Potential of pulp and paper sludge as a formaldehyde scavenger agent in MDF resins

Holzforschung ◽  
2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Sébastien Migneault ◽  
Ahmed Koubaa ◽  
Bernard Riedl ◽  
Hamid Nadji ◽  
James Deng ◽  
...  
Keyword(s):  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Length Distribution ◽  
Formaldehyde Emission ◽  
Buffering Capacity ◽  
Pulp And Paper ◽  
Adhesive Properties ◽  
Bending Performance ◽  
Fiber Length Distribution ◽  
Uf Resin

Abstract Sludge of pulp and paper mills have natural adhesive properties. The primary sludge (PS, contains fibers) and secondary sludge (SS, contains proteins) could also be suitable for manufacturing medium-density fiberboard (MDF). Protein in SS can react with formaldehyde (HCHO), and as an additive in urea-formaldehyde (UF) resins it can reduce formaldehyde emission. Thus, SS was investigated in the present study. PS and SS were collected from two mills and characterized in terms of chemical composition, fiber length distribution, pH, and buffering capacity. MDF samples were processed according to an experimental design, in which UF resin content was reduced from 12% to 8% and replaced by SS in the range of 5%–15%. Gel time measurement showed high SS reactivity with UF resin. The SS reduced HCHO emissions by up to 68% compared to control panels, without compromising internal bond strength. The bonding effect of SS was lower than expected due to the high pH, thus the buffering capacity reduced UF performance. Moreover, sludge reduced bending performance. Dimensional stability was the greatest disadvantage of sludge panels.

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

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 175 ◽  
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.

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

RSC Advances ◽  
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.

Effect of wood acidity and catalyst on UF resin gel time

Holzforschung ◽  
2004 ◽  
Vol 58 (4) ◽  
pp. 408-412 ◽  
Author(s):  
C. Xing ◽  
S.Y. Zhang ◽  
J. Deng
Keyword(s):  
Ph Value ◽  
Raw Materials ◽  
Urea Formaldehyde ◽  
Acid Catalyst ◽  
Buffering Capacity ◽  
Raw Material ◽  
Gel Time ◽  
Uf Resin ◽  
Effects Of Ph ◽  
Fiber Materials

Abstract Knowledge of pH and buffering capacity of raw fiber materials is important for understanding the effects of raw material on the curing rate of urea formaldehyde (UF) resin, used for panel manufacturing, especially with some less-desirable wood materials such as bark, top, and commercial thinnings. The effects of pH and buffering capacity as well as catalyst content on the gel time of UF resin were investigated. The results obtained from this study indicate that bark has a lower pH value as well as higher acid and alkaline buffering capacities than wood of the same species due to their extractives. The pH values of the raw fiber materials studied decrease with increased absolute and relative acid buffering capacity due to the increased absolute acidity mass in the solution. At lower levels of added catalyst, the effect of raw material pH on UF resin gel time is significant, while it is insignificant at higher catalyst contents. This may be due to the acidity of wood, which is the main acid catalyst source of the mixture at lower levels of added catalyst, while at higher levels, catalyst is the main source. With higher catalyst contents, all studied raw materials mixed with UF resin result in a longer gel time than does UF resin alone.

Preparation and Characteristic of Urea Formaldehyde Modified with Hexamethoxymethyl Melamine

2010 ◽  
Vol 160-162 ◽  
pp. 1245-1252
Author(s):  
Zhen Zhong Gao ◽  
Li Tao Guan ◽  
Jin Sun ◽  
Deng Yun Tu
Keyword(s):  
Bond Strength ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Solidification Time ◽  
Uf Resin ◽  
Optimum Formulation ◽  
Chinese Standard

Hexamethoxymethyl melamine (HMMM) was used to modify UF resins to obtain good performance with low formaldehyde emission. The effect of urea to formaldehyde ratio, HMMM content on the properties of UF resin was studied in detail. The results suggested that urea to formaldehyde ratio to be 1:0.9 and 20% HMMM content is the optimum formulation to afford desired UF resin. The viscosity, solidification time, bond strength and formaldehyde emission of the modified UF resins were also studied. The results revealed that the performance of the modified UF achieved the chinese standard.

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

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3718-3733
Author(s):  
Osman Camlibel
Keyword(s):  
Liquid Paraffin ◽  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Formaldehyde Emission ◽  
Modulus Of Rupture ◽  
Medium Density ◽  
Wood Fibers ◽  
Hot Press ◽  
Ammonium Sulphate Solution ◽  
Hot Press Process

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.

scholarly journals Potential Use of Wollastonite as a Filler in UF Resin Based Medium-Density Fiberboard (MDF)

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1435 ◽  
Author(s):  
Hamid R. Taghiyari ◽  
Ayoub Esmailpour ◽  
Roya Majidi ◽  
Jeffrey J. Morrell ◽  
Mohammad Mallaki ◽  
...  
Keyword(s):  
Bond Strength ◽  
Internal Bond ◽  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Medium Density ◽  
Environmental Footprint ◽  
Positive Effects ◽  
Uf Resin ◽  
Resin Curing ◽  
Potential Use

Urea-formaldehyde (UF) resins are primary petroleum-based, increasing their potential environmental footprint. Identifying additives to reduce the total amount of resin needed without adversely affecting the panel properties could reduce these impacts. Wollastonite is a mineral containing calcium and silica that has been used as an additive in a variety of materials and may be useful as a resin extender. Nanoscale wollastonite has been shown to enhance the panel properties but is costly. Micron-scale wollastonite may be a less costly alternative. Medium-density fiberboards were produced by blending a hardwood furnish with UF alone, micron-sized wollastonite alone, or a 9:1 ratio of UF to wollastonite. Panels containing of only wollastonite had poor properties, but the properties of panels with 9:1 UF/wollastonite were similar to the UF-alone panels, except for the internal bond strength. The results suggest that small amounts of micron-sized wollastonite could serve as a resin extender. Further studies are suggested to determine if the micron-sized material has similar positive effects on the resin curing rate.

The Impact of Different Dosage of Additives on the UF Resin Used in Plywood

2011 ◽  
Vol 197-198 ◽  
pp. 147-150 ◽  
Author(s):  
Wei Wang ◽  
Li Bin Zhu ◽  
Ji You Gu ◽  
Xiang Li Weng ◽  
Hai Yan Tan
Keyword(s):  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Synthetic Process ◽  
Resin Adhesive ◽  
Environmental Friendly ◽  
Uf Resin ◽  
Comprehensive Performance ◽  
The Impact

Through the study of the effects of different dosage of additives on the properties of urea formaldehyde resin adhesive prepared at low mole ratio of formaldehyde/urea, optimize the synthetic process of the UF resin which is used at the E0 grade plywood. The results showed that the product synthesized under the following condition: the mole ratio of formaldehyde/urea is 0.99:1, the dosage of the specific additive is 1.0% and that of melamine is 3-4%, had a good comprehensive performance and the formaldehyde emission of the plywood meets the E0 grade which is environmental-friendly.

scholarly journals Reduction of formaldehyde emission from urea-formaldehyde resin with a small quantity of graphene oxide

RSC Advances ◽  
2021 ◽  
Vol 11 (52) ◽  
pp. 32830-32836
Author(s):  
Kazuki Saito ◽  
Yasushi Hirabayashi ◽  
Shinya Yamanaka
Keyword(s):  
Graphene Oxide ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Uf Resin

This is the first experiment to demonstrate that GO effectively prevents formaldehyde emission from UF resin.

scholarly journals Urea Formaldehyde Resin Resultant Plywood with Rapid Formaldehyde Release Modified by Tunnel-Structured Sepiolite

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1286 ◽  
Author(s):  
Li ◽  
Gao ◽  
Xia ◽  
Li ◽  
Zhou
Keyword(s):  
Shear Strength ◽  
Fracture Surface ◽  
Cross Section ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Formaldehyde Resin ◽  
Tunnel Structure ◽  
Formaldehyde Release ◽  
Uf Resin ◽  
The Cost

In order to reduce the cost of plywood and save edible resources (wheat flour), a cheap and resourceful clay, sepiolite, was used to modify urea formaldehyde (UF) resin. The performances of filler-filled UF resins were characterized by measuring the thermal behavior, cross section, and functional groups. Results showed that cured UF resin with SEP (sepiolite) formed a toughened fracture surface, and the wet shear strength of the resultant plywood was maximum improved by 31.4%. The tunnel structure of SEP was beneficial to the releasing of formaldehyde, as a result, the formaldehyde emission of the plywood bonded by UF resin with SEP declined by 43.7% compared to that without SEP. This study provided a new idea to reduce the formaldehyde emission, i.e. accelerating formaldehyde release before the product is put into use.

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