Adhesive Spread Research Articles

Feasibility of manufacturing cross-laminated timber using fast-grown small diameter eucalyptus lumbers

Eucalyptus is one of the most important plantation species in South China. Alternate applications of plantation grown hardwood such as eucalyptus need to be developed due to decreased demands of fibers for pulp and paper industry. The feasibility of manufacturing three-layer cross-laminated timber (CLT) using fast-grown small diameter eucalyptus wood (Eucalyptus urophylla×Eucalyptus grandis) was evaluated in this study. L9 (33) orthogonal tests with three factors and three levels were adopted to study the effects of adhesive spread rate, pressure, and pressing time duration on the block shear strength (BSS), wood failure percentage (WFP), and rate of delamination (RD) of CLT via block shear tests and cyclic delamination tests. The results indicated that the optimal pressing parameters were adhesive spread rate of 160g/m2, pressing pressure of 0.8MPa, and pressing time duration of 200min with one-component polyurethane adhesive used. The values of modulus of elasticity (MOE) and modulus of rupture (MOR) in the major and minor strength directions of CLT were 11,466MPa, 24.5MPa, 681MPa, and 8.6MPa, respectively. The values of transverse shear moduli and interlaminar shear strength in the major and minor strength directions of CLT were 91.8MPa, 1.3MPa, 241.6MPa, and 0.5MPa, respectively. The mechanical properties of eucalyptus CLT were equivalent to those of commercially available softwood CLT. These results indicate CLT panels manufactured from fast-grown small diameter eucalyptus lumber is promising for structural applications.

Enhanced Fibroblast Cellular Ligamentization Process to Polyethylene Terepthalate Artificial Ligament by Silk Fibroin Coating.

Artificial ligaments utilized in reconstruction of anterior cruciate ligament (ACL) are usually made of polyethylene terepthalate (PET) because of its good mechanical properties in vivo. However, it was found that the deficiencies in hydrophilicity and biocompatibility of PET hindered the process of ligamentization. Therefore, surface modification of the PET is deemed as a solution in resolving such problem. Silk fibroin (SF), which is characterized by good biocompatibility and low immunogenicity in clinical applications, was utilized to prepare a coating on the PET ligament (PET+SF) in this work. At first, decrease of hydrophobicity and appearance of amino groups were found on the surface of artificial PET ligament after coating with SF. Second, mouse fibroblasts were cultured on the two different kinds of ligament in order to clarify the possible effect of SF coating. It was proved that mouse fibroblasts display better adhesion and proliferation on PET+SF than PET ligament according to the results of several technical methods including SEM observation, cell adhesive force and spread area test, and mRNA analysis. Meanwhile, methylthiazolyldiphenyl-tetrazolium bromide and DNA content tests showed that biocompatibility of PET+SF is better than PET ligament. In addition, collagen deposition tests also indicated that the quantity of collagen in PET+SF is higher than PET ligament. Based on these results, it can be concluded that SF coating is suggested to be an effective approach to modify the surface of PET ligament and enhance the "ligamentization" process in vivo accordingly.

Effect of Adhesive Spreading Rate on the Performance of Laminated Compressed Oil Palm Trunks

The large availability and cheap price of oil palm (Elaeis guineensis) trunk makes it an attractive raw material for value-added applications, but its low density and high carbohydrate content are highly undesirable. In this work, oil palm trunk (OPT) was steam-pretreated and compressed at high temperature. The compressed OPT was laminated using polyvinyl acetate (PVAc) using either 250 or 500 g/m2 adhesive spread rate (ASR). Soil burial testing was performed for three months on two different samples to study the deterioration and weight loss by bio-organisms. The laminated, compressed OPT formed with high PVAc ASR was found to be more durable against bio-organisms. The thermal stability of the compressed OPT was studied by thermogravimetric analysis (TGA), and it was observed that the weight loss was lower for steam-pretreated samples compared to those without steam pretreatment. Moisture absorption-desorption testing of compressed OPT was performed, and a hysteresis curve was generated. It was found that laminated, compressed OPTs with 500 g/m2 ASR had lower moisture absorption than those with 250 g/m2 ASR.

Investigation of Glueline Shear Strength of Pine Wood Bonded with PVAc by Response Surface Methodology

The effects of process parameters (adhesive spread, press time, and applied pressure) on the response parameter (shear strength) of pine wood bonded with PVAc were studied. Response surface methodology was applied for design of experiments and for analysis of results. A mathematical model was developed to establish the relationship between the process parameters and response parameters. The results showed that the major factors were adhesive spread and applied pressure. The shear strength increased as the adhesive spread and applied pressure increased within certain ranges.

수분함량에 따른 의치접착제의 확장성 관찰

Purpose: In this study, Spreadability of denture adhesive in accordance with the saturation level of saliva, respectively, by using the resin plate and the glass was measured thickness and Spreadability. Methods: Examine the spreadability of denture adhesive in accordance with the saturation level of saliva, respectively, by using the resin plate and the glass was measured thickness and Spreadability. Also, by measuring the adhesive strength according to the amount of saliva, and the edentulous patients using denture adhesive and dry mouth patients attempt to provide clinical information of the denture adhesive. Therefore, by using the relatively low shrinkage cold curing resin, after fabricating specimen of plate form, for 7 days, it was immersed in water. Results: For the control group only denture adhesive, an artificial saliva for the experimental group were injected in <TEX>$0.1m{\ell}$</TEX>, <TEX>$0.2m{\ell}$</TEX> and <TEX>$0.3m{\ell}$</TEX> of the denture adhesive on the surface, experimental results of the investigation of the 10 times the tensile bond strength of the specimens in each group was obtained the following results. Conclusion: As the time to pressure increase in the same amount of saliva was found that the amount coming out of the denture adhesive, as the amount of saliva in the same pressure increase coming out of many denture adhesives. And the greater the pressure came out a lot of denture adhesives. Spreadability in measuring saliva contact with <TEX>$0.1m{\ell}$</TEX> and <TEX>$2m{\ell}$</TEX> and <TEX>$3m{\ell}$</TEX> group pressured the diameter of the circular was the denture adhesive is small when compared to the group without adding the pressure of 2kg and 3kg put the saliva. The size of the circle is the same amount of saliva denture adhesive spread more pressure showed a greater increase.

Evaluation on layering effects and adhesive rates of laminated compressed composite panels made from oil palm (Elaeis guineensis) fronds

The objective of this study was to evaluate layering effects and adhesive rates of laminated compressed panels manufactured from oil palm (Elaeis guineensis) fronds. Nine types of panels, namely 6-layer, 8-layer and 10-layer bonded with adhesive spread rates of 200 g/m 2 , 250 g/m 2 and 300 g/m 2 were manufactured. The results showed that both bending and internal bonding strength properties all types of panels increased with increasing number of layers and adhesive amount with an exception of 10-layer panels bonded with 300 g/m 2 . Mechanical properties of such samples were slightly reduced due to their possible brittleness as a result of effect of densification, high resin content and temperature. Thickness swelling and water absorption of the samples enhanced with increasing number of layer and adhesive content. 2014 Elsevier Ltd. All rights reserved.

Feasibility of glued laminated timber beams with tropical hardwoods

A feasibility study of glulam was carried out in French Guiana using local wood species. The aim was to determine gluing parameters affording satisfactory behaviour to manufactured glulam in a tropical climate. Three abundant wood species, with special properties, were selected for the study and resorcinol–phenol–formaldehyde resin was used for bonding. Three industrial parameters were considered: adhesive spread rate, closed assembly time and gluing pressure. Delamination and shearing tests were carried out in accordance with European Standards. The tests revealed the influence of wood properties and manufacturing parameters on joint resistance. In fact, the results showed that specific gravity and the shrinkage coefficient greatly influenced the gluing step. Indeed, wood with a medium specific gravity needed more adhesive and more pressure than wood with a high specific gravity. In addition, planing and lamella thickness were found to affect glue joint resistance.

Improved Plywood Strength and Lowered Emissions from Soybean Meal/Melamine Urea-Formaldehyde Adhesives

The objective of this study was to improve the wet shear strength and reduce the formaldehyde emissions for the soybean meal/melamine urea-formaldehyde (MUF) adhesive–bonded plywood by optimizing the hot pressing parameters in plywood manufacturing. An L(44) experimental design was used. A dynamic mechanical analyzer (DMA) was used to study the curing process of the adhesive during hot pressing. The DMA results showed that the storage modulus (E′) first decreased to a minimum at 72.9°C and then increased as the temperature increased to a maximum at 157.2°C. At temperatures higher than 157.2°C, the storage modulus decreased as the temperature increased. The hot press temperature had a significant effect on both the wet shear strength and the formaldehyde emissions from 120°C to 150°C, while no significant effect was found by varying the hot press time from 50 to 80 s/mm and changing the pressure from 0.8 to 1.2 MPa. The adhesive spread rate had a significant effect on the formaldehyde emissions. No significant effect was found on the wet shear strength of plywood by varying the adhesive spread rate from 145 to 205 g/m2. The optimum hot pressing parameters were found: 150°C hot press temperature, 70 s/mm in hot press time, 1.2 MPa in hot press pressure, and 165 g/m2 in adhesive spread rate. Under such optimum processing conditions, the wet shear strength of the plywood was improved by 24.2 percent from 0.95 to 1.18 MPa, while the formaldehyde emissions was reduced by 21.4 percent from 0.28 to 0.22 mg/liter, which met the type II plywood requirement for wet shear strength and the level E0 requirement for formaldehyde emissions described in the China National Standard GB/T 9846.3-2004.

Resistance of phenolic-treated oil palm stem plywood against subterranean termites and white rot decay

The objectives of the study were to evaluate the effectiveness of phenolic resin in protecting oil palm stem (OPS) plywood against both subterranean termites (Coptotermes curvignathus) and white rot fungi (Pycnoporous sanguineus). Specially cooked, Low molecular weight phenol formaldehyde (LMW PF) resin was used to treat the OPS veneer whilst commercial urea formaldehyde (UF) resin was used to bond the phenolic-treated veneer. OPS plywood were produced using two types of lay-up (100% outer veneer type and 100% inner veneer type) with adhesive spread rate of 200g/m2. The results show that treatment of OPS veneer with LMW PF has significantly enhanced the resistance of OPS plywood against both termites and white rot fungi. In the termites resistance test, the percentage of weight loss for untreated samples were 19.2% (outer veneer) and 23.9% (inner veneer), while for phenolic treated samples were only 10.7% and 15.8%, respectively. The phenolic treatment was able to enhance the resistance towards termites by 38% and towards white rot fungi by 62%. The study has shown LMW PF resin can be used to protect OPS plywood from termites and white rot fungi.

A study of the bonding of wood from Eucalyptus grandis W. Hill ex Maiden using resorcinol-formaldehyde adhesive

This work aims to evaluate the strength of joints bonded with thermosetting resorcinol-formaldehyde adhesive, as obtained from three radial and three longitudinal positions relative to the log in wood of Eucalyptus grandis W. Hill ex Maiden (Myrtaceae) at age 18 years, and also to correlate it with basic density. The adhesive spread rate was 250 g/m² using double lines and adding hardener at a rate of one part of hardener to five parts of adhesive. Moisture content in the wood sheets at the time of bonding was 12%. Bonded joints were prepared according to standard ASTM D 2339-98. Basic density values showed an increasing tendency in the pith-to-bark direction while no significant variation was noted in the base-to-top direction. Higher mean values of shear strength and smaller percentages of wood failure were obtained from joints originated in positions close to the bark and to the log base. Overall, the bonding behavior of resorcinol-formaldehyde adhesive in Eucalyptus grandis was found to vary considerably in different positions relative to the log.

The Dominant Factor Analysis of Production Technology of Poplar LVL Based on Grey Theory

Wood is one kind of natural renewable eco-material. Laminated veneer lumber (LVL) is an engineered wood product made from veneers glued together with parallelly oriented grains under heat and pressure. This paper designed Poplar LVL production experiments under different process conditions, and measured the mechanical properties of poplar LVL specimens under different experimental conditions. In this study, grey theory was used to analyze the influences of different production processes on the mechanical properties, such as press duration, press temperature, pressure and adhesive spread. The result showed that, it is feasible that grey theory is used to analyze the influence level of production technology of poplar LVL on the mechanical properties. So this paper offered a new method to analyze and design the production technology of LVL.

Bond strength of end-grain joints and its dependence on surface roughness and adhesive spread

The effect of different machining processes on surface roughness and on adhesive tensile strength of end-grain-bonded spruce wood specimens was studied. Surfaces that had been cut with two different circular saws containing 48 and 96 teeth were compared with those that had been further processed by smoothing with a microtome, machine planing, or sanding. Two different adhesives and two different spreading quantities were used to join the test specimens by their end-grain surfaces. Increasing tensile strength of the bonded specimens was observed with increased surface roughness, which was ascribed to an enlarged bonding area in the case of circular-sawn samples with a rough surface. On the other hand, more pronounced starving of the bond line and thus decreased bond strength was observed in the more open cells of the smoothed end-grain surfaces. A positive effect regarding tensile strength was further observed with increased spreading quantity of the adhesives. Machining was found to particularly affect earlywood tracheids, whereas surface roughness of latewood tracheids was comparable for the differently treated end-grain surfaces

The Dominant Factor Analysis of Dynamic Shear Modulus of Poplar LVL Based on Grey Theory

Wood is one kind of natural renewable eco-material. Laminated veneer lumber (LVL) is an engineered wood product made from veneers glued together with parallelly oriented grains under heat and pressure. This paper designed Poplar LVL production experiments under different process conditions, and measured the mechanical properties of poplar LVL specimens under different experimental conditions. In this study, grey theory was used to analyze the influences of different production processes on the mechanical properties, such as press duration, press temperature, pressure and adhesive spread. The results showed that, it is feasible that grey theory is used to analyze the influence level of production technology of poplar LVL on the mechanical properties. So this paper offered a new method to analyze and design the production technology of LVL.

Properties Enhancement of Oil Palm Plywood through Veneer Pretreatment with Low Molecular Weight Phenol-Formaldehyde Resin

One of the problems dealing with oil palm stem (OPS) plywood is the high veneer surface roughness that results in high resin consumption during the plywood manufacturing. In this study, evaluation was done on the effects of pretreatment of OPS veneers with phenol-formaldehyde resin on the bond integrity and bending strength of OPS plywood. OPS veneers were soaked in low molecular weight phenol-formaldehyde resin (LMW PF) for 20 seconds to obtain certain percentage of resin weight gain. OPS plywoods were produced using two types of lay-ups (100% outer veneer type and 100% inner veneer type) and two urea-formaldehyde (UF) adhesive spread amounts (200 g/m2 and 250 g/m2). The results show that pretreating the veneer with LMW PF could reduce the penetration of the adhesive into the fibres during gluing step. UF adhesive spread amount of 200 g/m2 is sufficient to produce good quality OPS plywood. The technique used in this study was able to enhance the mechanical properties of OPS plywood as well as reduce the amount of resin consumption.

Photocatalytic properties of silicone polyesters using calcium phosphate/titanium dioxide

AbstractThis study uses titanium dioxide treated with calcium phosphate to prepare multilayer structure composites. These products are regarded as photocatalysts. Utilizing polyethylene glycol (PEG)–silicone polyester as an adhesive spread on matrix surfaces, this can provide these products with antifouling properties, good weather resistance, and antibacterial property. It has been observed that UV irradiation has caused changes in the film molecular structure of PEG–silicone polyesters, as well as changes in the surface morphology. These changes in molecular structure have been observed by FTIR and Raman analysis. PEG–silicone polyesters contain silicon atoms with both organic and inorganic characteristics. This makes fixation of photocatalysts possible and retards oxidation of organic materials in the polyesters. The results of FTIR and Raman spectrum analyses indicate films made of these polyesters effectively cover calcium phosphate–titanium dioxide photocatalysts, retard surface cracks, and slow down decomposition, caused by UV light. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The Optimum Design of Production Technology of the Poplar LVL

In this paper, the production technology of laminated veneer lumber was optimized by using the uniform design method. The effects of production technology, such as the press duration, the press temperature, the press pressure and the adhesive spread, were found statistically significant on some mechanical properties of LVL. So in this paper, the thickness of LVL board was a fixed value, but the press duration, the press temperature and the adhesive spread were variable. The modulus of elasticity (MOE) and static bending strength (MOR) as predicted by the ANN approach and the regression functions were compared with the experimental values. It was shown that the proposed neural network model was able to predict valuable mechanical properties, such as the modulus of elasticity and static bending strength, that would facilitate the development of optimum design of properties for manufacturing high quality materials.

Tensile strength of softwood butt end joints. Part 2: Improvement of bond strength by a hydroxymethylated resorcinol primer

In a previous study it was shown that the mechanical stability of an end-grain joint bonded with a one-component polyurethane adhesive (PUR) was insufficient compared with melamine–urea–formaldehyde and phenol–resorcinol–formaldehyde bonding. Based on this, the aim of this study was to improve the mechanical stability of the end-grain joint by means of a hydroxymethylated resorcinol (HMR) primer and by increasing the spreading quantity. To study the effect of HMR and the increased spreading quantity on the adhesive bond strength of end-grain to end-grain-bonded wood samples, three-part Norway spruce wood specimens were tested in tension. Before bonding, each end-grain surface was treated with an aqueous solution of HMR. The two axially orientated outer parts of the specimens were jointed with the middle part using a PUR adhesive. Compared with untreated, i.e. non-primed samples, the tensile strength of HMR-treated specimens was more than doubled. Furthermore, a positive effect of increased adhesive spread was shown for untreated PUR-bonded samples. An increase in adhesive spread by a factor of 1.6 led to an improvement in tensile strength by a factor of about 2.6.

Regulador vegetal e bioestimulante na indução floral do maracujazeiro-amarelo em condições de entressafra

O objetivo do trabalho foi avaliar o efeito de regulador vegetal e de bioestimulante na indução floral do maracujazeiro-amarelo em condições não-indutivas, em Araguari-MG. Foram identificados e podados 12 ramos terciários por parcela (02-04-05), sendo 6 deles expostos de um lado da espaldeira, com luminosidade predominante pela manhã e 6 do outro lado da espaldeira, com luminosidade à tarde. O delineamento experimental foi em parcelas subdivididas, com 7 tratamentos principais (parcelas): 0mg L-1 (testemunha); 100mg L-1; 200mg L-1 e 300mg L-1 de regulador vegetal GA3 (i.a.); 2,08 mL L-1; 4,17mL L-1 e 6,25mL L-1 de bioestimulante Stimulate® (i.a.), em duas aplicações foliares (09-04-02 e 09-05-02), acrescidas de espalhante adesivo Silwett® a 0,05%. Além desses, foram utilizados 2 tratamentos secundários (subparcelas): exposição dos ramos à luminosidade da manhã e da tarde, com 4 repetições de 3 plantas por parcela. Cada subparcela foi um dos dois lados da espaldeira. As médias foram comparadas pelo teste de Tukey, a 5% de probabilidade. Realizou-se, aos 75 dias, a avaliação nos dois lados da espaldeira do comprimento dos ramos e entrenós, número de nós, de folhas e de botões florais. As variáveis estudadas não foram influenciadas pelo uso de GA3 e Stimulate®, no entanto houve diferença quando os ramos ficaram expostos à luminosidade da manhã em relação àqueles com luminosidade à tarde.

The Effects of Cold Plasma Treatments on LDPE Wettability and Curing Kinetic of a Polyurethane Adhesive

AbstractA cold plasma feed with either oxygen or nitrogen was used to modify thin Low Density Polyethylene films. The treatment improved both the surface wettability and the curing kinetic of a polyurethane based adhesive spread on the surface. The chemical functionalities responsible of the observed behaviours were investigated and monitored over time by high resolution x‐ray photoelectron spectroscopy. Atomic force microscopy were used to compare the effects of the two feeding gases on the surface morphology of films exposed (to the plasma) for equal times. The effect on the treated films of the atmosphere exposure and of the aging time were also considered.

Electrically Conductive Adhesive Formulations for SMT Applications

The aim of current research presented in my paper is to establish how adhesive composition influences the performance of joints between SMDs and PCBs. For identifying the best adhesive formulation in SMT applications, the experiment design method based on Taguchi techniques for quality engineering has been used. It was decided to investigate how the following controllable factors: type of isolating resin, levels of weight content of Ag filler, presence of adhesive promoter and spread improver as well as PCB pads finishing influences the performance of adhesive joints. As the figure-of-merit, the individual joint resistance and adhesion between SMDs and PCBs were measured. It was found that the type of resin had the biggest influence on electrical and mechanical properties of adhesive joints.