Ammonium Lignosulfonate Adhesives for Particleboards with pMDI and Furfuryl Alcohol as Crosslinkers

Tightening formaldehyde emission limits and the need for more sustainable materials have boosted research towards alternatives to urea-formaldehyde adhesives for wood-based panels. Lignin residues from biorefineries consist of a growing raw material source but lack reactivity. Two crosslinkers were tested for ammonium lignosulfonate (ALS)—bio-based furfuryl alcohol (FOH) and synthetic polymeric 4,4′-diphenylmethane diisocyanate (pMDI). The addition of mimosa tannin to ALS before crosslinking was also evaluated. The derived ALS adhesives were used for gluing 2-layered veneer samples and particleboards. Differential Scanning Calorimetry showed a reduction of curing temperature and heat for the samples with crosslinkers. Light microscopy showed that the FOH crosslinked samples had thicker bondlines and higher penetration, which occurred mainly through vessels. Tensile shear strength values of 2-layered veneer samples glued with crosslinked ALS adhesives were at the same level as the melamine reinforced urea-formaldehyde (UmF) reference. For particleboards, the FOH crosslinked samples showed a significant decrease in mechanical properties (internal bond (IB), modulus of elasticity (MOE), modulus of rupture (MOR)) and thickness swelling. For pMDI crosslinked samples, these properties increased compared to the UmF. Although the FOH crosslinked ALS samples can be classified as non-added-formaldehyde adhesives, their emissions were higher than what can be expected to be sourced from the particles.

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Utilization of Birch Bark as an Eco-Friendly Filler in Urea-Formaldehyde Adhesives for Plywood Manufacturing

Polymers ◽

10.3390/polym13040511 ◽

2021 ◽

Vol 13 (4) ◽

pp. 511

Author(s):

Roman Réh ◽

Ľuboš Krišťák ◽

Ján Sedliačik ◽

Pavlo Bekhta ◽

Monika Božiková ◽

...

Keyword(s):

Bending Strength ◽

Urea Formaldehyde ◽

Formaldehyde Emission ◽

Birch Bark ◽

Gravimetric Analysis ◽

European Standard ◽

Scanning Calorimetry ◽

Wood Processing ◽

Fagus Sylvatica L ◽

Positive Effect

The potential of using ground birch (Betula verrucosa Ehrh.) bark as an eco-friendly additive in urea-formaldehyde (UF) adhesives for plywood manufacturing was investigated in this work. Five-ply plywood panels were fabricated in the laboratory from beech (Fagus sylvatica L.) veneers bonded with UF adhesive formulations comprising three addition levels of birch bark (BB) as a filler (10%, 15%, and 20%). Two UF resin formulations filled with 10% and 20% wheat flour (WF) were used as reference samples. The mechanical properties (bending strength, modulus of elasticity and shear strength) of the laboratory-fabricated plywood panels, bonded with the addition of BB in the adhesive mixture, were evaluated and compared with the European standard requirements (EN 310 and EN 314-2). The mechanical strength of the plywood with the addition of BB in the adhesive mixture is acceptable and met the European standard requirements. Markedly, the positive effect of BB in the UF adhesive mixture on the reduction of formaldehyde emission from plywood panels was also confirmed. Initially, the most significant decrease in formaldehyde release (up to 14%) was measured for the plywood sample, produced with 15% BB. After four weeks, the decrease in formaldehyde was estimated up to 51% for the sample manufactured with 20% BB. The performed differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and derivative thermogravimetry (DTG), also confirmed the findings of the study. As this research demonstrated, BB as a waste or by-product of wood processing industry, can be efficiently utilized as an environmentally friendly, inexpensive alternative to WF as a filler in UF adhesive formulations for plywood manufacturing.

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Particleboards from Recycled Thermally Modified Wood

Forests ◽

10.3390/f12111462 ◽

2021 ◽

Vol 12 (11) ◽

pp. 1462

Author(s):

Ján Iždinský ◽

Zuzana Vidholdová ◽

Ladislav Reinprecht

Keyword(s):

Mechanical Properties ◽

Urea Formaldehyde ◽

Brown Rot ◽

Decay Resistance ◽

Raw Material ◽

Modulus Of Rupture ◽

Negative Effect ◽

Serpula Lacrymans ◽

Thermally Modified Wood ◽

Modified Wood

In recent years, the production and consumption of thermally modified wood (TMW) has been increasing. Offcuts and other waste generated during TMWs processing into products, as well as already disposed products based on TMWs can be an input recycled raw material for production of particleboards (PBs). In a laboratory, 16 mm thick 3-layer PBs bonded with urea-formaldehyde (UF) resin were produced at 5.8 MPa, 240 °C and 8 s pressing factor. In PBs, the particles from fresh spruce wood and mixed particles from offcuts of pine, beech, and ash TMWs were combined in weight ratios of 100:0, 80:20, 50:50 and 0:100. Thickness swelling (TS) and water absorption (WA) of PBs decreased with increased portion of TMW particles, i.e., TS after 24 h maximally about 72.3% and WA after 24 h maximally about 64%. However, mechanical properties of PBs worsened proportionally with a higher content of recycled TMW—apparently, the modulus of rupture (MOR) up to 55.5% and internal bond (IB) up to 46.2%, while negative effect of TMW particles on the modulus of elasticity (MOE) was milder. Decay resistance of PBs to the brown-rot fungus Serpula lacrymans (Schumacher ex Fries) S.F.Gray increased if they contained TMW particles, maximally about 45%, while the mould resistance of PBs containing TMW particles improved only in the first days of test. In summary, the recycled TMW particles can improve the decay and water resistance of PBs exposed to higher humidity environment. However, worsening of their mechanical properties could appear, as well.

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

BioResources ◽

10.15376/biores.16.2.3718-3733 ◽

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.

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Influence of Single/Collective Use of Curing Agents on the Curing Behavior and Bond Strength of Soy Protein-Melamine-Urea-Formaldehyde (SMUF) Resin for Plywood Assembly

Polymers ◽

10.3390/polym11121995 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1995 ◽

Cited By ~ 2

Author(s):

Zhigang Wu ◽

Bengang Zhang ◽

Xiaojian Zhou ◽

Lifen Li ◽

Liping Yu ◽

...

Keyword(s):

Shear Strength ◽

Water Resistance ◽

Protein Hydrolysate ◽

Soybean Protein ◽

Urea Formaldehyde ◽

Curing Temperature ◽

Molar Ratio ◽

Scanning Calorimetry ◽

Curing Agents ◽

Crosslinking Reactions

Soybean protein hydrolysate, melamine, urea, and concentrated formaldehyde were used to synthesize an environmentally friendly soybean protein-melamine-urea-formaldehyde (SMUF) co-condensation resin. (NH4)2SO4, (NH4)2HPO4, (NH4)2HPO4 + (NH4)2SO4, (NH4)2HPO4 + (NH4)2S2O8, and (NH4)2HPO4 + (NH4)2SO4 + (NH4)2S2O8 were employed as curing agents for SMUF resin. The curing and thermal behaviors of the SMUF resin were investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results revealed the following: (1) (NH4)2SO4 alone could not cure the SMUF resin completely; thus, the final shear strength accomplished plywood with the resin was low, and its water resistance was poor, while the adhesive section was loose and porous/brittle after curing. (2) (NH4)2HPO4 could be hydrolyzed to generate H+ and promote SMUF curing, but it could also form polyphosphoric acids, resulting in crosslinking reactions with SMUF in parallel; thereby, the curing properties were improved. (3) When (NH4)2HPO4 + (NH4)2SO4 + (NH4)2S2O8 were engaged collectively as curing agent, the shear strength, water resistance, and heat resistance of SMUF attained were the best possible whereas the curing temperature was decreased and the heat released by curing was elevated substantially, which signifies maximized extent of crosslinking was achieved. Further, the adhesive section exhibited mostly a crosslinking intertexture as demonstrated by means of SEM. Accordingly, this study may serve as a guide for the curing of amino resins, with low-molar ratio of formaldehyde to amine in adhesives, which are applied to plywood production.

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Research Progress of Wood-Based Panels Made of Thermoplastics as Wood Adhesives

Polymers ◽

10.3390/polym14010098 ◽

2021 ◽

Vol 14 (1) ◽

pp. 98

Author(s):

Xianfeng Mo ◽

Xinhao Zhang ◽

Lu Fang ◽

Yu Zhang

Keyword(s):

Production Efficiency ◽

Urea Formaldehyde ◽

Formaldehyde Emission ◽

Raw Material ◽

Research Progress ◽

Formaldehyde Resin ◽

Wood Adhesives ◽

Bonding Structure ◽

Existing Problems ◽

Thermoplastic Resins

When thermoplastic resins such as polyethylene (PE) and polypropylene (PP) are selected as wood adhesives to bond wood particles (fibers, chips, veneers) by using the hot-pressing technique, the formaldehyde emission issue that has long existed in the wood-based panel industry can be effectively solved. In this study, in general, thermoplastic-bonded wood-based panels presented relatively higher mechanical properties and better water resistance and machinability than the conventional urea–formaldehyde resin-bonded wood-based panels. However, the bonding structure of the wood and thermoplastic materials was unstable at high temperatures. Compared with the wood–plastic composites manufactured by the extruding or injection molding methods, thermoplastic-bonded wood-based panels have the advantages of larger size, a wider raw material range and higher production efficiency. The processing technology, bonding mechanism and the performance of thermoplastic-bonded wood-based panels are comprehensively summarized and reviewed in this paper. Meanwhile, the existing problems of this new kind of panel and their future development trends are also highlighted, which can provide the wood industry with foundations and guidelines for using thermoplastics as environmentally friendly adhesives and effectively solving indoor pollution problems.

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Antioxidation Activity of Cysteine and Cystine Prepared from Sheep Wool

Journal of the American Leather Chemists Association ◽

10.34314/jalca.v115i5.3810 ◽

2020 ◽

Vol 115 (5) ◽

pp. 166-175

Author(s):

Ján Matyašovský ◽

Ján Sedliačik ◽

Peter Šimon ◽

Igor Novák ◽

Peter Jurkovič ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Urea Formaldehyde ◽

Reference Sample ◽

Physical And Mechanical Properties ◽

Formaldehyde Emission ◽

Quality Parameters ◽

Scanning Calorimetry ◽

Temperature Function ◽

Antioxidant Efficiency ◽

Antioxidation Activity

Amino acid cysteine and its oxidized dimer form,?cystine, can be found in hair, nails, hoofs, feather, wool, etc. The main focus of this research was the preparation of cysteine and cystine from wool and testing of its antioxidation properties in the reduced and oxidized forms. Preparation technology was optimized on a laboratory scale and the samples were characterized by FTIR-ATR spectroscopy and X-ray photoelectron spectroscopy (XPS). Antioxidation activity of cysteine and cystine was studied in a?polyethylene glycol (PEG) matrix employing the non-isothermal differential scanning calorimetry (DSC). In the data treatment, the Berthelot-Hood equation was chosen as the temperature function. The kinetic parameters enabled the assessment of the induction period of oxidation for application temperatures. For the comparison of the stabilizing effect, the protection factors and antioxidant efficiency were calculated. The results show that the antioxidant activity of the samples depends on the preparation procedure, purity, etc. Protection factors decreased with increasing temperature and decreasing concentration. In the second part of the study, cysteine was tested in its reduced and oxidized form for the model polycondensation system of the urea-formaldehyde formulations. The quality parameters of these adhesive mixtures were verified on wood-based panels to determine formaldehyde emission and physical and mechanical properties. The results showed ca. 44% decrease of formaldehyde emission and increase of the shear strength of glued joint for all modifications in comparison with?the reference sample.

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Thermal and mechanical properties of urea-formaldehyde (UF) resin combined with multiwalled carbon nanotubes (MWCNT) as nanofiller and fiberboards prepared by UF-MWCNT

Holzforschung ◽

10.1515/hf-2014-0038 ◽

2015 ◽

Vol 69 (2) ◽

pp. 199-205 ◽

Cited By ~ 12

Author(s):

Anuj Kumar ◽

Arun Gupta ◽

Korada Viswanathan Sharma

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Multiwalled Carbon Nanotubes ◽

Viscoelastic Properties ◽

Urea Formaldehyde ◽

Formaldehyde Emission ◽

Thermal And Mechanical Properties ◽

Scanning Calorimetry ◽

Multiwalled Carbon ◽

Uf Resin

AbstractThe effect of multiwalled carbon nanotubes (MWCNT) as reinforcement on the properties of urea-formaldehyde (UF) resin and medium-density fiberboards was investigated. MWCNT was added to UF in two concentrations, and the effects were studied by means of differential scanning calorimetry and dynamic mechanical thermal analysis in terms of the curing and viscoelastic properties of the resins. In the presence of MWCNT, the activation energy of the resins was lowered, and their storage modulus and thermal conductivity were enhanced. The formaldehyde emission decreased and mechanical properties increased after addition of MWCNT to UF resin.

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EMBALAGENS CARTONADAS COMO MATÉRIA-PRIMA NA FABRICAÇÃO DE COMPÓSITOS

Nativa ◽

10.31413/nativa.v6i2.4990 ◽

2018 ◽

Vol 6 (2) ◽

pp. 177

Author(s):

Talita Baldin ◽

Maiara Talgatti ◽

Amanda Grassamann da Silveira ◽

Bruna Gabrieli Resner ◽

Elio José Santini

Keyword(s):

Mechanical Properties ◽

Physical Properties ◽

Internal Bond ◽

Urea Formaldehyde ◽

Eucalyptus Grandis ◽

Raw Material ◽

Thickness Swelling ◽

Wood Particles ◽

Sustainable Materials ◽

Waste Particles

O objetivo do presente trabalho foi avaliar o potencial de uso de partículas de resíduos de embalagens cartonadas e partículas de Eucalyptus grandis para a fabricação de compósitos, colados com adesivo à base de ureia-formaldeído. Foram utilizadas cinco diferentes proporções de madeira de E. grandis e embalagens cartonadas. As partículas de madeira e embalagens cartonadas foram produzidas em laboratório. A avaliação da qualidade dos compósitos envolveu a caracterização da geometria das partículas, das propriedades físicas: massa específica básica, teor de umidade de equilíbrio, absorção de água e inchamento em espessura após 2 e 24 horas de imersão em água e das propriedades mecânicas: flexão estática (MOE e MOR), resistência ao arrancamento de parafuso, ligação interna e dureza Janka. A incorporação de partículas de embalagens cartonadas proporcionou uma melhoria nas propriedades físicas em relação aos compósitos puros de madeira. Já para as propriedades mecânicas, compósitos com até 50% de embalagens cartonadas obtiveram melhores resultados, no entanto, a incorporação a partir de 75% ocasionou decadência nessas propriedades. Compósitos de madeira de E. grandis e embalagens cartonadas apresentaram potencial para utilização em ambientes internos e podem ser uma alternativa para a produção de compósitos sustentáveis e de boa qualidade.Palavra-chave: materiais sustentáveis, propriedades físicas e mecânicas, ureia-formaldeído. CARTONBOARD PACKAGING AS A RAW MATERIAL IN THE MANUFACTURE OF COMPOSITES ABSTRACT:The aim of this study was to evaluate the potential waste particles use of carton packaging and particles of E. grandis for the manufacture of particle boards, bonded with urea-formaldehyde-based adhesive. Five different proportions of E. grandis wood and cartons have been used. The wood particles and cartons were produced in the laboratory. The quality assessment panels involved characterizing the geometry of the particles, the physical properties: specific gravity, equilibrium moisture content, water absorption and thickness swelling after 2 and 24 hours of immersion in water and mechanical properties: flexural static (MOR and MOE), resistance to screw pullout, internal bond and Janka hardness. The incorporation of particulate cartons provided an improvement in physical properties relative to pure wood panels. As for the mechanical properties, panels of up to 50 % of cartons obtained best results, however, incorporating from 75 % decay caused these properties. The wood particleboard of E. grandis and cartons showed potential for use indoors and become an alternative for producing sustainable panels and of good quality.Keywords: sustainable materials, physical-mechanical properties; urea-formaldehyde. DOI:

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Effect of Mineral Composite Fillers on Properties of Man-Made Plywood

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.178.97 ◽

2010 ◽

Vol 178 ◽

pp. 97-102 ◽

Cited By ~ 1

Author(s):

Hong Xia Shao ◽

Qing Guo Tang ◽

Jin Sheng Liang ◽

Yan Ding

Keyword(s):

Indoor Environment ◽

Composite Powder ◽

Urea Formaldehyde ◽

Formaldehyde Emission ◽

Raw Material ◽

National Standard ◽

Formaldehyde Resin ◽

Powder Filler ◽

Modified Attapulgite ◽

Mineral Powder

Attapulgite mineral powder as raw material, through surface modification and composite of various mineral processing, the effect of modifier dosage, composite powder filler ratio on the mechanical properties and formaldehyde emission of the plywood which is bonded by filled urea-formaldehyde resin were investigated. The results show that under the conditions of the plywood bonding strength to meet the national standard, modified attapulgite make the plywood formaldehyde emission decrease from 4.5 to 2.1 mg/L, the composite material can make the formaldehyde emission decreased to 1.6 mg/L, which can improved the indoor environment and the grade of plywood.

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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.

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