Reducing free formaldehyde emission, improvement of thickness swelling and increasing storage stability of novel medium density fiberboard by urea-formaldehyde adhesive modified by phenol derivatives

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

Synthesis of Lignin-Based Polyacid Catalyst and Its Utilization to Improve Water Resistance of Urea–formaldehyde Resins

Polymers ◽

10.3390/polym12010175 ◽

2020 ◽

Vol 12 (1) ◽

pp. 175 ◽

Cited By ~ 4

Author(s):

Shishuai Gao ◽

Yupeng Liu ◽

Chunpeng Wang ◽

Fuxiang Chu ◽

Feng Xu ◽

...

Keyword(s):

Maleic Anhydride ◽

13C Nmr ◽

Water Resistance ◽

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Formaldehyde Emission ◽

Medium Density ◽

1H And 13C Nmr ◽

Uf Resin ◽

Improve Water Resistance

In this study, a lignin-based polyacid catalyst was synthesized via two steps to enhance water resistance of urea–formaldehyde (UF) resins. The first steps involved a hydroxymethylation reaction to increase the hydroxyl content in lignin. Then, hydroxymethylated lignins were reacted with maleic anhydride to form maleated lignin-based polyacids. The acid groups were expected to function as acid catalysts to catalyze the curing process of UF resin. In order to elucidate the structural variation, 3-methoxy-4-hydroxyphenylpropane as a typical guaiacol lignin structural unit was used as a model compound to observe the hydroxymethylation and the reaction with maleic anhydride analyzed by 1H and 13C NMR. After the structural analysis of synthesized lignin-based polyacid by FTIR and 13C NMR, it was used to produce UF resin as an adhesive in plywood and medium density fiberboard (MDF) production, respectively. The results showed that when the addition of lignin-based polyacid was 5% in plywood, it could effectively improve the water resistance of UF resins as compared to commercial additive NH4Cl. It also exhibited a lower formaldehyde emission. Like plywood, lignin-based catalysts used in medium density fiberboard production could not only maintain the mechanical properties, but also inhibit the water adsorption of fiberboards.

Download Full-text

Decreasing formaldehyde emission from medium density fiberboard panels produced by adding different amine compounds to urea formaldehyde resin

International Journal of Adhesion and Adhesives ◽

10.1016/j.ijadhadh.2011.06.011 ◽

2011 ◽

Vol 31 (7) ◽

pp. 674-678 ◽

Cited By ~ 70

Author(s):

S. Boran ◽

M. Usta ◽

E. Gümüşkaya

Keyword(s):

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Formaldehyde Emission ◽

Urea Formaldehyde Resin ◽

Formaldehyde Resin ◽

Medium Density ◽

Amine Compounds

Download Full-text

Tuning of adhesion and disintegration of oxidized starch adhesives for the recycling of medium density fiberboard

BioResources ◽

10.15376/biores.15.3.5156-5178 ◽

2020 ◽

Vol 15 (3) ◽

pp. 5156-5178

Author(s):

Muhammad Adly Rahandi Lubis ◽

Byung-Dae Park ◽

Min-Kug Hong

Keyword(s):

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Physical And Mechanical Properties ◽

Formaldehyde Emission ◽

Molar Ratio ◽

Medium Density ◽

Molar Ratios ◽

Oxidized Starch ◽

Cross Linker ◽

The Cross

Oxidized starch (OS) adhesives with a balance between their adhesion and disintegration properties were prepared by controlling the degree of oxidation and modifying the cross-linker type and level to replace urea-formaldehyde (UF) resins for easy recycling of medium density fiberboard (MDF). Four molar ratios of H2O2/starch, two types of cross-linker, i.e., blocked-pMDI (B-pMDI) and citric acid (CA), and three levels of the cross-linkers were employed to tailor the performance of the OS adhesives. The OS reacted with the isocyanate groups from the B-pMDI to form amide linkages, while it formed ester linkages by reacting with the CA. The resulting B-pMDI/OS-bonded MDF had better physical and mechanical properties than the CA/OS-bonded MDF, with comparable adhesion (0.34 MPa) to UF resins and ten times greater degree of fiber disintegration than UF resins. The combination of a 0.5 molar ratio OS with 7.5 wt% of B-pMDI produced MDF exhibiting an optimal balance between adhesion and disintegration, suggesting that such OS adhesives could someday replace UF resins in manufacturing and recycling of MDF without formaldehyde emission.

Download Full-text

Effect of Iron Oxide Nanoparticles on the Physical Properties of Medium Density Fiberboard

Polymers ◽

10.3390/polym12122911 ◽

2020 ◽

Vol 12 (12) ◽

pp. 2911 ◽

Cited By ~ 2

Author(s):

Waheed Gul ◽

Hussein Alrobei ◽

Syed Riaz Akbar Shah ◽

Afzal Khan

Keyword(s):

Iron Oxide ◽

Physical Properties ◽

Iron Oxide Nanoparticles ◽

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Oxide Nanoparticles ◽

Medium Density ◽

Fe2o3 Nanoparticles ◽

Thickness Swelling ◽

Composite Samples

This paper investigates the influence of iron oxide (Fe2O3) nanoparticles on the physical properties of medium density fiberboard (MDF). In this study, three different nano iron oxide loadings, i.e., 0.5, 1.5 and 2.5 wt %, and untreated poplar fibers were used. The iron oxide (Fe2O3) nanoparticles were initially dispersed into urea formaldehyde resin using a high-vacuum mechanical stirrer before being incorporated into natural fibers. The untreated poplar fibers were wound onto metal frames to produce dry mat layers. Twenty different composite samples were made. All composite samples were tested for physical properties, i.e., thickness swelling, water absorption, moisture content and density in accordance with standards EN-317, ASTM D570, EN-322 and EN-323 respectively. Based on the results, it was found that the incorporation of homogeneously dispersed iron oxide nanoparticles significantly improved thickness swelling (Ts). Moreover, water absorption (WA) improved by up to 49.18 and 34.54%, respectively, at the highest loading of 2.5 wt %. Microstructure was investigated and characterized with scanning electron microscopy (SEM), x-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) and we examined whether iron oxide nanoparticles exhibit good interactions with urea formaldehyde and poplar wood fibers. Heat and mass transfer investigation in the form of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) was carried out due to the impact of Fe2O3 nanoparticles. The curing temperature and thermal stability of the resin were enhanced due to the addition of Fe2O3 nanoparticles. A one-way ANOVA statistical analysis was established to effectively control the use of Fe2O3 nanoparticles. Therefore, the presence of iron oxide nanoparticles in an epoxy polymer contributes to a stiffer matrix that, effectively, enhances the capability of improving the physical properties of nano MDF.

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 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

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

BioResources ◽

10.15376/biores.15.4.7918-7932 ◽

2020 ◽

Vol 15 (4) ◽

pp. 7918-7932

Author(s):

Osman Camlibel

Keyword(s):

Internal Bond ◽

Medium Density Fiberboard ◽

Formaldehyde Emission ◽

Wood Chips ◽

Medium Density ◽

Wood Fibers ◽

Thickness Swelling ◽

Fiber Production ◽

Lignocellulosic Fibers ◽

Potential Component

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.

Download Full-text

Characterization of Zinc Oxide-Urea Formaldehyde Nano Resin and Its Impact on the Physical Performance of Medium-Density Fiberboard

Polymers ◽

10.3390/polym13030371 ◽

2021 ◽

Vol 13 (3) ◽

pp. 371

Author(s):

Waheed Gul ◽

Syed Shah ◽

Afzal Khan ◽

Catalin Pruncu

Keyword(s):

Zinc Oxide ◽

Water Absorption ◽

Physical Performance ◽

Zno Nanoparticles ◽

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Research Work ◽

Medium Density ◽

Thickness Swelling ◽

Absorption Properties

The main purpose of this research work is to characterize zinc oxide-urea formaldehyde nano resin and identify the physical performance of medium-density fiberboard (MDF). Considering the dry weight of natural fibers, the ZnO nanoparticles were added to urea formaldehyde (UF) glue at four levels—0.0%, 1.0%, 2.0% and 3.0%—and their effects were investigated in terms of the physical properties of MDF. The surface morphology and crystalline structure of ZnO, UF and UF-ZnO nanofillers were characterized using Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) analysis and significant improvements were achieved as a result of the addition of nanoparticles. Thermal properties were analyzed by means of differential scanning calorimetry (DSC) and thermogravemetric analysis (TGA) and it was observed that increasing the concentration of ZnO nanoparticles ultimately enhanced the curing of UF-ZnO nanofillers. Finally, density, thickness swelling and water absorption properties were investigated and it was observed that thickness swelling and water absorption properties were improved by 38% and 12%, respectively, when compared to control MDF.

Download Full-text

Calcium carbonate modified urea–formaldehyde resin adhesive for strength enhanced medium density fiberboard production

RSC Advances ◽

10.1039/d1ra04316a ◽

2021 ◽

Vol 11 (40) ◽

pp. 25010-25017

Author(s):

Li Lu ◽

Yan Wang ◽

Tianhua Li ◽

Supeng Wang ◽

Shoulu Yang ◽

...

Keyword(s):

Calcium Carbonate ◽

Urea Formaldehyde ◽

Medium Density Fiberboard ◽

Urea Formaldehyde Resin ◽

Formaldehyde Resin ◽

Medium Density ◽

Ionic Bond ◽

Resin Adhesive ◽

Uf Resin ◽

Modified Urea

Reactions between CaCO3 and CH2O2 during polycondensation of UF resin produce Ca2+. Ionic bond complexation binds Ca2+ with UF resin. The UF resin crystalline percentage decreases from 26.86% to 22.71%. IB strength of resin bonded fiberboard increases from 0.75 to 0.94 MPa.

Download Full-text