during the drilling of the MDF boards and prelaminated wood particleboards.

Modified graphene as potential additive for urea formaldehyde (UF) resin in medium density fiberboard (MDF) manufacturing

In this study, graphene oxide (GO) and ethylenediamine-functionalized graphene oxide (EDA-GO) materials were used as a multifunction additive in a UF resin to test the relevant effects on the release of formaldehyde from medium density fiberboard (MDF). The GO was synthesized from graphite using the modified hummers method. Then, the as-synthesized GO was functionalized with ethylenediamine (EDA). The as-synthesized and modified nanomaterials were characterized by XRD, Raman Spectroscopy, AFM, and SEM-EDS techniques. These tests confirmed that the nanomaterials were of the required quality, and they were added to the resin to make the relevant panels. After making the boards, they were tested to determine their physical and mechanical properties, as well as formaldehyde emission based on relevant standards. Modulus of elasticity and formaldehyde emission reduction of the EDA-GO3-treated MDF panel were with the highest values. On the contrary, the higher performance of GO than that of EDA-GO was observed in a thermal property (t100°C). Microstructure and polar increase in the graphite planes network, due to oxidation, may be considered for its GO effects. Amino-functionalization of graphene oxide planes is suggested as the cause of the minimum formaldehyde emission and the maximum modulus of elasticity in the EDA-GO-incorporated MDF board since resin reaction sites with formaldehyde were enhanced by increasing the amine group content.

Utilization of activated carbon as an additive for urea-formaldehyde resin in medium density fiberboard (MDF) manufacturing

In this study, the MDF sanding dust was examined as a precursor for synthesizing activated carbon (AC). For this purpose, MDF sanding dust was impregnated with KOH at two different weight ratios 1:0.50 and 1:1 (sanding dust/KOH). The process was done in one step at a temperature of 750 °C and a heating rate of 8 °C/min. The synthesized ACs at different content were added into urea-formaldehyde (UF) resin for medium density fiberboard (MDF) production. The laboratory MDF boards were produced using a hot press at a temperature of 190 °C and pressure of 40 MPa. The ACs content in UF resin was set at 0.25%, 0.50% and 1% based on the dry weight of the resin. The ACs were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The BET equation was used to determine the specific surface area of the AC samples. Water absorption, thickness swelling, internal bonding, flexural modulus and strength, and the formaldehyde emission from MDF boards were determined. The curing behavior of UF resins were evaluated using Differential Scanning Calorimetry (DSC). The results revealed that surface area and micropore volume of ACs increase with increasing KOH ratio; and the ACs exhibited three-dimensional porous network structures. The DSC results also showed that the ACs significantly increase the reaction enthalpy of UF resins. The addition of AC as an additive to UF resin significantly reduces formaldehyde release from MDF boards and improves their physical and mechanical properties.

Experimental Investigation of Vertical Density Profile of Medium Density Fiberboard in Hot Press

This research investigates the performance of medium density fiberboard (MDF) with respect to hot press parameters. The performance of the board, type of glue, and production efficiency determine the optimum temperature and pressure for hot pressing. The actual temperature of the hot press inside the MDF board determines the properties of the final product. Hence, the optimal hot press parameters for the desired product are experimentally obtained. Moreover, MDF is experimentally investigated in terms of its vertical density profile, bending, and internal bonding under the various input parameters of temperature, pressure, cycle time, and moisture content during the manufacturing process. The experimental study is carried out by varying the temperature, pressure, cycle time, and moisture content in the ranges of 200–220 °C, 145–155 bar, 260–275 s, and 8–10%, respectively. Consequently, the optimum input parameters of a hot-pressing temperature of 220 °C, pressure of 155 bar, cycle time of 256 s, and moisture content of 8% are identified for the required internal bonding (0.64 N/mm2), bending (32 N/mm2), and increase in both the core and peak density of the vertical density profile as per the ASTM standard.

Effect of calcite addition on technical properties and reduction of formaldehyde emissions of medium density fiberboard

Physical, mechanical, and formaldehyde emission properties were studied for medium density fiberboard (MDF) produced with oak (75%) and pine (25%) fibers that had been mechanically refined in the presence of calcite particles. The calcite slurry was prepared at two levels of solids, 1.5% and 3% (10 and 20 kg·m-³). Chips were cooked for 4 min at 185 °C, under 8 bar vapor pressure in an Andritz defibrillator. 1.8% liquid paraffin, 0.72% ammonium sulphate solution, and 11% urea-formaldehyde were added by percentage based on oven-dried wood fibers in the blowline at the exit of the defibrator. The fibers were dried to 11% moisture content. MDF boards (2100 mm × 2800 mm × 18 mm) were created using a continuous hot-press process. The addition of calcite in the course of MDF production resulted in improved physical properties, such as thickness swelling (ThS 24 hours) and water absorption (WA 24 hours). MDF boards prepared with calcite exhibited higher internal bond (IB), modulus of rupture (MOR), and modulus of elasticity (MOE). Resistance to axial withdrawal of screw also was increased by addition of 3% calcite. In addition, the lowest levels of formaldehyde emission were observed for MDF prepared with calcite at the 3% level.

Treatment of dose nonuniformity inside star apples irradiated by 10 MeV electron beam

A treatment of dose nonuniformity inside Lo Ren and purple star apples irradiated by 10 MeV electron beam accelerator has been proposed by using medium density fiberboards (MDF). The dose uniformity ratios (DURs) inside the Lo Ren and purple star apples were estimated as 2.47–2.48 and 2.18–2.22, respectively. To reduce the DURs, the arrangement and the thickness of the MDF boards were determined by Monte Carlo simulations. Measurements of the absorbed doses have been conducted to compare with the simulations. The DURs were reduced to 1.36–1.39 and 1.44–1.46 for the Lo Ren and purple star apples, respectively.

Effect of Panel Moisture Content on Internal Bond Strength and Thickness Swelling of Medium Density Fiberboard.

Wood-based products usually have serious limitations concerning contact with water, both because wood is a hygroscopic material and because the commonly used binder has low moisture resistance. This paper studies the effect of panel moisture content (MC) on the physico-mechanical properties of medium density fiberboards (MDF). Several commercial MDF boards produced in Europe were stored at room temperature and relative humidity (RH) for 9 weeks (approx. range 15–20 °C and 50–85% RH). Every week, a strip of each MDF board was cut out, divided into 5 × 5 cm test pieces and its internal bond strength (IB) was measured. A strong influence of MDF moisture content on internal bond strength was observed and therefore IB test pieces were stored in a climatic chamber (either at 20 °C, 55% RH and at 20 °C, 70% RH). A decreasing linear relation was established between IB and MC. It was found that this effect is reversible: after drying, internal bond strength rises again (following a slight hysteresis). This work reinforces the importance of conditioned storage before board properties analysis, as described in European Standard EN 319.

Mechanical and formaldehyde-related properties of medium density fiberboard with zeolite additive

Zeolite was investigated as a potential component in the production of medium-density fiberboard (MDF). A mixture of beech (40%), oak (30%), and pine (30%) wood chips was used for fiber production. Chips were cooked for 4 min in an Asplund defibrator with a vapor pressure of 8 bar, and a temperature of 180 °C. Chemicals were added on fibers in the blow line. The resins were added at 11 wt% based on oven-dried wood fibers. Ammonium sulphate was added at 0.72 wt% based on resins. Paraffin wax was added as 1.8 wt% based on resin. Zeolite was prepared in a separate tank for its use instead of lignocellulosic fibers in the production of 1 m³ MDF. The fibers were dried to 12% moisture. A temperature of approximately 190 °C and a pressure of approximately 32 kg.m-² were applied to the mixture for 280 s to make MDF panels (500 x 490 x 14 mm). Mechanical properties of MDF boards were significantly increased for bending (MOE) and elastic modulus (MOR), but a little negatively affected on internal bond (IB), physical properties were negatively increased thickness swelling (ThS) and water absorption (WA). Consequently, increasing zeolite minerals in MDF boards showed best results of formaldehyde emission properties of MDF.

Practical properties and formaldehyde emission of medium density fiberboards (MDFs) recycled by electrical method

In this study, the performance of the electrical method in MDF wastes recycling was determined. For investigating the practical aspect of the electrical method, the hydrothermal method as a known recycling method was studied too. The recycling process by electrical method conducted for two different time durations (2 and 4 min) at a temperature of 100 °C and recycling using the hydrothermal method was done at a temperature of 105 °C for 150 min under 4 bar pressure with subsequent refining step. Recycled fibers were analyzed by determination of the chemical composition of fibers and fiber classification. After that, laboratory MDF boards with dimensions of 35 × 35 × 12 mm3 and density of 0.7 g/cm3 were manufactured. Practical properties of MDF boards including thickness swelling, modulus of rupture, modulus of elasticity and internal bonding were studied according to EN standard. Formaldehyde emission of boards was measured using the desiccator method. The results showed that some changes in the chemical composition of recycled fibers had occurred as compared to the original fibers, especially for the hydrothermal method where lignin content was significantly reduced. Fiber classification test showed significant reduction in the length of the fibers recycled by hydrothermal method as compared to other fibers. Investigations of the quality of manufactured MDF boards showed that the electrical method performed better in comparison with the hydrothermal method. The results of this study confirmed the positive effect of recycled fibers on reducing the formaldehyde emission from MDF boards which can be considered as an excellent benefit for the recycling process due to the importance of environmental and human health issues.

The effects of some flame retardant chemicals used in surface coating on the burning properties of MDF (Medium density fiberboard)

In this study, the surfaces of MDF were coated with a mixture of calcite, fire retardant (FR) and glue. Then the properties of MDF boards combustion resistance were investigated. Borax and muscovite, known as flame retardants, were added to the mixture at 1%, 3% and 5% relative to the oven dry weight of calcite. The burning tests of the samples were carried out according to ASTM E 69 standard so that the combustion characteristics could be determined. The weight loss, temperature, O2, CO and NO gas emissions quantities of the test samples were measured. The measurements were recorded every 30 seconds. Borax had the most positive effect on weight loss (74.5%) and O2 amount (20.5%), while muscovite 5% chemistry had a greater effect on temperature (289 oC) and NO amount (342 ppm). Borax and muscovite used in surface coating have been positively influenced on burning performance depending on addition rate.

EVALUATION OF BIOGAS CALORIFIC POTENTIAL FOR USE IN MEDICINAL PLANT DRYERS

The objective of this study was to evaluate the use of thermal energy from the burning of biogas for heating air and its potential use in a drying chamber. A prototype was built to evaluate the air heating in the heating system and in a drying chamber. The biogas composition used was 60.00% methane (CH 4 ). Treatments were composed by pressure difference applied to biogas, in which: T0 (no heating), T1 (pressure 130.00 to 200.00 kPa), T2 (pressure 200.00 to 270.00 kPar) and T3 (pressure 270.00 to 340.00 kPar) in six replications. A gas water heater (LPG) was adapted for use with biogas. The drying chamber was built with MDF (Medium Density Fiberboard) boards and thermally insulated with a total usable volume of 0.544 m³ and air velocity of 1.58 m.s -1 . The burning of biogas generated 36,10MJ h -1 , 68.95MJ h -1 and 76.03MJ h -1 for treatments T1, T2 and T3 respectively, meeting the need for heating in the drying chamber operating at temperatures of 43.05 oC (T1), 52.56 oC (T2) and 53.56 oC (T3). The heating system proposed has proved to be effective for drying different species of medicinal plants, since it meets the temperature range specified in the literature.

Evaluation of UF resin content in MDF boards after hot-pressing by Kjeldahl method

Understanding resin behavior during hot pressing of medium density fiberboard (MDF) is important to optimize panel properties. Before gelation, the mobility of the resin can affect its distribution and penetration on the wood cells during pressing. The resin in MDF boards occurs as coverage on the fibers surface and also penetrates within the fibers. In this paper, the effect of final resin content and physical–mechanical properties of MDF panels was measured under different conditions of press time, temperature and initial resin content. The measurements were performed by the Kjeldahl method. Results showed that a higher amount of initial resin led to a higher resin content in MDF boards. At the same amount of initial resin, a higher final resin content was obtained by increasing the pressing temperature. Furthermore, the final resin content affects the board properties such as internal bond strength and modulus of rupture. The results showed good correlation between mechanical properties and thickness swelling.

Evaluation of Termite Resistance of Medium Density Fiberboard (MDF) Manufacture from Agricultural Fiber Bonded with Citric Acid

Nowadays, the use of agricultural fibers for panel composite materials attracts great intention. Further, it is desirable to develop of natural adhesive derived from non fossil resources to be safe adhesive without using harmful chemical substances. In this study, citric acid application as natural adhesive was investigated for medium density fiberboard (MDF) manufacture from pineapple leaf fiber. The ratio of citric acid and sucrose and adhesive content was 25–75 and 20 wt%, respectively. Two different types of board consisting of three layers with target density of 0.8 gr/cm3 were prepared. The board was hot pressed at 200°C and 4.5MPa for 10min.Additionalboards with same structure were prepared using citric acid only. The biological properties of the boards such as their resistance against subterranean termite attack have been examined. The results indicate that generally, there was a significant effect of impregnation with mixture of citric acid and sucrose and citric acid only on the susceptibility of the MDF board specimens. With regards to the percentage of specimen mass losses, fiber orientation had no significant effect on the termite resistance against Coptotermes formosanus Shiraki. Utilization of natural adhesive, citric acid was promising to be used for MDF manufacturing. Our findings show that the total adhesive content of 20% of the type a board could be used for agricultural fiber product applications to protect structures from degradation by termites.

Effects of Nano-Wollastonite on Thermal Conductivity Coefficient of Medium-Density Fiberboard

Effects of Nano-Wollastonite on Thermal Conductivity Coefficient of Medium-Density Fiberboard Effect of wollastonite nanofibers on the improvement of thermal conductivity coefficient of medium-density fiberboard (MDF) was studied here to find a possible solution to decrease hot-press time as a bottle-neck during composite production. Nanowollastonite (NW) was applied at 10%, based on the dry weight of wood fibers. Density of the control MDF boards was 0.66 g/cm3. Thermal conductivity coefficient was measured using an apparatus based on Fourier’s Law for heat conduction. Results indicated that thermal conductivity was increased by 11.5% in NW-treated MDF boards in comparison to the control boards; thermal conductivity of control MDF was 0.099, whereas that of the NW-treated MDF boards was 0.110 (w/mk). It may then be concluded that higher thermal conductivity of wollastonite nanofibers, spread all over the MDF-matrix, resulted in the increased thermal conductivity coefficient of NW-treated boards. This increased thermal conductivity contributed to better resin cure in the core section of the MDF mat, resulting in improved physical and mechanical properties reported in prior studies.

Investigation on lateral resistance of joints made with drywall and sheet metal screws in bagasse particleboard and comparison with that of commercial MDF

In this research, effects of screw diameter, screw type, panel type, and end distance on lateral resistance of the joints made with drywall and sheet metal screws were studied in bagasse particleboard and the results were compared to those obtained from commercial medium density fiberboard (MDF). The accuracy of EYM in prediction of lateral resistance was then investigated. The drywall screws comprised of size 8 with coarse thread and size 10 with fine thread; the sheet metal screws comprised of size 8 and 10 with normal thread. Results indicated that lateral resistance increased with the increase in the diameter of both screw types, although not statistically significant. The lateral resistance obtained from MDF specimens was 20% more than that of bagasse specimens. Increase in the end distance also resulted in an increase in the lateral resistance. In all cases, sheet metal screws showed higher lateral resistance in comparison to those obtained from drywall screws. It can be concluded that Mode IIIs is more accurate than Mode Is in the prediction of lateral resistance in two-member screwed joints (single shear plane) for both MDF and bagasse boards.

Effect of Resination Technique on Mechanical Properties of Medium Density Fiberboard

Effects of different resination techniques relative to the mechanical properties of commercially produced thick medium density fiberboard (MDF) were investigated. The amount of urea-formaldehyde resin (11 wt%) applied to the wood fibers was gradually decreased in the blowline (11, 10.5, 10, and 9.5 wt%), while it was gradually increased in the short-retention blender (0, 0.5, 1, and 1.5. wt%). The internal bond strength of the MDF boards considerably improved as the amount of the resin applied to the fibers in the short-retention blender was increased to 1.5 wt%. In particular, the increase in the IB strength was most pronounced as the resin content increased from 1 to 1.5%. The edge and face screw withdrawal resistances increased by 7.7 and 7.9% as the amount of the resin applied to the fibers in the blender was increased. Similar values were also observed for the flexural properties. Overall, the total resin content in the production of thick MDF can be decreased as blender resination, a means of post-dryer resin addition, is incorporated into the blowline resination technique.

The performance of corn and cotton stalks for medium density fiberboard production

Severe shortage of suitable wood for Medium Density Fiberboard (MDF) production makes it necessary to consider using uncommon and non-conventional raw materials such as agricultural residues. In order to demonstrate the suitability and the potential of two agricultural residues (cotton and corn stalks), laboratory MDF boards were produced. Three press temperatures (170, 180 and 190 ºC) were used. Test samples were prepared from the boards after conditioning at 65% RH and 21 ºC, and all tests were performed according to relevant EN standard methods. The results indicated that the MOR and MOE of boards produced from corn stalks were higher than those from cotton stalks, by almost 25%. However significant difference was not observed for internal bonds of boards. Thickness swelling of MDF boards from corn stalks was lower than cotton stalks. Comparing the results obtained with the strength of boards produced from hardwoods showed similarity between corn stalks and wood, but the strength of MDF boards from cotton stalks was lower. However, the results almost satisfied the EN 622-5;1997 requirement.

Low resin medium density fiberboard made from chemical activated hardwoods fibers

This study was conducted to determine properties of medium density fiberboards (MDF) made from treated hardwoods fiber furnishes containing different amounts of two oxidizers, and the addition of limited amounts of synthetic resin. The effects of urea–formaldehyde (UF) resin content (two levels as 5 and 7%), oxidizer type (nitric acid and potassium dichromate), and oxidizer percent (three different levels as 4, 6, and 8%) on some static mechanical and physical properties of dry process interior grade MDF such as modulus of rupture (MOR), and modulus of elasticity (MOE) in bending in dry condition, compression-shear strength (CSsth), water absorption (WA) and thickness swelling (TS) after 2- and 24-h soaking in cold water were investigated. Thirty six oxidative activated laboratory MDF panels were tested. Test results showed that increasing resin content significantly improved all physical and mechanical properties of treated MDF boards. Nitric acid had better mechanical and physical properties than potassium dichromate. Increasing oxidizer percent improved the physical and mechanical properties of MDF boards. Finally, three-way interaction of variables showed the best values for MOR, MOE and CSsth and WA and TS after 2- and 24-h soaking were discerned for T6 treatment, i.e. the combination of 7% UF resin content together with 8% nitric acid. The properties for T6 met the mechanical strength requirements of ANSI standard (ANSI A208. 2-2002) for 120-grade MDF.