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

Polymers ◽  
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.

scholarly journals Properties of High-Density Fiberboard Bonded with Urea–Formaldehyde Resin and Ammonium Lignosulfonate as a Bio-Based Additive

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2775 ◽  
Author(s):  
Petar Antov ◽  
Viktor Savov ◽  
Neno Trichkov ◽  
Ľuboš Krišťák ◽  
Roman Réh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Thermal Analyses ◽  
Formaldehyde Emission ◽  
High Density ◽  
Formaldehyde Resin ◽  
Gravimetric Analysis ◽  
Wood Fibers ◽  
Uf Resin

The potential of ammonium lignosulfonate (ALS) as an eco-friendly additive to urea–formaldehyde (UF) resin for manufacturing high-density fiberboard (HDF) panels with acceptable properties and low free formaldehyde emission was investigated in this work. The HDF panels were manufactured in the laboratory with very low UF resin content (4%) and ALS addition levels varying from 4% to 8% based on the mass of the dry wood fibers. The press factor applied was 15 s·mm−1. The physical properties (water absorption and thickness swelling), mechanical properties (bending strength, modulus of elasticity, and internal bond strength), and free formaldehyde emission were evaluated in accordance with the European standards. In general, the developed HDF panels exhibited acceptable physical and mechanical properties, fulfilling the standard requirements for HDF panels for use in load-bearing applications. Markedly, the laboratory-produced panels had low free formaldehyde emission ranging from 2.0 to 1.4 mg/100 g, thus fulfilling the requirements of the E0 and super E0 emission grades and confirming the positive effect of ALS as a formaldehyde scavenger. The thermal analyses performed, i.e., differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and derivative thermogravimetry (DTG), also confirmed the main findings of the research. It was concluded that ALS as a bio-based, formaldehyde-free adhesive can be efficiently utilized as an eco-friendly additive to UF adhesive formulations for manufacturing wood-based panels under industrial conditions.

Exploitation of liquefied wood waste for binding recycled wood particleboards

Holzforschung ◽  
2016 ◽  
Vol 70 (12) ◽  
pp. 1135-1138 ◽  
Author(s):  
Dominika Janiszewska ◽  
Iwona Frąckowiak ◽  
Karolina Mytko
Keyword(s):  
Mechanical Properties ◽  
Industrial Waste ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
European Standard ◽  
Formaldehyde Content ◽  
Wood Processing ◽  
Uf Resin ◽  
Liquefied Wood ◽  
Standard Quality

Abstract Four types of industrial waste from wood processing, namely a mixed hardwood-softwood powder, pine and beech sawdust, and bark were liquefied and tested as binders for particleboards (PB) made of recycled wood. The liquefaction reaction was carried out at elevated temperature with a mixture of solvents from polyhydroxyl alcohols such as glycerine and propylene glycol, and p-toluenesulfonic acid as a catalyst. Then the liquefied woods (LWs) were characterized in terms of their suitability for PB production as a partial substitute for synthetic urea-formaldehyde (UF) resin. The standard properties of PBs such as tensile strength, bending strength and modulus of elasticity, density, moisture content, swelling after 24 h, water absorption, and formaldehyde content were measured. All tests were performed in comparison to a standard PB bonded by UF resin. It was demonstrated that the substitution of UF resin up to 20% of LW did not have a significant effect on the mechanical properties. PB made of recycled wood produced with LW possessed good mechanical properties that meet the European standard quality demands for PBs.

Crosslinking of Polyamide 6 by Reactive Processing

2015 ◽  
Vol 815 ◽  
pp. 576-582 ◽  
Author(s):  
Tao Yu ◽  
Jian Sheng Chen ◽  
Fu Mei Wu ◽  
Jens Rocks
Keyword(s):  
Polyamide 6 ◽  
Mechanical Tests ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Reactive Processing ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
Engineering Plastics ◽  
Chemical Coupling ◽  
Positive Effect

In order to check the feasibility of crosslinking engineering plastics through chemical coupling, reactive blending of polyamide 6 (PA6) was performed with various amounts of a multi-functional epoxide named as Joncryl ADR®4370s. The formation of cross-linked structure in ADR modified PA6 was clearly verified by utilizing dynamic rheological technique. The thermal properties of modified PA6 were compared with that of pristine nylon by combination of differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Mechanical tests were also carried out and the results showed that ADR had a positive effect on improving tensile properties of polyamide.

Novel phthalonitrile-based composites with excellent processing, thermal, and mechanical properties

2017 ◽  
Vol 30 (6) ◽  
pp. 720-730 ◽  
Author(s):  
Zuoqiang Wu ◽  
Shijie Wang ◽  
Lishuai Zong ◽  
Nan Li ◽  
Jinyan Wang ◽  
...  
Keyword(s):  
Glass Fiber ◽  
Bending Strength ◽  
Low Cost ◽  
Nitrogen Atmosphere ◽  
Gravimetric Analysis ◽  
Fiber Reinforced ◽  
Aryl Ether ◽  
Scanning Calorimetry ◽  
Aerospace Applications ◽  
Interlaminar Shear

Phthalonitrile resins exhibit excellent thermostability and mechanical strength after curing. However, poor processability made them difficult to fabricate fiber-reinforced composites with desirable integrated performance. In this article, a novel mixed phthalonitrile resin was developed to be used as the matrix for glass fiber–reinforced laminates. Poly (aryl ether nitrile phthalazinone) oligomer end-capped by phthalonitrile units (PPEN-PN) was firstly designed and blended with bisphenol-based phthalonitrile monomers (BP-PN) (Figure 1), which were obtained according to the literature procedure. A novel mixed curing agent (zinc chloride and 4,4-diamine-diphenylsulfone) was also exploited to accelerate curing rate of the resins. Solubility tests, differential scanning calorimetry and rheological studies revealed that the mixed resins exhibited good processability with low processing viscosity. Thermal gravimetric analysis indicated that the cured resins were stable below 530 to approximately 570 °C in nitrogen atmosphere after low-cost curing procedure. In air, char yields of the resins were between 30 to approximately 40% when heated to 800 °C. The laminates reinforced by E-glass fiber cloth possessed a bending strength of 668 MPa with interlaminar shear strength of 84.6 MPa at room temperature. 50% of the strength and modulus was maintained when heated to 400 °C. Consequently, this type of laminates may be potential candidates for aerospace applications.

Antioxidation Activity of Cysteine and Cystine Prepared from Sheep Wool

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. 

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

Holzforschung ◽  
2015 ◽  
Vol 69 (2) ◽  
pp. 199-205 ◽  
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.

Synthesis and Application of a Modifier with Low Formaldehyde Emission to Enhance General Wood Properties

2010 ◽  
Vol 129-131 ◽  
pp. 1018-1021 ◽  
Author(s):  
Yi Fei Jiang ◽  
Guo Feng Wu ◽  
Shu Ping Song ◽  
He Yu Chen ◽  
Jun Wen Pu
Keyword(s):  
Molecular Weight ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Treated Wood ◽  
Formaldehyde Emission ◽  
Degree Of Crystallinity ◽  
Low Molecular Weight ◽  
Impregnation Method ◽  
Pressing Method ◽  
Resin Impregnation

A preparation method of Urea-formaldehyde performed polymer(UFP) with low molecular weight and high reactivity is presented. The UFP can impregnate into wood along trachea from the ends with pressurized impregnation method. In the following heating and pressing processes of the wood, the UFP polymerizes, and it enhances stability and strength of the wood. The impregnating-pressing-drying method avoiding the disadvantage of dealing with the large specimens using vaccum-pressing method is suitable for industrial production. Results from test showed the degree of crystallinity tested by XRD were 30%, 32% in different dosage of the modifier. Utilizing a combination of low molecular weight resin impregnation and pressing resulted in a density increase of UFP treated wood from 0.214 to 0.268g/cm3. At the same time, the Young’s modulus and bending strength increased from 1.407GPa to 1.759GPa and 64MPa to 74.5MPa, respectively. But the formaldehyde emission is great reduced from 0.5% to 0.008%. It can be concluded that the effective utilization of UFP impregnated in wood is a promising technique for the production of high-strength in the drying and pressing processing.

Production of Ceramic Materials Using only Waste as Raw Materials

2015 ◽  
Vol 663 ◽  
pp. 62-71 ◽  
Author(s):  
R.J. Galán-Arboledas ◽  
Salvador Bueno
Keyword(s):  
Power Plant ◽  
Bending Strength ◽  
Raw Materials ◽  
Equilibrium Diagram ◽  
Thermo Gravimetric Analysis ◽  
Main Tool ◽  
Ceramic Materials ◽  
Absorption Capacity ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry

From a selection of inorganic industrial waste (screen glass, steelworks ashes, coal power plant ashes, biomass power plant ash and sludge from cutting marble industry) and a waste with organic fraction (diatomaceous earth from oil filtration) it is expected to obtain ceramic materials with properties similar to those of ceramic materials used in construction and porous materials with thermal insulating capability. The ternary phase equilibrium diagram SiO2-Al2O3-CaO has been used as the main tool for the formulation of these materials. The dynamic sintering study was carried out using dilatometry techniques (DIL), thermo gravimetric analysis and differential scanning calorimetry (TG-DSC). Characterization of the manufactured material allows determining a set of basic technological properties such as fired bulk density, water absorption capacity and bending strength, in addition to thermal conductivity and microstructure by SEM-EDX, in order to obtain the necessary data to determine technical feasibility.

scholarly journals Functionality of Beech Bark in Adhesive Mixtures Used in Plywood and Its Effect on the Stability Associated with Material Systems

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1298 ◽  
Author(s):  
Roman Réh ◽  
Rastislav Igaz ◽  
Ľuboš Krišťák ◽  
Ivan Ružiak ◽  
Milada Gajtanska ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Wood Processing ◽  
Material Systems ◽  
Adhesive Mixtures ◽  
The Common ◽  
The Stability ◽  
Heating Up

The results of research into utilizing grinded beech bark in order to substitute commonly used fillers in urea formaldehyde (UF) adhesive mixtures to bond plywood are presented in the present study. Four test groups of plywood with various adhesive mixtures were manufactured under laboratory conditions and used for experimentation. Plywood made using the same technology, with the common filler (technical flour), was used as a reference material. Three different concentrations of grinded beech bark were used. The thermal conductivity of the fillers used, viscosity and its time dependence, homogeneity and the dispersion performance of fillers were evaluated in the analysis of adhesive mixture. The time necessary for heating up the material during the pressing process was a further tested parameter. The produced plywood was analyzed in terms of its modulus of elasticity, bending strength, perpendicular tensile strength and free formaldehyde emissions. Following the research results, beech bark can be characterized as an ecologically friendly alternative to technical flour, shortening the time of pressing by up to 27%. At the same time, in terms of the statistics, the mechanical properties and stability of the material changed insignificantly, and the formaldehyde emissions reduced significantly, by up to 74%. The utilization of bark was in compliance with long-term sustainability, resulting in a decrease in the environmental impact of waste generated during the wood processing.

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

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1633 ◽  
Author(s):  
Venla Hemmilä ◽  
Stergios Adamopoulos ◽  
Reza Hosseinpourpia ◽  
Sheikh Ali Ahmed
Keyword(s):  
Furfuryl Alcohol ◽  
Urea Formaldehyde ◽  
Formaldehyde Emission ◽  
Raw Material ◽  
Curing Temperature ◽  
Modulus Of Rupture ◽  
Scanning Calorimetry ◽  
Material Source ◽  
Sustainable Materials ◽  
Emission Limits

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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