Analyzing the Modulus of Rupture of Medium Density Fiberboard Subjected to Outdoor Exposure for 21 Years

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.

Download Full-text

Effect of juvenile wood on strength properties and dimensional stability of black spruce medium-density fiberboard panels

Holzforschung ◽

10.1515/hf.2005.001 ◽

2005 ◽

Vol 59 (1) ◽

pp. 1-9 ◽

Cited By ~ 9

Author(s):

Jun Li Shi ◽

Shu Yin Zhang ◽

Bernard Riedl

Keyword(s):

Water Absorption ◽

Dimensional Stability ◽

Juvenile Wood ◽

Black Spruce ◽

Medium Density Fiberboard ◽

Strength Properties ◽

Analysis Of Covariance ◽

Modulus Of Rupture ◽

Medium Density ◽

Mean Values

Abstract Strength properties and dimensional stability of medium-density fiberboard (MDF) panels made from black spruce (Picea mariana [Mill.] BSP.) 0–20, 21–40, and over 40 year old fiber were studied. An analysis of covariance (ANCOVA) was performed to examine the differences in modulus of rupture (MOR), modulus of elasticity (MOE), and thickness swell (TS) of the three types of panels, while panel density was treated as a covariate in order to adjust the mean values that were partly attributed to panel density. The results indicate that MOR, internal bond (IB), and water absorption of MDF panels made from 0–20 year old fiber, which contained 100% juvenile wood, were significantly superior to those of panels made from 21–40 and over 40 year old fiber; but linear expansion (LE) of MDF panels made from 0–20 year old fiber was significantly larger than that of panels from the other two age classes. The differences in MOR, IB, water absorption, and LE between panels made from 21–40 and over 40 year old fiber were not significant. The comparisons of panel MOE and TS were relatively dependent on panel density due to existence of interactions among the three age groups.

Download Full-text

Durability of Medium Density Fiberboard Subjected to Outdoor Exposure

Mokuzai Gakkaishi ◽

10.2488/jwrs.58.347 ◽

2012 ◽

Vol 58 (6) ◽

pp. 347-356 ◽

Cited By ~ 7

Author(s):

Hideaki Korai

Keyword(s):

Medium Density Fiberboard ◽

Outdoor Exposure ◽

Medium Density

Download Full-text

Effect of Embedment of MWCNTs for Enhancement of Physical and Mechanical Performance of Medium Density Fiberboard

Nanomaterials ◽

10.3390/nano11010029 ◽

2020 ◽

Vol 11 (1) ◽

pp. 29

Author(s):

Waheed Gul ◽

Hussein Alrobei ◽

Syed Riaz Akbar Shah ◽

Afzal Khan ◽

Abid Hussain ◽

...

Keyword(s):

Mechanical Performance ◽

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Research Work ◽

Multiwall Carbon Nanotubes ◽

Physical And Mechanical Properties ◽

Formaldehyde Emission ◽

Modulus Of Rupture ◽

Formaldehyde Resin ◽

Medium Density

In this research work effect of embedment of multiwall carbon nanotubes (MWCNTs) on the physical and mechanical properties of medium density fiberboard (MDF) have been investigated. The MWCNTs were embedded in urea formaldehyde resin (UF) at 0, 1.5%, 3% and 5% concentrations by weight for the manufacturing of nano-MDF. The addition of these nanoparticles enhanced thermal conductivity by 24.2% reduced curing time by 20% and controlled formaldehyde emission by 59.4%. The internal bonding (I.B), modulus elasticity (MOE), modulus of rupture (MOR), thickness swelling (Ts) and water absorption (WA) properties were improved significantly by 21.15%, 30.2%, 28.3%, 44.8% and 29% respectively as compared to controlled MDF.

Download Full-text

Effect of Alumina Nano-Particles on Physical and Mechanical Properties of Medium Density Fiberboard

Materials ◽

10.3390/ma13184207 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4207 ◽

Cited By ~ 2

Author(s):

Hisham Alabduljabbar ◽

Rayed Alyousef ◽

Waheed Gul ◽

Syed Riaz Akbar Shah ◽

Afzal Khan ◽

...

Keyword(s):

Mechanical Properties ◽

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Thermo Gravimetric Analysis ◽

Physical And Mechanical Properties ◽

Nano Particles ◽

Modulus Of Rupture ◽

Alumina Nanoparticles ◽

Gravimetric Analysis ◽

Medium Density

This research aims to explore the effects of nanoparticles such as alumina (Al2O3) on the physical and mechanical properties of medium density fiberboards (MDF). The nanoparticles are added in urea-formaldehyde (UF) resin with different concentration levels e.g., 1.5%, 3%, and 4.5% by weight. A combination of forest fibers such as Populus Deltuidess (Poplar) and Euamericana (Ghaz) are used as a composite reinforcement due to their exceptional abrasion confrontation as well as their affordability and economic value with Al2O3-UF as a matrix or nanofillers for making the desired nanocomposite specimens. Thermo-gravimetric analysis (TGA) and thermal analytical analysis (TAA) in the form of differential scanning calorimetry (DSC) are carried out and it has been found that increasing the percentage of alumina nanoparticles leads to an increase in the total heat content. The mechanical properties such as internal bonding (IB), modulus of elasticity (MOE) and modulus of rupture (MOR), and physical properties such as density, water absorption (WA), and thickness swelling (TS) of the specimens have been investigated. The experimental results showed that properties of the new Nano-MDF are higher when compared to the normal samples. The results also showed that increasing the concentration of alumina nanoparticles in the urea-formaldehyde resin effects the mechanical properties of panels considerably.

Download Full-text

Effect of Graphene Oxide Nanoparticles on the Physical and Mechanical Properties of Medium Density Fiberboard

Polymers ◽

10.3390/polym13111818 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1818

Author(s):

Waheed Gul ◽

Hussein Alrobei

Keyword(s):

Mechanical Properties ◽

Graphene Oxide ◽

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Physical And Mechanical Properties ◽

Modulus Of Rupture ◽

Formaldehyde Resin ◽

Oxide Nanoparticles ◽

Medium Density ◽

Thickness Swelling

In this research, the special effects of graphene oxide nanoparticle charging (0, 2, 4, 6, wt.%) on the properties of medium-density fiberboard were examined. Physical and mechanical properties of the panels were determined conferring the method of European Norm standards. The consequences exhibited substantial enhancement in mechanical properties, explicitly in modulus of rupture, modulus of elasticity and internal bonding for 2–6% nanoparticle addition in a urea–formaldehyde resin. The mechanical properties, i.e., internal bond, modulus of elasticity and modulus of rupture were improved by 28.5%, 19.22% and 38.8%, respectively. Results also show a clear enhancement in thickness swelling and water absorption. The physical properties of thickness swelling, water absorption and thermal conductivity were improved up to 50%, 19.5% and 39.79%, respectively. The addition of graphene oxide nanoparticles strongly affected the curing time of the urea–formaldehyde resin and improved its thermal stability.

Download Full-text

Monitoring Resin Cure Of Medium Density Fiberboard Using Dielectric Sensors

MRS Proceedings ◽

10.1557/proc-430-601 ◽

1996 ◽

Vol 430 ◽

Cited By ~ 1

Author(s):

R. J. King ◽

R. W. Rice

Keyword(s):

Dielectric Constant ◽

Real Time ◽

Wood Density ◽

Complex Permittivity ◽

Loss Factor ◽

Phenol Formaldehyde ◽

Medium Density Fiberboard ◽

Modulus Of Rupture ◽

Curing Process ◽

Medium Density

AbstractFlush mounted, in-press microwave (600–800 MHz) sensors have been developed for monitoring the complex permittivity in real time during the cure of medium density fiberboard. The measured dielectric constant (ε')a nd loss factor (ε") are independent diagnostic indicators of dynamic cure events that are catalyzed by heat, pressure and moisture. In particular, with this technique the instantaneous effects of resin viscosity, rate and degree of adhesive cure, the wood density, the changes in phase of the moisture and the rate of moisture depletion can be monitored during the entire curing process.The comparative roles of moisture and adhesive content are discussed, along with the comparative modulus of rupture with cure duration. Results are presented comparing the dynamics of phenol-formaldehyde and isocyanate resins.

Download Full-text

Degradation of Medium Density Fibreboard and Particleboard Mechanical Performance after Exposed to Different Environmental Condition

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b1104.0782s419 ◽

2019 ◽

Vol 8 (2S4) ◽

pp. 528-532 ◽

Cited By ~ 1

Keyword(s):

Mechanical Performance ◽

Water Immersion ◽

Medium Density Fiberboard ◽

Degradation Process ◽

Modulus Of Rupture ◽

Medium Density ◽

Ambient Exposure ◽

Board Thickness ◽

Board Type ◽

Exposure Conditions

Wood or natural-based products will continue to be susceptible to degradation. However, this degradation process can be slow-down by introducing additives or certain treatment. The properties (i.e. mechanical, physical, bonding etc.) of wood-based panel such as Medium Density Fiberboard (MDF) and Particleboard (PB) degrades in function with period of usage or exposure due to factors in surrounding conditions. This work focuses on the study of mechanical performance deterioration for MDF and PB after condition in the air-conditioned room and ambient for three months. Through this study, comparisons of various board variables (board types, exposure conditions, board thicknesses, resin types) influences the board performance degradation process. The project also studied the effects of cold-water immersion (12, 24 and 72 hours) to the mechanical properties of the board. The mechanical performance of boards was evaluated based on static bending (Modulus of Elasticity and Modulus of Rupture) and internal bonding tests after exposed for 3 months. All boards (MDF and PB) used in this study were obtained from local commercial panel manufacturer and test according to JIS A 5908-1994. The findings show that all the variables studied: exposure conditions, resin type, board thickness and board type respectively, have a significant effect on the diminished strength of panel strengths. The conditioning method and board type found to influence foremost compared with resin type. Exposing both of panels in air-conditioned room found to delay the degradation compared with ambient exposure for tested properties; MOE, MOR and IB respectively. The board thickness seems influenced the degradation of the board in any exposure

Download Full-text

Natural Aging in Heat-Treated Medium-Density Fiberboard Panels

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.634.473 ◽

2014 ◽

Vol 634 ◽

pp. 473-478

Author(s):

Stefânia Lima Oliveira ◽

Rafael Farinassi Mendes ◽

Ticyane Pereira Freire ◽

Lourival Marin Mendes

Keyword(s):

Heat Treatment ◽

Bending Strength ◽

Treatment Time ◽

Medium Density Fiberboard ◽

Natural Aging ◽

Modulus Of Rupture ◽

Control Treatment ◽

Medium Density ◽

Promising Alternative ◽

Heat Treated

Heat treatment of wood is a promising alternative in improving its dimensional stability. The action of heat ensures the good quality of the treated wood product, with better performance in environments with high humidity. To prove the positive effect of this treatment, a test in which the specimens are weathered for a certain period of time termed as natural aging was performed. The aim of this study was to evaluate the effect of aging on heat-treated medium-density fiberboard (MDF) panels. Commercial MDF panels produced with pinewood adhesive and urea-formaldehyde were used. The experiment included seven test treatments [at 200, 225, and 250°C heat temperatures for 5 and 10 min] and a control treatment (without heat treatment). The products subjected to these treatments were weathered for 40 days, and climatological data were monitored daily. The results suggested that: 1) There is a decreasing trend in density with increasing time and temperature; 2) the treatment time and temperature had no effect on the ownership of the static bending for modulus of elasticity (MOE); 3) the time period is correlated with the treatment temperature for modulus of rupture (MOR) property; and 4) the thermal treatment of MDF panels did not allow the maintenance of the properties of MOR and MOE static bending strength after natural aging.

Download Full-text

Impact of Hot Pressing Temperature on Medium Density Fiberboard (MDF) Performance

Advances in Materials Science and Engineering ◽

10.1155/2017/4056360 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 11

Author(s):

W. Gul ◽

A. Khan ◽

A. Shakoor

Keyword(s):

Thermal Energy ◽

Hot Pressing ◽

Production Efficiency ◽

Water Resistance ◽

Medium Density Fiberboard ◽

Modulus Of Rupture ◽

Medium Density ◽

Hot Press ◽

Pressing Temperature ◽

Actual Use

Hot pressing temperature is determined according to the performance of boards, type of glue, and production efficiency of hot press. During hot pressing, the thermal energy has enhanced the plasticity of the fiber and created conditions for the integration of different bonds. The thermal energy will cause the moisture in raw board to vaporize. Temporary heating will expedite the solidification of hot set resin for decreased friction and increased fluidity. The hot pressing temperature usually refers to the temperature of hot pressing plate, but what plays function in actual use is the temperature inside the raw board. This research investigates the performance of MDF with respect to hot pressing temperature. The strength and water resistance of the product are improved with the increase of hot pressing temperature from 140°C to 160°C, the Modulus of Rupture (MOR) is increased by 9.8%, the Internal Bonding (IB) is increased by 33.6%, the water absorption (Wt) is decreased by 38.2%, and the thickness expansion rate (Ts) is decreased by 15.2%.

Download Full-text