Polyurethane Glue Research Articles

Evaluation of the Applicability of Waste Rubber in Insulation Panels with Regard to Its Grain Size and Panel Thickness.

This paper explores the effect of waste rubber grain size on the porosity, modulus of elasticity, thermal properties, and soundproofing performance of polymer composites with different thicknesses (10, 15, and 20 mm). All properties were tested in accordance with European standards, with the exception of porosity, which was measured using Archimedes' principle. The findings indicate that with a consistent amount of polyurethane glue, finer rubber grains result in composites with higher porosity, leading to a lower modulus of elasticity but enhanced thermal and sound insulation. In contrast, coarser rubber grains produced composites with lower porosity and a higher modulus of elasticity, though with slightly reduced thermal insulation and significantly worse soundproofing. A combination of fine and coarse rubber grains provided a balanced performance, offering both good thermal and sound insulation while maintaining a high modulus of elasticity. Among the thicknesses tested, 15 mm was identified as optimal, combining a relatively high modulus of elasticity, low thermal conductivity, and better airborne sound insulation index. Future research will focus on applying this composite in concrete building products that meet noise protection and energy efficiency standards.

THE EFFECT OF SUPPORT LAYER MATERIAL AND ADHESIVE TYPE ON COMPRESSIVE DYNAMIC BENDING AND SHEAR STRENGTH IN LAMINATED WOOD

In this study, strength properties of wood material reinforced with carbon fiber fabric, steel wire mesh and bamboo veneer were determined. Polyvinylacetate (PVAc) and polyurethane (PUR) glues (D4)were used for the lamellas obtained from Scotch pine (Pinus sylvestris L.) and eastern beech (Fagus orientalis L.). Compressive strength according to TS EN 408+A1; dynamic bending (shock) strength according toTS ISO 13061-10 and shear strength according to ASTM D 3110 were determined on 3 and 5-layers samples. According to the results, the highest compressive strength (62.8 N/mm2) was found in 5-layerseastern beech samples reinforced with carbon fiber fabric and bonded with PUR glue. The highest dynamic bending strength value (110.8 kJ/m2) was found in 5-layerseastern beech samples reinforced with carbon fiber fabric and bonded with PUR glue and the highest shear strength value (12.3 N/mm2) in 3-layered eastern beech samples reinforced with steel wire mesh and bonded with PUR glue.

Test of three-storey confined masonry structure built from clay blocks and PU glue

The paper presents an experimental test of a nearly full-scale three-storey model of a confined masonry structure. The walls were constructed using newly developed clay masonry blocks, with large holes filled with thermal insulation and polyurethane glue instead of mortar. In the construction,relatively thick 38 cm walls and large tie-columns with 25 cm × 25 cm plan dimensions. The test model was built as confined masonry according to Eurocode 8. The innovative materials and construction were developed for thermal efficiency and the test was intended to verify the structural response. The model, test setup, and test procedures are described, and the results of the tests are analysed. The building responded primarily in shear, and ultimately failed in the ground floor in a storey mechanism, but there was also substantial damage on the floor above. Due to the non-standard dimensions of the tie-columns and because masonry was thicker than the tie-columns, the in-plane loaded walls developed an interesting response mechanism in which protruding masonry sheared off. Although this did not significantly impact the overall response, it led to the earlier onset of the significant damage limit state of the structure. The model responded well with wide hysteretic loops and distributed damage, which indicated large energy dissipation capacity, and the response envelopes showed gradual strength deterioration after peak load. The response of the model was quantitatively estimated using the N2 method. Calculations showed that the tested model could withstand a design seismic load corresponding to a 0.21 g peak ground acceleration with significant damage and almost 0.52 g before collapsing. The overstrength was estimated at 1.71.

Study of the thermal protection characteristics of composite aerated concrete lintels when optimizing the life cycle of a building

The article is devoted to the study of the effectiveness of various methods of reinforcing composite aerated concrete lintels intended for window and door openings in the construction of civil buildings. The authors have developed a composite aerated concrete lintel for window and door openings, which includes two or three aerated concrete blocks and a seam at the ends made with polyurethane glue. The lintel reinforcement is made in the form of tape and parts of carbon fiber tape attached to aerated concrete blocks. The article provides a comparative analysis of various methods of reinforcing lintels made of aerated concrete, including steel rods and glass-composite reinforcement, as well as external tape reinforcement using carbon tapes. The results of the study allow us to conclude that external tape reinforcement with carbon fiber tapes is the most effective method. The most thermally efficient type of lintel reinforcement is external tape reinforcement with carbon fiber tapes, since the reduced heat transfer resistance is 6-10% higher than that of similar lintels with another type of reinforcement, and 10-28% higher than traditionally used lintels (reinforced solid lintels and composite U-shaped lintels).

Research of Insertion Loss of Multilayered Construction with Devulcanized Waste Rubber

Abstract In this study, the insertion loss of devulcanized waste rubber baffles were evaluated. Acoustic baffles are suitable to reduce noise from the devices or machines by interfering with their emitting sound waves. Knowledge of the acoustic properties of the material used is of significant importance in ensuring the effectiveness of the acoustic properties of the baffle. Basic properties include airborne sound insulation, which is usually determined during laboratory tests. Baffles consists of sound absorbing and sound insulating materials. In this study, plasterboards were used as sound insulating material and devulcanized waste rubber as sound absorbing material. During the devulcanization process, porous granules are obtained, which can be used as an acoustic material. In this study, two types of rubber granules were devulcanized by grinding method and one other type was chemically devulcanized. Three types of rubber granules were mixed together in increasing 25 % proportion steps and glued with patented polyurethane glue. A total of 15 different composition devulcanized waste rubber granule boards were made. Rubber boards were attached together with the plasterboards. Insertion loss of the different composite baffles was measured in semi-anechoic chamber in a purposefully designed stand in 1/3rd octave bands. The results showed that the insertion loss of the baffles was mostly dependent on the rubber granule board density. When the density of the rubber board increased, the insertion loss also increased. The 5–6 dB insertion loss difference was measured between the most and least dense rubber granule board baffles.

In-plane seismic behaviour of urm and confined masonry built from vertically perforated blocks and polyurethane glue

Masonry construction using vertically perforated clay blocks with large holes and polyurethane glue is a modern technology designed primarily for low thermal losses. This study aims to evaluate the in-plane seismic behaviour of masonry constructed using unreinforced masonry (URM) and confined masonry construction technology. The experimental methods consist of triplet tests on joints and cyclic shear compression tests on eight full-scale walls, six of which are URM and two of which are confined masonry. Tests on URM walls are performed at three different levels of compressive stress to analyse the effect of compressive stress on the seismic response. The effects of compressive stress on shear resistance and drift capacity are quantified and compared with results from a database. The performance of the tested walls is comparable to what is expected from modern URM walls. Two confined masonry walls were of the same dimensions as the URM walls and are evaluated at the highest compressive stress level used in tests of URM walls. The results indicate that confined masonry should be the preferred technology for seismic regions because of its higher strength, displacement capacity, ductility, and energy dissipation.

Influence of a mortar type on shrinkage of autoclaved aerated concrete

AbstractShrinkage is one of the most important properties of Autoclaved Aerated Concrete (AAC), which is tested in accordance with EN 680:2008. Unfortunately, in construction, we have only a situation where AAC blocks are connected together with different types of mortar: standard mortar, thin joint mortar, or polyurethane glue. The shrinkage of masonry structures is determined by properties of AAC and properties of the used glue system. This research program, based on the standard EN 680, included AAC specimens of different density classes connected with various types of mortar: thin joint mortar with different compressive strengths, manufactured by various producers, and polyurethane glue. Specimens were prepared in accordance with the standard EN 680:2008, but connected by mortars in two different directions. Test results can be helpful in designing masonry structures.

Sound Insertion Loss Performance of Baffles with Devulcanized Waste Rubber

In this study, the insertion loss of devulcanized waste rubber baffles was evaluated. Acoustic baffles are suitable for reducing noise from the devices or machines by interfering with their emitting sound waves. Knowledge of the acoustic properties of the material used is of significant importance in ensuring the effectiveness of the acoustic properties of the baffle. Basic properties include airborne sound insulation, which is usually determined during laboratory testing. Baffle consists of sound absorbing and sound insulating materials. In this study, plasterboards were used as sound insulating material and devulcanized waste rubber as sound absorbing material. Devulcanization targets mostly the scission of sulphur crosslinks. Devulcanization techniques that have been explored in rubber recycling include thermos-chemical, microbiological, ultrasonic microwave thermos-chemical devulcanization in a supercritical carbon dioxide medium (scCO2). In this study, two types of rubber granules were devulcanized by grinding method and one other type was chemically devulcanized. Three types of rubber granules were mixed together in increasing 25 % proportion steps and glued with patented polyurethane glue. Total of 15 different composition devulcanized waste rubber granule boards were made. Rubber boards were attached together with the plasterboards. Insertion loss of the different composite baffles was measured in semi-anechoic chamber in a purposefully designed stand in 1/3rd-octave bands. The results showed that the insertion loss of the baffles depends mostly on the rubber granule board density. Increasing the density of the rubber board, insertion loss also increased. 5–6 dB insertion loss difference was measured between the most and the least dense rubber granule board baffles.

Thermal, Acoustic, and Hygrothermal Properties of Recycled Bovine Leather Cutting Waste-Based Panels with Different Compositions

This study aims to investigate the thermo-acoustic and hygrothermal properties of innovative panels made of leather waste produced by a bag factory from a circular economy perspective. Their performance was compared with other residual-based insulation panels. The leather scraps were chipped and three boards were fabricated by means of a mold with different compositions, adding adhesive glue. In order to improve the sustainability aspects, a sample was assembled by using a water-based polyurethane glue, in addition to the two panels with vinyl glue. Panels were tested for thermal, acoustic, and hygrothermal performance. Thermal conductivity values in the range of 0.064–0.078 W/mK at 10 °C were measured depending on the composition and the adhesive. A slight thermal performance deterioration occurs when using the natural water-based glue. The samples were characterized by good performance both in terms of sound absorption coefficient (Noise Reduction Coefficient NRC = 0.21–0.28) and Transmission Loss, up to 59 dB values. Water vapor resistance factor values in the 35–48 range were obtained, close to the values of standard materials, such as expanded polystyrene and polyurethane.

The effect of polyurethane foam glue on the strength and deformability of aerated concrete masonry when using it as a masonry mortar

The article presents the results of experimental studies of masonry made of cellular concrete blocks of autoclave hardening YTONG produced by JSC «Kcell-Aeroblock-Center» on the adhesive composition (polyurethane glue) Dryfix (POLYPAG AG). The tests included comprehensive studies of the strength and deformability of masonry walls made of cellular concrete blocks, under various types of stress state of structures: central and off-center compression of masonry walls, axial tension on bandaged and unbound seams, tensile bending on bandaged and unbound seams, shear with an assessment of tangential adhesion. Tests have confirmed the inconsistency of the technology of laying blocks of cellular concrete on the adhesive composition of Dryfix with incomplete filling of seams. This technology has a significant impact on the strength of the masonry during bending: the adhesion of the blocks to each other with such an adhesive composition applied to the surface of the block is significantly lower than the value obtained when testing the blocks for axial tension. According to the results of the experiments, the value of the temporary resistance to axial stretching along the unbound section (normal adhesion) of the masonry, the values of the calculated resistance of the masonry to stretching during bending along the unbound and tied sections, as well as the value of the calculated resistance of the masonry under central compression were determined.

Effect of Primary Spruce Lamella Aging on the Bending Characteristics of Glulam Beams

Glued laminated (glulam) beams are used in the roofs, ceilings and walls of buildings as well as in bridges and towers. At present, with the limitation of tree harvesting, the production of glulam beams from recycled wood sources is implemented with the proviso that their mechanical properties and resistance to pests, fire and weathering will not be aggravated. This work deals with the primary effect of aging Norway spruce wood (Picea abies Karst. L.) lamellas on the moduli of rupture (MOR) and elasticity (MOE) in bending of three-layer glulam beams composed of sound and aged lamellas and polyurethane (PUR) glue. Three methods of lamella aging were used: (A) natural, lasting 60 years in the form of roof trusses with a greater or lesser degree of bio-attack by woodworm (Anobium punctatum De Geer); (B) artificial, caused by increased temperatures from 160 to 220 °C for 4 h; (C) artificial, caused by 2% water solutions of inorganic preservatives, namely, CuSO4 × 5H2O, ZnCl2, H3BO3 or (NH4)2SO4, for 28 days. The lowest MOR values were determined for glulam beams in which all three lamellas or two surface lamellas had a greater degree of bio-attack (60.5 MPa, a decrease of 25.9%) or were exposed to primary aging at 220 °C (62.6 MPa, a decrease of 23.3%). On the contrary, the exposure of lamellas to 160 or 180 °C did not significantly influence the MOR of beams (76.0–82.7 MPa, an average decrease of 1.6%). The MOE of glulam beams ranged from 7540 to 10,432 MPa without an obvious influence of the method of lamella aging or their location in the beams. Linear correlations between the MOR or MOE of glulam beams and the shear strength (σ) of glued joints, if both composite types consisted of similarly aged lamellas, were only slightly significant or insignificant.

SEM Analysis of Glued Joints of Thermally Modified Wood Bonded with PUR and PVAc Glues.

This study deals with the scanning electron microscopy (SEM) analyses of the phase interfaces in the glued joints between Norway spruce wood elements thermally modified at 160, 180, 200, and 220 °C/4 h and polyurethane (PUR) and polyvinyl acetate (PVAc) glues with the aim of evaluating various anatomical influences of wood on the quality of joints. Due to cracked regions created in the surface of spruce wood at severe thermal modifications, the penetration depth of glues doubled from 140 to 241 μm for PUR glue, and from 100 to 200 μm for PVAc glue. The thickness of glue lines in joints was apparently higher for PVAc glue, mainly in earlywood regions; however, in joints from thermally modified (TM) woods it increased more apparently for PUR glue from 16.6 to 44.4 μm, probably in connection with formation of micro-bubbles in its structure. The SEM analyses corresponded well with the previous knowledge about lower shear strength of glued joints formed from the more intensively TM spruce elements and mentioned types of glues.

Force and Slip Displacement of Fibre Cemboard Panels Subjected To Four-Point Bending Test

For many years, fibre cemboard has been widely used in the construction industry. This material has many advantages, including a long-life span, ease of installation and low maintenance, which can reduce the cost of maintenance. However, due to its limitation of being unable to support heavy loads, it is only suitable for the lightweight floor system. Therefore, the fibre cemboard panel is introduced. Basically, the fibre cemboard panel consists of several layers of fibre cemboard that stack together using a special bond mechanism. This study aims to investigate the flexural capacity and slip displacement of fibre cemboard panels with different bond mechanisms (polyurethane glue, steel bolts and polyurethane glue + steel bolts) and spacings (50 mm, 75 mm, 100 mm, 150 mm, and 200 mm). The specimens were fabricated with a size of 305 mm width, 1220 mm span and 2@16 thickness. The four-point bending test was carried out using Universal Testing Machine (UTM) that yield the force-slip displacement curves.The results of experimental testing indicate that the bond mechanism has an apparent impact on the flexural capacity and slip displacement. The fibre cemboard panels bonded by steel bolts have the best performance. Meanwhile, the spacing was found to control the slip displacement the most than the flexural capacity. Close distance of spacing may increase the stiffness that appreciably contributes to better performance. The optimum spacing for the polyurethane glue is 50 mm, while the specimens bonded by steel bolts and polyurethane glue + steel bolts should have 75 mm and100 mm spacings. The polyurethane glue can hold the stress concentration before the detachment. When polyurethane glue fails, the steel bolts resume the function to resist the slip displacement until the rapture.

Diatomaceous earth foliar spraying along with adjuvants in pistachio orchards associated with the common pistachio psylla, Agonoscena pistaciae.

The common pistachio psylla, Agonoscena pistaciae, is a serious global pest menacing pistachio orchards. Considering the dangers of using excessive chemical pesticides, it seems that using natural insecticides such as diatomaceous earth is a suitable way to lower the residual amount of highly hazardous pesticides. In this study, the effects of diatomaceous earth with different additives, including dipotassium hydrogen phosphate, polyurethane glue as a wood adhesive, and potassium silicate, were investigated in several concentrations over two years in orchard conditions. Although all treatments showed significant effects, the most effective treatments were (diatomaceous earth+dipotassium hydrogen phosphate) and (diatomaceous earth+polyurethane glue). Therefore, the use of diatomaceous earth combined with the additive materials mentioned can potentially be a safe method for the integrated management of the common pistachio psylla.

Universal Preparation Strategy for Ultradurable Antibacterial Fabrics through Coating an Adhesive Nanosilver Glue.

Microbiological protection textile materials played an important role in the battle against the epidemic. However, the traditional active antimicrobial treatment of textiles suffers from narrow textile applicability, low chemical stability, and poor washability. Here, a high-strength adhesive nanosilver glue was synthesized by introducing nontoxic water-soluble polyurethane glue as a protectant. The as-prepared nanosilver glue could adhere firmly to the fiber surfaces by forming a flexible polymer film and could encapsulate nanosilver inside the glue. The as-prepared nanosilver had a torispherical structure with diameter of ~22 nm, zeta potential of −42.7 mV, and good dispersibility in water, and it could be stored for one year. Further studies indicated that the nanosilver glue had wide applicability to the main fabric species, such as cotton and polyester fabric, surgical mask, latex paint, and wood paint. The antimicrobial cotton and polyester fabrics were prepared by a simple impregnation–padding–baking process. The corresponding antimicrobial activity was positively correlated with nanosilver content. The treated fabrics (500 mg/kg) exhibited ultrahigh washing resistance (maintained over 99% antibacterial rates for 100 times of standard washing) and wear resistance (99% antibacterial rates for 8000 times of standard wearing), equivalent breathability to untreated fabric, improved mechanical properties, and good flexibility, demonstrating a potential in cleanable and reusable microbiological protection textiles.

The Effect of Inorganic Preservatives in the Norway Spruce Wood on Its Wettability and Adhesion with PUR Glue

Recycled recovered wood, for example, from historic buildings, containing biocides, fire retardants or anti-weather paints is an attractive material for manufacturing composite wood panels which can be used for decoration as well as load-bearing walls with a typical patina. This paper investigates the effect of four inorganic wood preservatives—CuSO4·5H2O, ZnCl2, H3BO3 and (NH4)2SO4—commonly used in the past, with the focus on their effect on the quality of wood bonding. The milled surfaces of Norway spruce (Picea abies Karst L.) wood were treated with 0.5, 1 and 2% aqueous solutions of these preservatives. The effect of preservatives in spruce wood was evaluated: (1) by its wettability with the drops of redistilled water, measuring the contact angles; (2) by the shear strength of the “spruce wood—polyurethane (PUR) Kestopur 1030 glue” interphases according to the standard EN 205; (3) by microscopic analysis of the “wood—PUR” interphases. The wettability of spruce wood worsened when using ZnCl2, by a maximum of 28.2%, but on the contrary, it improved due to other preservatives mainly by using (NH4)2SO4, at a maximum of 22.9%. In general, the shear strength of glued joints “wood—PUR” continually decreased with higher concentrations of all the preservatives. The most significant decrease of adhesion “wood—PUR”, by 19.8% from 10.66 MPa to 8.55 MPa, was caused by 2% ZnCl2 used for the treatment of both spruce wood specimens in interphase with the PUR glue. On the contrary, the less significant decrease of adhesion “wood—PUR”, by 2.5%, was caused by 0.5% (NH4)2SO4 applied only on one surface of the two inter-bonded spruce wood specimens. The effects of preservatives on the wood wettability and its adhesion with PUR glue were partly confirmed by microscopic analysis.

Повышение теплотехнической однородности стен из ячеистобетонных блоков

The development of effective protecting structures is currently one of the most popular areas in the construction industry. Masonry made of aerated concrete blocks is used in conditions of ensuring energy efficiency and environmental safety in the construction of civil buildings as enclosing structures. It has high thermal protection properties. The issue of filling through seams of aerated concrete masonry is acute, since adhesive and cement-sand mortars in masonry have low thermal conductivity and are temperature bridges. The authors have developed a two-row energy-efficient wall masonry made of aerated concrete blocks using polyurethane glue as a filler for through and dressing joints. The article discusses the effect of horizontal through joints made of cement-sand mortar and blocking of blocks on the resistance to heat transfer of masonry from aerated concrete blocks. In addition, it presents a study of the reduced resistance to heat transfer of the enclosing structure, taking into account heat-conducting inclusions, presented in the form of a traditional two-row aerated concrete masonry through a row, made on a thin-layer adhesive solution, as well as the masonry developed by the authors. It is concluded that the energy efficiency of the developed wall fencing is ensured due to the increased thermal homogeneity of the masonry.

Experimental Analysis on the Curing and Adhesive Behaviour of Standard Moisture-cured and Fast-cured Polyurethanes Used in Automotive Industry

In this paper, the adhesive behaviour of different polyurethane glues was studied and compared. The study was inspired by real conditions in the production of car windows, and it is divided into several parts, which deal with three types of polyurethane adhesives. The first type is a standard one-component polyurethane adhesive, which cures with air humidity. The second type is a one-component polyurethane adhesive with the addition of a curing accelerator. And the third type is a two-component polyurethane adhesive. Adhesive blocks of defined dimensions and plastic parts glued to the glass were used for this experiment to simulate a real product. The influence of temperature and humidity on the curing process was evaluated. The test included measuring the force required to tear the parts from the glass and assessing the type of failure. Based on the achieved results, the adhesives were evaluated regarding their applicability in the real automotive industry and the key properties necessary to maintain the safety and quality of the glued part were determined

Influence of the glue joint on the speed of propagation of sound waves in wood

Influence of the glue joint on the speed of propagation of sound waves in wood. The aim of this study is to demonstrate differences in the propagation of sound waves in wood depending on the type of glue used to form the joint. Samples of tree species considered as resonant wood, i.e. Norway spruce (Picea abies) and sycamore (Acer pseudoplatanus), and for comparison, wood of European beech (Fagus sylvatica) were used. The fractured samples were glued together using glutinous fish glue, polyurethane glue (Titebond Liquid Glue) and cyanoacrylate glue (BONDOLOC B415). All types of glue are used in instrument repair, of which glutinous glue is regarded to be the correct one used in gluing technique. The test was carried out using a non-destructive ultrasonic method. It has been shown that the highest decreases in speed of propagation of sound waves are in wood glued with glutinous glue and the lowest in wood glued with cyanoacrylate glue.

Tensile Performance of Traditional and Modern Corner Joints in Wooden Structures

Corner joints are critical points of wooden structures not only in furniture construction but also in traditional wooden architecture, especially in constructions without nails. This study was performed to determine the effects of particular factors such as the axis of assembly, types of material, and adhesive on the tensile performance of various modern and traditional types of wooden corner joints. For this purpose, various corner joint specimens were prepared with three different wooden materials: Scots pine (Pinus sylvestris Lipsky) wood, Lombardy poplar (Populus nigra Lipsky) wood, and Medium Density Fibreboard (MDF) using two different adhesives: polyvinyl acetate (PVAc) and polyurethane (Desmodur-VTKA) glues; and five different wooden joint types: dowel, tongue-and-groove, half-blind dovetail, screw, and eccentric screw joints. Tensile performance tests, vertical and parallel to the axis of assembly, were carried out according to ASTM D 1037 guidelines. Experiments indicated that, while the tensile performance of MDF specimen connected with a screw and PVAc adhesive was the highest under loading parallel to the axis of assembly (4592 N); it was the lowest under loading parallel to the axis of assembly in MDF specimen connected with tongue-and-groove joint and PVAc adhesive (260 N), respectively. As a result, it may be advantageous to apply screwed joints in corners for high tensile strength in parallel to the axis of the assembly.