Urea-formaldehyde Adhesives Research Articles

Structure, properties and reaction mechanism of formaldehyde-free melamine-urea-glyoxal co-polycondensation resin

To reduce the harmful effects of free formaldehyde released from wood-based panel on human health and the environment, in this study, melamine-urea-glyoxal (MUG) resin was synthesized by using low-toxicity and biodegradable glyoxal instead of formaldehyde. It provides a comprehensive discussion on the structures, reaction mechanisms and properties of MUG resins with different molar ratios were compared and analyzed. FT-IR, 13C NMR, and XPS confirmed the co-polycondensation reaction between M, U, and G. However, with the change of raw material ratios, the structures of the MUG resins were less affected, the properties of the MUG resins were obviously different. When the molar ratio is R = n(M): n(U): n(G) = 0.16:0.30:1.0, thermal analysis showed that MUG plywood had better thermal stability. Evaluation of the gluing properties revealed that the dry and wet strengths of MUG adhesive bonded plywood reached 1.21 MPa and 0.91 MPa, respectively. In contrast to reported glyoxal-related wood adhesives, the MUG adhesive displayed much higher bonding strength, vastly superior water resistance. This study provides a new green pathway for the development of new urea formaldehyde adhesives, which helps to enhance their potential application value in the wood industry.

Effect of Resin Content on the Properties of Roofing Tile for Building Materials

The production process of roofing tile materials uses among other materials thermosetting adhesive resins normally urea formaldehyde (UF), phenol formaldehyde (PF), di-isocyanate (PMDI) at various content mixtures, 3wt%, 5wt%, 7wt%, 9w% and 11wt% with a usual thickness of 6 mm. The fibers, adhesives, and other materials are then placed into a steel mold with the standard dimensions of 400 mm x 400 mm, to be then hydraulically pressed at high pressure and the required temperature. Overall, PMDI synthetic adhesives have better physical and mechanical properties than PF synthetic adhesives, however the thermal properties of UF and PF synthetic adhesives are better than PMDI. The physical properties testing were density, humidity content, absorption of water, thickness inflated and water permeability. The mechanical properties such as modulus of rupture (MOR) and modulus of elasticity (MOE), impact strength and tensile strength are all measured according to JIS A 5908-2003, ASTM D 256-2006a,TIS 535-2556 and ASTM D1037-12.The testing for the thermal conductivity, thermal resistivity and solar reflectance were done according to ASTM C177-2010 and ASTM E 891-87. The type of resin content and adhesive used had a significant impact on the physical, mechanical and thermal properties of the roofing tile materials of showed in the results of the analysis of variance (p >0.05). The produced roofing tile has an improved thermal conductivity and heat insulation which can be a substitute for hazardous asbestos based roofing materials.

Bond line shear strength of structural wood adhesives at high temperatures up to wood carbonization – A classification approach

The European timber fire design code EN 1995-1-2 presently specifies that adhesives for timber construction products shall provide integrity throughout the intended fire exposure time, yet no test or requirement specifications are given. Contrary, in North America elevated temperature tests are mandatory and product standards for glued and cross laminated timber demand sufficient bond line shear strength up to 220 °C. This paper deals with block shear compression tests at ambient and elevated temperatures for development of a high temperature resistance classification system for structural wood adhesives. The investigations comprised 1200 specimens made from Norway spruce bonded with twelve brands from five adhesive families. Polycondensation (pcon) resins encompassed phenolic resorcinol formaldehyde, melamine urea formaldehyde and melamine formaldehyde adhesives. Polyaddition (padd) adhesives comprised five one-component polyurethanes and an emulsion polymer isocyanate. The focus was on the strength-temperature (fv-T) relationship of bonded and solid wood reference specimens at 180–270 °C. The pcon adhesives showed almost throughout a fv-T relationship close to solid wood up to 270 °C. Contrary, the padd adhesives revealed massive strength degradations vs. solid wood from 180 °C onwards. An adhesive test, evaluation and classification procedure with four classes T270 to T200 was derived. It is based on a comparison of the temperature-dependent shear strength decline in bonded samples vs. solid wood reference samples beyond 180 °C. Class T270 adhesives are proposed being suited for the linear charring model of EN 1995-1-2 as PRF adhesives without additional fire resistance testing of components deemed necessary today.

PRODUCTION OF PARTICLEBOARD PANELS FROM WOOD OF Ochroma pyramidale

The objective of this work was to evaluate the use of the species O. pyramidale for the production of particleboards. The trees, aged 6 years, came from the Municipality of Mira Estrela/SP state. The logs were peeled and processed in an industrial chopper to obtain particles. Eight treatments were carried out, varying the levels of paraffin emulsion (0, 1, 1.5 and 2%), and the levels of urea formaldehyde adhesives (10 and 12%). The particles went through a drying process until they reached 4% moisture. For pressing the panels, the parameters temperature of 160°C, specific pressure of 30 kgf/cm² and time of 10 minutes were used. The panels were tested by physical tests and mechanical tests, all following the procedures of the following standards: D-1037 (ASTM, 2006) for density, water determination and thickness increase and internal connection; DIN 52362 (1982) for parallel static bending. As a result, it was concluded that the increased addition of paraffin to the panels resulted in an improvement in their dimensional stability. The treatment that added 12% urea formaldehyde adhesive and 1.5% paraffin achieved superior results in mechanical properties, equivalent to 10390.91kgf cm-2 for the separation modulus, 101.46kgf cm-2 for the rupture modulus. The O. pyramidale particleboards reached the minimum values of 1.4 kgf/cm² for internal bonding and 56 kgf/cm² for the modulus of rupture required by CS 235-66 (1968), thus becoming a potential species for the production of particleboard panels.

Preparation and Characterization of Particleboard Made from Industrial-Type Wood Particles and Discarded Duck Feathers

Global poultry waste production is substantial, with billions of poultry raised annually for meat and egg production, resulting in significant feather waste. Conventional poultry waste disposal methods are restricted due to environmental concerns. Meanwhile, wood-composite panel industries face raw material shortages, emphasizing the need for sustainable, renewable fiber sources. In this study, in the core layer of panels, wood particles were replaced with 5 wt% clean duck feathers without pretreatment to take advantage of feather attributes like hydrophobicity, thermal insulation, and sound damping as an alternative construction material. Three adhesives—urea-formaldehyde (UF), polymeric 4,4′-diphenylmethane diisocyanate (pMDI), and polyvinyl acetate (PVAc)—were examined for resin–feather compatibility. The control panels in this study were identical but wood was not replaced with feathers. The results revealed that wood–feather particleboard with pMDI and PVAc resins meets the requirements of the relevant standard for P2 boards (where applicable) concerning their modulus of rupture (MOR: 11 N·mm−2), modulus of elasticity (MOE: 1600 N·mm−2), internal bond (IB: 0.35 N·mm−2), and screw withdrawal resistance (SWR). However, those produced with UF resin did not meet the standards for IB and MOE. Furthermore, the physical properties showed similar water resistance and thickness swelling to control panels with pMDI. Notably, substituting 5 wt% wood with feathers improved thermal insulation by approximately 10% for UF and pMDI resins. Additionally, particleboard with feathers demonstrated improved sound absorption at high frequencies, ranging from 2500 to 500 Hz, particularly with pMDI resin, approaching Class B classification according to EN ISO 11654:1997. This study identifies the higher compatibility of pMDI over PVAc and UF adhesives for feather-based composite materials in construction applications.

A formaldehyde-free amino resin alternative to urea-formaldehyde adhesives: A bio-based oxidized glucose – urea resin

Urea-formaldehyde resins (UF) are the most commonly used wood-based panels adhesive in industry. These adhesives are more than 80 % by volume of the wood adhesives market. However, due to formaldehyde toxicicity and extreme volatility UF resins yield panels with formaldehyde emission problem both during wood panels preparation and their in-service use. In order to address this problem, to find an environment friendly replacement for formaldehyde to manufacture novel and safe aminoresins is essential research for wood adhesives. In this article, a bio-based amino resin wood adhesive (OGU) is developed by using oxidized glucose reacted with urea. The research work presented here tests the impact on the adhesive properties of a number of oxidation treatment parameters and of the glucose to urea molar ratio. The molecular structure and thermal properties of the OGU adhesive were studied by different analytical techniques. The results indicate that the bioaldehydes are obtained by glucose under mild oxidation conditions. The bioaldehydes obtained can then be reacted with urea to form a novel oxidized glucose-urea amino resin, suitable to manufacture plywood. Under the specified process conditions at pH 4 and at a urea-to-glucose molar ratio of 1, the OGU adhesive yielded plywood with a dry strength of 0.99 MPa, 24 h cold water soaking wet strength of 0.77 MPa, and 3 h hot water (63°C) soaking wet strength of 0.76 MPa. These results satisfy the requirements of the GB/T 9846–2015 standard. The OGU resin adhesive prepared has then a good market potential to replace the current UF resins used in the industrial production of wood-based panels and as a novel biomass amino resin adhesive.

Influence of Pressing Temperatures on Physical-Mechanical Properties of Wood Particleboards Made with Urea-Formaldehyde Adhesive Containing Al2O3 and CuO Nanoparticles.

Particleboards have gained attention in the global market. Understanding their physical-mechanical behavior in the current technological context is essential due to adhesive polymerization, which depends on variables such as pressing time and temperature. Today, the use of nanoparticles has become a plausible option for improving the properties of polymers used in wood-based composites. This study evaluates the influences of the addition of non-commercial 0.5% aluminum oxide (Al2O3) and aluminum oxide copper (CuO) nanoparticles using a greener route with a lower environmental impact obtaining a urea-formaldehyde (UF)-based polymeric adhesive to manufacture particle composites of Eucalyptus urophylla var. grandis wood. Regarding characterizations, the resin properties analyzed were viscosity, gel time, and pH, as well as panel properties, including density, moisture content, thickness swelling, modulus of elasticity, modulus of rupture, and thermal conductivity. The results were compared with scientific publications and standards. The addition of nanoparticles interfered with viscosity, and all treatments indicated a basic pH. It was not possible to determine the gel time after 10 min. Nanoparticles added to the polymers in the internal layer did not cause an improvement in the swelling properties in terms of thickness, with no significant statistical difference for density and moisture content. The increase from 150 °C to 180 °C may have caused an improvement in all physical-mechanical properties, indicating that the higher temperature positively influenced the polymerization of the formaldehyde-based adhesive. Therefore, the additions of both nanoparticles (0.5% in each condition) led to a limitation in the material influence with respect to physical-mechanical performance.

The Removal of Formaldehyde from Urea Formaldehyde Adhesive by Sodium Borohydride Treatment and Its Application in Plywood.

The global production of plywood is constantly increasing as its application in the furniture and interior decoration industry becomes more widespread. An urgent issue is how to decrease the formaldehyde released from plywood, considering its carcinogenic effect on humans and harm to the environment. Reducing the free formaldehyde content of the urea formaldehyde (UF) adhesives used in the preparation process is considered an effective method. Therefore, it is necessary to identify a new type of formaldehyde scavengers. Here, the strongly reducing substance sodium borohydride was used to reduce and degrade the free formaldehyde in UF adhesives, and its effects on the properties of the UF adhesive and plywood were studied. When 0.7% sodium borohydride was added to the UF adhesive with a molar ratio of formaldehyde to urea of 1.4:1, the free formaldehyde content of the UF resin decreased to 0.21%, which is 53% lower than that of the untreated control. Moreover, the formaldehyde released from the plywood was reduced to 0.81 mg/L, ~45% lower than that from the group. The bonding strength of the treated samples could reach ~1.1 MPa, which was only reduced by ~4% compared to that of the control. This study of removing formaldehyde from UF adhesive by reduction could provide a new approach for suppressing formaldehyde release from the final products.

Molded Plywood with Proportions of Beech Bark in Adhesive Mixtures: Production on an Industrial Scale.

Molded plywood is used for furniture components such as seats, backrests, or integral seat shells, and it must be durable and harmless to health. Molded plywood is made with urea-formaldehyde (UF) adhesives; therefore, the issue of the fillers used in them is important. The potential of using ground beech (Fagus sylvatica L.) bark as an eco-friendly additive in UF adhesives for molded plywood manufacturing was investigated in this work. Wheat flour was used as a reference filler. The beech bark (BB) level as a filler was 10%, a value verified under laboratory conditions. Nine-layer flat and molded plywood were produced under industrial conditions from beech veneers bonded with a UF adhesive mixture. The mechanical (bending strength and bonding quality) and physical (swelling and absorbency values after 2 and 24 h) properties of the industrially fabricated molded plywood were evaluated and compared with the European standard requirements (EN 310 and EN 314-2). The mechanical properties of the molded plywood with the addition of BB in the adhesive mixture were acceptable and met these standards' requirements. The positive effect of BB in the UF adhesive mixture on a reduction in formaldehyde emissions from the molded plywood was also confirmed. BB, considered to be wood-processing industry waste or a by-product, has significant potential to be used as a filler in UF resins for molded plywood production, providing an environmentally friendly, inexpensive solution for the industrial valorization of bark as a bio-based formaldehyde scavenger.

Mechanical and Fire Properties of Flame-Retardant Laminated Bamboo Lumber Glued with Phenol Formaldehyde and Melamine Urea Formaldehyde Adhesives.

This study investigated the effects of different adhesives, phenol formaldehyde (PF) and melamine urea formaldehyde (MUF), on the mechanical and fire properties of flame-retardant laminated bamboo lumber (LBL). The results demonstrated that the flame-retardant treatment using phosphorus-nitrogen-boron compounds endowed the LBL with excellent flame retardancy and smoke suppression properties, even though the bending strength and bond shear strength were slightly reduced. The PF-glued LBL exhibited superior mechanical and shear properties to the MUF-glued ones, primarily due to its higher processing temperature and deeper adhesive penetration. In addition, the MUF-glued flame-retardant LBL displayed better heat release reduction and smoke suppression properties than the PF-glued LBL, which resulted from the synergistic flame retardancy between the melamine element in MUF and the applied flame retardant. The analysis of the influence of adhesive type on the mechanical and fire properties of flame-retardant LBL holds significant importance for the future design and production of high-performance LBL material.

The effects of wood fiber directions on bonding performance

Using engineered wood products (EWPs) in the building technologies is very crucial in terms of sustainable approaches. They provide; low weight, high structural stiffness, carbon storage capacity and easy erection on site. EWPs are composite materials that are influenced by a variety of factors that play a critical role in their formation. The chemical ingredients of the wood, the curing process of the adhesive, the type of wood, the relationship between the adhesive and the wood species, the curing temperature, the geometric configuration of the lamellae, etc. can all be included under the heading of these factors. In contrary with massive wood, to obtain EWPs different types of adhesives can be used. Therefore adhesive type and its application method affects the quality of wooden structural element. Choosing the appropriate adhesive is one of the steps to be taken to obtain the structurally correct product. Based on this approach, it was decided to investigate the adhesion performance of different adhesive types. This paper aims to present the best bonding method among the melamine urea formaldehyde (MUF) and epoxy adhesives by considering the fiber directions of the wood and the type of adhesive according to the load. One of the aims of this study is to investigate the effect of changing the fiber direction of wood on adhesion performance, taking into account the current gap in the literature. Pull-off tests were conducted to assess the bonding performance of different types of adhesive in wood samples with varying fiber direction. The wood samples were bonded to the wood surface with varying grain directions. During the pull-off tests, ruptures in the glue line of the test samples were commonly observed. The results have shown that in cylindrical samples bonded with epoxy, the highest bonding strength values were observed in scenarios where the wood fibers were oriented parallel to the load direction and perpendicular to the ground plane. Similarly, for wood samples used as the bonding surface, the highest bonding strength values were achieved when the wood fibers were oriented parallel to the load direction and perpendicular to the surface plane. On the other hand, the highest value in pull-off test setups was found with melamine urea formaldehyde adhesive; commonly used in laminated timber, between the wood samples with grains perpendicular to the load direction and the wood adherence surfaces with a parallel grain direction. In summary, the highest strength value was obtained from the test setup in which epoxy was used as the adhesive and both the wood specimens and the wood bonding surface had fiber directions parallel to the load direction.

Variation Of Bamboo and Adhesive Types on Physical And Mechanical Properties Of Particle Board

Bamboo can be used as a material in the manufacture of particleboard. The purpose of this study was to examine the effect of various types of bamboo and their adhesion on the physical and mechanical properties of particleboard. The study used a factorial completely randomized design with three repetitions. Particleboard made using cold pressing made of bamboo betung (Dendrocalamus asper Schult.), bamboo apus (Gigantochloa apus Kurz), bamboo ori (Bambusa arundinacea Retz), and Urea Formaldehyde and Polyvinyl Acetate adhesives. The particle size used was through eight meshes with an adhesive concentration of 20% and a target board density of 1 gram/cm³. Board testing using SNI 03-2105-2006, correlation analysis, and regression to see the relationship between variables. The resulting particleboard has a density between 0.5 – 0.69 gram/cm³, air content between 12.7% - 15.2%, thickness expansion between 2.2% - 17.55%, MOE 1.963 - 4.898 kg/ cm², MOR 4.89 – 9.36 kg/cm². The type of bamboo has no significant effect on density, moisture content, MOE, and MOR of particleboard. The type of adhesive has a significant effect on the density, MOE, and MOR of the particleboard. The interaction between the type of bamboo and the type of adhesive has a significant effect on the thickness development of the particleboard.

A synergistic enhancement of the bonding performance of urea-formaldehyde adhesives using an organic-inorganic hybrid strategy

A synergistic enhancement of the bonding performance of urea-formaldehyde adhesives using an organic-inorganic hybrid strategy

Thermal degradation and curing kinetic study of urea formaldehyde/l-tyrosine composites

In this study, the prepolymers (TYF) were prepared by formaldehyde and l-tyrosine, different amounts of TYF were added to prepare TYF modified urea-formaldehyde adhesives (LUF), and the gel time of resin, formaldehyde emission and wet shear strength of the plywood were tested. This result indicated that the optimal addition amount was 3 wt%, and the formaldehyde emission of plywood decreased by 23% to 0.57 mg/L, and the wet shear strength increased by 47% to 1.47 MPa. The thermal degradation and curing characteristics of urea-formaldehyde (UF) and LUF resins were characterized by thermogravimetric (TG) and differential scanning calorimetry (DSC), and the kinetic parameters were analyzed. The results showed that TYF could reduce the formaldehyde emission and improve the wet shear strength significantly. Moreover, the thermal degradation activation energy (Eα) of UF resin was increased, and the thermal stability was enhanced. Although the initial and peak curing temperatures of LUF were higher, but the LUF cured more easily than the UF once the curing temperature was reached.

Analysis and Impact of Activated Carbon Incorporation into Urea-Formaldehyde Adhesive on the Properties of Particleboard

Nowadays, the particleboard industry cannot meet the market’s demand. Therefore, filler materials have started to be used both to conserve raw materials and to enable the use of wood-based boards in different areas. This study investigates the effects of incorporating different ratios of activated carbon (0%, 1.5%, 4.5%, 7.5%) on the properties of particleboards. The physical properties were examined, including density, moisture content, thickness swelling, and water absorption. The results reveal that the density increased with increasing activated carbon content while the moisture content decreased, indicating improved dimensional stability and water resistance. Additionally, the color properties were influenced by activated carbon, leading to a darker appearance with decreased lightness and yellow-blue components. The mechanical properties, such as internal bond strength, modulus of rupture, and modulus of elasticity, showed significant enhancements with the addition of activated carbon, indicating improved bonding and increased strength. Moreover, the thermal conductivity decreased with increasing activated carbon content and improved insulation performance. Scanning electron microscope analysis confirmed the uniform distribution of activated carbon within the particleboard matrix, without agglomeration, positively impacting the mechanical performance. According to the thermogravimetric analysis results, the addition of activated carbon led to a decrease of up to 6.15% in mass loss compared to the control group. The incorporation of activated carbon at a ratio of 4.5% in particleboards confers notable enhancement to their physical, mechanical, and thermal characteristics. These findings contribute to understanding the potential benefits and considerations of using activated carbon as an additive in particleboard production.

Determination of the effect of valonia tannin when used as a filler on the formaldehyde emission and adhesion properties of plywood with artificial neural network analysis

Although artificial neural networks (ANN) have been used frequently in engineering applications, it has been determined that they are not preferred much, especially in determining adhesive properties and usage. Hence, this study aimed to determine the effect of urea formaldehyde (UF) resin mixed with valonia tannin obtained from Turkish oak acorns (Quercus aegilops) as a filler on the formaldehyde emission and bonding strength of plywood panels by using ANN modelling. For this purpose, six different valonia tannin contents and three different adhesive usages were chosen, and they were compared to control panels. The formaldehyde emission and bonding strength experimental data obtained according to relevant standards were analysed by using ANN. The prediction models with the best performance and acceptable deviations were determined using statistical and graphical comparisons between the experimental data and the prediction values obtained from the ANN analysis. Using these prediction models, the formaldehyde emission and bonding strength data were obtained according to the amount of valonia tannin and adhesive usage not used in the experimental study. Experimental results have proved that valonia tannin obtained from Turkish oak acorns is a good formaldehyde scavenger for UF adhesives, but it has been determined that it has a negative effect on the bonding strength of plywood. As a result of the ANN analysis, the lowest formaldehyde emission values were obtained from 12% to 15% valonia tannin and 140 g/m2 - 146 g/m2 adhesive usage. The bonding strength values of all the predicted plywood groups exceeded the limit value of the relevant standard except for the 5% valonia tannin and 140 g/m2 - 158 g/m2 adhesive usage.

Use of Dynamic Shear Rheology to Understand Soy Protein Dispersion Properties.

Soy flour dispersions are used as adhesives for bonding interior wood laminates, but the high viscosity of these dispersions requires low solids in the adhesive formulations; the greater water content causes excessive steam pressure during hot press manufacturing. This limits the utility of soy adhesives in replacing urea-formaldehyde adhesives; thus, understanding the cause of high soy viscosities is important. Lack of literature on aqueous soy flour dispersion rheology led to our dynamic rheology studies of these dispersions to understand high viscosity and the effect of various additives. Even at low soy solids, the elastic nature outweighs the viscous properties at low shear, although increasing the shear results in shear-thinning behavior after the yield point. At even higher shear, beyond the flow point where the storage and loss moduli cross, some of the dispersions show an additional shear thinning transition. The comparison of the rheological properties of aqueous dispersions of the soy flour and protein isolate, and another natural protein, ovalbumin from egg whites, led to a better understanding of different types of rheological behaviors. The experimental observations of two observed shear thinning events for soy are consistent with the model of dispersed particles, forming clusters that then form large scale flocculants.

Теоретическое и экспериментальное обоснование характера взаимодействия модифицированных связующих с древесиной

There are numerous methods for analyzing surface phenomena when bonding wood materials, mutual arrangement of pores in the wood substrate, and depth of liquid adhesive penetration into wood. Electron microscopic methods such as atomic force and scanning tunneling microscopy are used along with optical methods. They allow evaluating the influence of factors describing the interaction between the liquid adhesive molecules and the porous wood surface. Phenol formaldehyde resin modified with pectol and urea formaldehyde resin modified with lignosulfonates were used for substantiation of the interaction mechanism between modified adhesives and wood. Electron microscopy was used to study the depth of adhesive penetration into veneer. The plywood was produced using modified urea and phenol formaldehyde adhesives. After conditioning, samples with a thickness of 0.025 mm were cut out and examined with a scanning electron microscope. The article shows that the interaction between liquid phenol formaldehyde adhesive modified with pectol and wood results in a sequential increase in the molecular weight of the substances and, consequently, in the penetration degree (depth). The studied wood species (birch, pine and larch) and modified thermosetting urea and phenol formaldehyde adhesives are polar materials (adhesive interacts with wood molecules with the formation of intermolecular bonds, including hydrogen bonds). The molecular weight growth and the freely joined nature of the main chain (liquid modified adhesive macromolecules), which contains a large number of polar functional groups (adhesive and wood), promote intermolecular association. The formation of an adhesive bond between urea formaldehyde adhesive modified with lignosulfonates and wood occurs due to chemical interaction between hydroxyl groups of cellulose macromolecules and methoxyl groups of urea resin with the formation of esters (hydrogen atoms of hydroxyl groups OH are substituted with hydrocarbon radicals R). The formation of a bond between the adhesive and the wood surface is the result of molecular interaction forces at the liquid adhesive – wood interface, when the distance between molecules of the same polarity (adhesive and wood) is less than 0.5 nm. Then, adsorption equilibrium sets in. For citation: Rusakov D.S., Varankina G.S., Chubinsky A.N. Theoretical and Experimental Substantiation of the Nature of Interaction between Modified Binders and Wood. Lesnoy Zhurnal = Russian Forestry Journal, 2022, no. 6, pp. 153–163. (In Russ.). https://doi.org/10.37482/0536-1036-2022-6-153-163

Use of Thymus Plants as an Ecological Filler in Urea-Formaldehyde Adhesives Intended for Bonding Plywood

Innovative adhesive formulations have been developed in the laboratory based on urea-formaldehyde resin by adding medicinal plants to an industrial adhesive formulation containing raw materials: urea-formaldehyde resin, urea, ammonium sulphate and starch. Specifically, Thymus species (Thymus bleicherianus, Thymus capitates, Thymus satureioides, Thymus vulgaris and Thymus zygis) replaced part of the starch and were considered as the second filler in the formulations. The physico-chemical properties of the resulting adhesive formulations, such as: pH, viscosity, gel time, solids content, density, concentration of free formaldehyde and color were measured, and characterized using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared spectroscopy (FTIR). In order to evaluate the mechanical performances of adhesive formulations based on plants, plywood panels were produced and their mechanical properties were studied. These mechanical properties included the shear strength, bending strength and the modulus of elasticity. The performance of these panels is comparable to that of plywood panels made using the standard adhesive formulation. From the results obtained, and following the statistical studies, the new adhesive formulations based on plants have the same physico-chemical properties, the same morphologies, and the same mechanical properties. Moreover, the novel adhesives are more viscous, and they have less free formaldehyde content than the commercial formulation.

Sifat Fisika dan Mekanika Papan Partikel Berbahan Limbah Industri PT. Aldi Mandomai Mebel

This research aims to determine the effect of particle sizes (10 mesh, 20 mesh, and 30 mesh) on the physical and mechanical properties of particleboards made from industry waste of PT. Aldi Mandomai Furniture, based on JIS A 5903: 2003 Standard. . Particleboards size were 30 x30x1,5 cm, density 0,5 g/cm3. Moisture content particles at 5%, particles glued with urea-formaldehyde adhesives, weight 10%, hot press pressured with temperature 110 ± 20C for 15 minutes, pressure 25 kg/ cm2. Furthermore, particleboards must be conditioned for ± 14 days/ 2 weeks. Particleboards were cut into sample test according to the size in the JIS A 5903:2003 standard. Research design used Completely Random Design with one factor. Data analyzed using analysis of variance, if data was significant must to do areal difference test. The observed to particle size with 3 levels are 10 mesh, 20 mesh, and 30 mesh. The results of physical properties were Density ( a.v. 0,46 – 0,49 g/cm³), Moisture Content (a.v. 12,22 – 14,05%), Water Absorption (a.v 129,79 – 167,03%), and Thickness Swelling (a.v 11,43 – 22,08%). The results of mechanical properties were internal bonding (0,0075 - 0,0204 N/mm2), Modulus of Elasticity (a.v. 5,91 – 25,32 N/mm2), Modulus of Rupture (a.v 0,52 – 1,52 N/mm2 ), and Screw Holding (a.v. 29,42 – 104,60 N). Particleboards made from furniture industry waste with particle size 10 mesh was significantly to physical properties, except density and fulfill JIS A 5903:2003, while the mechanical properties of particleboard are not fulfill the standard.