Adhesive Research Papers - Academia.edu (original) (raw)

This paper presents the preliminary findings of pH and colour measurements carried out on artworks on paper and on wood that had been treated with a poly(vinyl acetate) (PVAC) based adhesive in the 1980s. In both cases, areas treated with PVAC proved to be less acidic than untreated areas. Contrary to expectations, the conservation treatments have not, as yet, increased acidity levels in the objects under study. Colour measurements of the works on paper showed that those that had been backed with a cotton fabric using a mixture of methylcellulose and PVAC were less yellow than those from the same print run that had not been backed. This finding suggests that the backing somehow prevented the natural degradation of the support. In view of these preliminary results, further research is clearly needed. This study forms part of a broader ongoing project to assess the role of PVAC in the conservation of a range of cultural assets.

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- Cultural Heritage, Adhesive, PVAc, Conservation & Restoration research

Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs), this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%-50% at rotor rotational speeds of 15-45 rpm and filled coefficients of 0.55-0.75. Four regression equations, i.e., the tensile strength (Ts), elongation at break (Eb), hardness (Ha) and rebound resilience (Rr) as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the Ts, Eb and Rr of the panels were reduced, Ha was considerably increased by 17%-58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%-3%, which was much lower than commercial wood-based composites.

- by Liping Cai
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- Engineering, Materials Science, Materials, Adhesive

The tensile strength of beech substrates bonded with dispersions of alkali-denatured soy protein isolate (SPI) and wheat gluten (WG) was measured for comparison of bond strength and resistance to cold water. The proteins were denatured with 0.1 M NaOH (pH 13). Dispersions with different protein concentration and viscosity were investigated. The adhesive properties were studied at different press temperatures (90, 110, and 130 1C) and press times (5, 15, and 25 min). Two types of application methods were used in order to overcome the problem with different viscosity of the dispersions. In addition, SPI was denatured at two different pH levels (approximately 10 and 13) and with two different concentrations of salt (158 mM and 0.1 M), in order to compensate for the different isoelectric points of the proteins. The adhesive properties of WG powder with different particle sizes were also compared. The tensile strengths of the wood substrates were measured according to somewhat simplified versions of the European Standards EN 204 and EN 205. The bond lines were studied with light microscopy. The results indicate that the adhesive properties of SPI are superior, particularly with regard to water resistance. However, the water resistance of WG was to some extent improved when starved adhesive joints could be avoided. Similar tensile strength values were obtained for the dispersions of alkalidenatured SPI regardless of pH or salt concentration. No apparent difference in adhesive strength was observed for the WG dispersions from powder with different particle sizes.

- by Eva Malmström
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- Materials Engineering, Mechanical Engineering, Chemical Engineering, Collage

The increasing demands from environmental legislations are changing the conditions that the valve system is exposed to in heavy duty engines. Increased pressures, higher temperatures and lower amounts of soot which can build up a protective film are some of the increasing challenges which the system has to endure. Three pairs of valves and valve seat inserts with the same material and design properties but with different service condition have been analyzed with a variety of analytical instruments to gain information of how the wear occurs. The wear mechanisms found were a combination of oxidation, where many different oxides were found, adhesive wear, which was seen both in form of material transfer and flow lines. On top of Sample Mild and Hard there were tribo films of thickness varying from 1 to 5 m consisting of Ca, O, P, S and Zn. The film has in all cases protected the underlying surface from wear but in some cases seems to have a corrosive impact instead.

- by Staffan Jacobson
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- Materials Engineering, Mechanical Engineering, Oxidative Stress, Wear

The research and development of connecting and strengthening timber structural elements with 3 glued-in rods (GiR) has been ongoing since the 1980s. Despite many successful applications in 4 practice, agreement regarding design criteria has not been reached. This state-of-the-art review 5 summarises results from both research and practical applications regarding connections and 6 reinforcement with GiR. The review considers manufacturing methods, mechanisms and 7 parameters governing the performance and strength of GiR, theoretical approaches to estimate 8 their load-bearing capacity and existing design recommendations. 9 Keywords 10 Reinforcement, steel rod, FRP rod, design, application, adhesive, Eurocode 5, quality control, 11 linear elastic fracture mechanics, non-linear elastic fracture mechanics 12

- by Mislav Stepinac
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- Civil Engineering, Design, Quality Control, Adhesive

This study was aimed at the application of keratin-modified-urea-formaldehyde (KMUF) resin adhesive for bonding particleboard. The keratin extract was used in developing the urea- formaldehyde resin. The physicochemical properties of the resins which included viscosity, gel time, specific gravity, pH and total solid content of the modified resins were determined. The application of the resin adhesives was done by formulating and forming particle board whose compositions were 80% wood chips, 11% resins and moisture content of approximately 9%.The boards were evaluated for their mechanochemical and water resistance properties. These properties of KMUF boards were compared with that of neat urea-formaldehyde (NUF) board. The results of the characteristics properties of the particleboards showed that KMUF gave improved strengths and better water resistance properties than the NUF board. Key word: Keratin,application, bonding resin,adhesive, particleboard.

- by PAUL DIM
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- Materials Science, Adhesive, Keratin, Bonding
- by Jean-Denis Mathias
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- Engineering, Adhesive, Reinforcement, Shear Stress
- by Joan Reifsnyder
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- Adhesive, Technique

For high-temperature usage (200 C and above) such as in certain supersonic aircraft structures, the adhesives used are either bismaleimides or polyimides, generally supplied as films, with or without a carrier. Other adhesives, such as... more

- by Lucas Santos
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- Materials Engineering, Mechanical Engineering, Chemical Engineering, Adhesion

This paper presents the ®rst results of research on the migration of adhesive components in the paper and paperboard packaging sector. It examines components that can migrate from a variety of commonly used adhesives in the framework of a`worst case' scenario in respect of the contents. The report also explains the methodology used to analyse extraction and migration and the model used for calculating the transfers.

- by Anita Gruner
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- Mechanical Engineering, Migration, Evaluation, Comparative Study

The applicable scope of adhesives in the current society is broad and currently, several types of PVAc resin are sold in the market for adhesives. PVAc resin is primarily used for wood works and paper adhesion. However, the PVAc resin itself has the disadvantages that its viscosity is highly temperature-dependent and the work condition and viscosity get worse at the low temperature in the winter seasons. Although phthalate-based plasticizer is used to complement these disadvantages, adhesion strength and heat-resistance are weakened by adding the phthalate-based plasticizer and in the winter period, the amount of quantity should be increased. Also in a high-density product, it worsens the work condition by causing a rise of viscosity and delays curing and in a low-density product, it worsens the storage stability by causing separate precipitation. In addition to these, the phthalate-based plasticizer as a material of causing environmental hormones is currently restricted in the advanced countries for its amount of use and also in the domestic market, it is necessary to prepare for the situation. This study has not only eliminated the disadvantages of PVAc resin emulsion without adding a phthalate-based plasticizer of causing these problems, but also synthesized the PVAc resin for timber adhesion that is excellent in woodwork, thermal-resistance, water-resistance, storage stability, and adhesion performance. As the result, it has proven an excellent performance in thermal resistance, water resistance, storage stability, and minimum film forming temperature.

- by Ahmed Ali
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- Adhesive, Wood, PVAc

When a concrete surface is contaminated by water due to rain, saline water, ground water, and water jetty treatment, water, alkalis, and other contaminants on the concrete surface may interact with an epoxy adhesive used for bonding fiber-reinforced polymer composite sheets to concrete. This can influence both the curing rate and the degree of cure of the curing reaction. This in turn can affect the time required for field application. It can also influence the mechanical properties and durability of epoxy adhesives. In this paper, water effects on the curing and properties of two kinds of commercial adhesives were evaluated. Curing kinetics were studied using isothermal DSC analysis. Results showed that water accelerated the curing reaction. However, excess water offsets part of the accelerating effect. While water is typically considered to be harmful to properties of adhesives, it was seen that a small amount (less than 2%) of water improved degree of cure, mechanical properties, and durability of adhesives.

- by Suong Hoa
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- Engineering, Materials Science, Water, Kinetics

A soy-based formaldehyde-free adhesive consisting of soy flour (SF) and a curing agent (CA) has been successfully used for the production of plywood. However, this adhesive cannot be easily sprayed onto wood particles for making... more

A systematic study of the production of poly(2-ethyl hexyl acrylate/methyl methacrylate/acrylic acid) pressure-sensitive adhesives (PSAs) via conventional emulsion and miniemulsion polymerization was carried out in order to discern and compare the influence of copolymer composition, chain transfer agent (CTA) and surfactant concentrations on the kinetics and microstructure of the resulting adhesive films. The results showed that miniemulsion polymerization proceeded solely under droplet nucleation for a certain set of initial reaction conditions. The miniemulsion-based latexes presented a polymer microstructure that was different to that found in latexes produced by conventional emulsion polymerization, as observed in the frequency master curves and PSA performance analysis. Batch miniemulsion polymerization was able to produce films with entanglement densities (M w /M e) from 2 up to 11, which were strongly correlated with loop tack, peel strength and shear strength. Conversely, under the same reaction conditions, batch conventional emulsion polymerization was only able to produce M w /M e ratios below 2.

- by Gabriela Fonseca
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- Mechanical Engineering, Chemical Engineering, Microstructure, Viscoelasticity

Small amounts of fluorinated polyethers, and in particular a nonionic fluorinated polyether, can upgrade considerably the cold-water swelling and internal bond strength of wood particleboard bonded with urea–formaldehyde (UF) resins. The effect is maximized at an additive concentration of about 0.1 wt % with respect to the adhesive resin solid content. The effect of the fluorinated polyether appears to be greater with older UF resins, which have a more pronounced colloidal state. The mechanism appears to be somewhat related to the reduction of the interfacial tension of the resins, with improved substrate wetting leading to better adhesion. The addition of a fluorinated polyether well in advance of resin use further enhances the improvement. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

- by Thomas Garnier
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- Engineering, Polymer Blends, Adhesive, Wood

ABSTRACT The rheological and adhesive properties of bis-urea functionalized low-molecular-weight polyisobutylenes (PIBUT) are investigated. The polymers, which can interact through supramolecular hydrogen bonds, can self-organize over times of the order of days at room temperature. This organized structure has been identified by small angle X-ray scattering (SAXS) and its rheological properties indicate the behaviour of a soft viscoelastic gel. The ordered structure can be disrupted by temperature and shear so that at 80 °C, the material behaves as a highly viscoelastic fluid and no SAXS peak is observed. When cooled back at room temperature, the PIBUT retrieves its ordered structure and gel properties after 20 h of annealing. This very slow molecular dynamics gives PIBUT a highly dissipative nature upon deformation, which combined with strongly interacting moieties results in very interesting adhesive properties both on steel surfaces but more importantly on typical low adhesion surfaces such as silicone. A strategy based on the controlled incorporation of supramolecular bonds in a covalently crosslinked network appears promising for the development of a new generation of highly interacting and dissipative soft adhesives.

- by Corinne Chaneac
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- Engineering, Materials Science, Supramolecular Chemistry, Rheology
- by Syed Imam
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- Comparative Study, Adhesive, Viscosity, Crosslinking

Objective: The aim of this study is to create a standard test to approve the efficacy of a surgical sealant. An industrial test, the bulge-andblister test, which is very convenient for measuring adhesion energy, is applied to the surgical field to quantify adhesion of bioadhesives. Methods: Samples were composed of two circular layers of equine pericardium glued by the surgical sealant studied. The sample was fixed to a support with an industrial glue. The support and the bottom layer were perforated in the centre to allow injection of pressurised water. Water was progressively introduced through the hole in the support and the bottom layer to create a blister with constant radius, increasing height and internal pressure during this first step. At a critical pressure, delamination started, the radius and height of the blister increased and the pressure decreased. At this point, the adhesion energy could be determined. The experimental parameters were measured with a pressure sensor and an optical profilometry device for deflection. Results: Adhesion testing was carried out in eight paired equine pericardium samples bonded with a Dermabond W cyanoacrylate glue. The average value of the practical adhesion energy is 2.3 J m À2 with a standard deviation of 1.5 J m À2 . Conclusion: Application of the bulge-and-blister test to the surgical field was achieved and allowed a quantification of adhesion of a surgical glue. Such information is essential to compare the different surgical glues presently available. The study of the impact of bonding conditions such as pressure, hygrometry or setting conditions will provide a better understanding of the characteristics of adhesion in the surgical field. #

- by Michel Dupeux
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- Cardiology, Adhesion, Adhesive, Standard Deviation

Discusses the uses and characteristics of two glue-paste lining adhesives (Florentine paste and Roman paste) used in Italy and presents a brief history of these adhesives based on two major Italian 19th-century literary sources, Manuale Ragionato per la Parte Meccanica dell'Arte del Ristauratore de Dipinti by Giovanni Secco-Suardo, and Manuale del Pittore Restauratore by Ulisse Forni. The results of the tests with lined facsimiles are discussed in terms of weight differences, flexibility, reversibility, and ground preparation shifting as a result of water content of the adhesives. There are many different recipes and types of glue-paste compositions; not all have the same characteristics, consistency, or working results.

- by Joan Reifsnyder
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- Engineering, Adhesive, Technique

Vulcanized rubbers contain different low molecular weight additives in their formulation, including antiozonants, plasticizers, oils, etc. These moieties-mostly paraffin wax-often migrate to the surface causing a weak boundary layer of non-rubber contaminants which is deleterious for adhesion of rubber to adhesives (such as polyurethane and polychloroprene adhesives). One of the key steps in the manufacturing of rubber/adhesive joints is the reactivation, i.e. sudden heating of the thin adhesive layers on the substrates to be joined under infrared (IR) radiation to 80-90 1C for a few seconds to allow diffusion of the polymeric chains under pressure. This reactivation may cause the migration of low molecular weight additives to the rubber surface causing a lack of adhesion. The main aim of this study was to .identify the influence of the reactivation temperature (40 to 170 1C) on the surface properties of sulphur vulcanized styrene-butadiene rubber and determine the extent of the diffusion of paraffin wax and zinc stearate to the rubber surface. The changes produced on the rubber surface were measured immediately after reactivation treatment by ethylene glycol contact angle measurements, attenuated total reflectance infrared spectroscopy (ATR-IR) and scanning electron microscopy (SEM). Additionally, the weight loss of the rubber after reactivation at different temperatures was recorded. The reactivation of the rubber at different temperatures produced changes in the morphology and thickness of the paraffin wax layer on the surface. By heating at temperature close to that of the paraffin wax melting point, the paraffin wax migration was favoured and at the same time the crystals of paraffin wax on the rubber surface were melted. As a consequence a thicker and smoother film of melting paraffin wax was formed. By increasing the reactivation temperature, a partial removal of paraffin wax was produced and the thickness of the paraffin wax film on the rubber surface was reduced. For reactivation temperatures below 90 1C, the higher the temperature, the lower the weight loss of the rubber, because the increase in the surface area of the melted paraffin wax layer that prevented migration from the rubber bulk. However, for reactivation temperature higher than 90 1C, the weight loss of the rubber increased with the reactivation temperature and this was likely due to sublimation of the paraffin wax on the rubber surface. Besides, even after reactivation at 170 1C, a thin film of paraffin wax always remained on the rubber surface as was evidenced by contact angle measurements. On the other hand, a critical reactivation temperature at 90-100 1C existed at which the migration of zinc stearate to the paraffin wax layer on the rubber surface was favoured.

- by F. Lebon
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- Mechanical Engineering, Civil Engineering, Applied Mathematics, Materials Science

"El proyecto de investigación que llevamos a cabo (...) tiene como objetivo principal la localización de las pinturas murales traspasadas con PVAc. Una vez localizadas se procederá a la elaboración de un catálogo donde quedará registrado un diagnóstico del estado de conservación de las pinturas, lo que nos permitirá conocer el alcance de los problemas que ha causado el adhesivo vinílico."

- by Anna Nualart-Torroja
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- Adhesive, PVAc, Pintura mural arrancada, Conservation & Restoration research

Exfoliating creams were packed in sachets of composite packaging consisting of polyethylene, aluminium and polyester layers stuck together by polyurethane adhesive, and they were kept in an oven at 40°C in order to accelerate the delamination process. The sachets were then delaminated and the resulting layers were analysed. A headspace solid-phase microextraction mass spectrometry method (HS–SPME–GC–MS) using a 75µm carboxen polydimethylsiloxane fibre was used to identify the compounds migrating from the exfoliating creams through the polyethylene layer to the aluminium interface and suspected to be responsible for packaging delamination. Several volatile compounds used in the cosmetic industry as perfumes, fixing agents and preservatives, such as menthol, dihydromyrcenol and 2-phenoxyethanol, were detected in the aluminium/polyester delaminated layer. The exfoliating creams were also analysed by HS–SPME–GC–MS. The study of loss of adhesion of the laminated material exposed to the exfoliating products revealed that the product with a higher concentration of 2-phenoxyethanol caused a faster decrease in adhesion strength, but the lower adhesion values were found in products with higher concentrations of menthol and dihydromyrcenol. The results obtained showed that the analytical method used was suitable for identifying volatile compounds that migrate through polyethylene to the inner layers of the packaging of exfoliating products, as well as for providing prior information on which products may be difficult to package in sachets. Copyright © 2006 John Wiley & Sons, Ltd.

- by Gustavo Ortiz
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- Mechanical Engineering, Migration, Heat Treatment, Adhesive
- by Samuel Kenig
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- Engineering, Adhesive, Properties, Aerospace Industry

Polyvinyl acetate (PVA), a thermoplastic polymer, has poor performance at elevated temperatures and humid conditions as a wood adhesive. Two types of hydrophilic nano-clay were mixed at different loadings (1%, 2% and 4%) with PVA to improve the performance of PVA towards water and elevated temperatures. The properties of PVA-clay nanocomposites were characterized by measuring the shear strength of wood block shear-type assemblies bonded with new formulated adhesives in dry and wet, and also, at elevated temperatures. Thermal stability and structure of the PVA-clay nanocomposites were studied by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that shear strength of wood joints increased in all states by adding nano-clay to PVA. Inclusion of nano-clay improved the thermal stability of PVA to different degrees depending on nano-clay loading and type. The morphological studies revealed that the fluctuations observed in thermal stability and bond strength of the nanocomposites stem from dispersion quality of nano-clay.

Additives for epoxy resin systems, both silane coupling agents and silicones and epoxy functional siloxanes are discussed. Topics include: Silane Coupling Agents, Difunctional and Multifunctional Epoxy-Terminated Silicones, Silicone Resin Modifiers, Monofunctional Silicones, Cycloaliphatic Silanes and Silicones, Silane and Silicone Hardeners. Electrical, optical and thermal properties are considered.

- by Barry Arkles
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- Adhesive, Epoxy Resins, Toughness Epoxy Resin, Adhesives

The production of adhesive from cassava root IITA variety TMS 94/0026 was performed. Applications of starch based adhesive are limited due to its unsuitable properties. Improvements in properties of adhesives produced were achieved by investigating the effects of temperature, mass (concentration) of the viscosity enhancer /stabilizer (borax) and gelatinization modifier (acidic, hydrogen chloride acid (HCl) and basic sodium hydroxide (NaOH)) and its concentration on the properties (viscosity, density and pH) of the adhesive produced. The effect of the gelatinization modifier (HCL and NaOH) on the drying time and bond strength of the adhesive was also investigated. Results obtained provide a wide range of conditions for producing starch-based adhesives for diverse applications and required properties. The adhesives produced with sodium hydroxide as its gelatinization modifier had a stronger bond and a maximum drying time of 7.20 minutes compared to a drying time of 4.16 minutes for the adhesive produced with hydrogen chloride acid.

- by Jackson Akpa
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- Adhesive

In this study blending PVA with MUF and MF was evaluated as an approach to enhance the performance of PVA towards water and elevated temperatures. MF and MUF were added to PVA at different proportions: 15%, 30%, 50%, 70% and 100%. Blends of PVA with MF and MUF were used as adhesives to bond wood joints. The shear strength of wood joints was measured at dry and wet states, and elevated temperatures. Thermogravimetric analysis was used to study thermal stability of PVA and its blends with MF and MUF. The structural changes caused by the inclusions were characterized by Fourier transforms infrared spectroscopy (FT-IR). The results showed that shear strength of wood joints were improved by the addition of MF and MUF to PVA in all conditions. Adding small amounts of MUF or MF (as low as 15%) enhanced the performance of wood joints towards water and elevated temperatures. The extent of improvement was sometimes so high that the strength of glue line surpassed strength of wood in wet conditions leading to wood failure rather than glue failure. MF had more effectiveness in improving shear strength of wood joints than MUF in all conditions. Thermal stability of PVA was increased by MF but the effect of MUF on thermal stability of PVA was dependent on MUF proportions and temperatures. FT-IR analyses showed that there are some chemical bonds between PVA and MF. Considering costs, effectiveness and formaldehyde emission, adding 15% MF to PVA seems the optimal proportion of MF in the PVA blends.

- by Alireza Kaboorani
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- Materials Engineering, Mechanical Engineering, Chemical Engineering, Collage

Resin-Bonded Fixed Partial Dentures (RBFPD) was introduced to dentistry around 40 years ago. The typical design of resin-bonded fixed partial denture is characterized by conservation of tooth structure of abutment compared to fixed treatment. This article presents a case report of a patient who reported with missing maxillary central incisor. Multiple treatment options are available for replacement of missing tooth. Use of conventional fixed partial denture in such a situation is criticized because modern dental practice revolves around the principle of preservation of tooth structure. So in such cases resin bonded fixed partial denture is best treatment option.

- by antonio tarsia
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- Dentistry, Restorative Dentistry And Endodontics, Adhesive

This study was aimed at the application of keratin-modified-urea-formaldehyde (KMUF) resin adhesive for bonding particleboard. The keratin extract was used in developing the ureaformaldehyde resin. The physicochemical properties of the resins which included viscosity, gel time, specific gravity, pH and total solid content of the modified resins were determined. The application of the resin adhesives was done by formulating and forming particle board whose compositions were 80 % wood chips, 11 % resins and moisture content of approximately 9%.The boards were evaluated for their mechanochemical and water resistance properties. These properties of KMUF boards were compared with that of neat urea-formaldehyde (NUF) board. The results of the characteristics properties of the particleboards showed that KMUF gave improved strengths and better water resistance properties than the NUF board.

- by PAUL DIM
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- Adhesive, Keratin, Bonding, Particleboard

A novel reactive hot melt adhesive was prepared by coating an epoxy resin on maleic anhydride grafted polyethylene (MAPE) powder. This adhesive had markedly improved adhesion power compared with pristine MAPE powder, which is normally used as a hot melt adhesive. The generation of an ester linkage by the reaction between the anhydride group of MAPE and the hydroxyl group of epoxy resin, during the bonding operation at 190 C with the pressure of 22 MPa for 30 min, was confirmed from the FTIR spectra. The bond strength was further improved by a small amount of 1-methylimidazole, which accelerated the esterification reaction. When the epoxy resin was coated on hydrated MAPE, in which the anhydride group of MAPE was converted into carboxylic acid group by the reaction with water, the esterification reaction was much faster than that of pristine MAPE, and consequently, the bond strength of the adhesive was much higher than that of pristine MAPE coated with epoxy resin.

- by Jin Young Jang
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- Engineering, Adhesive, Infrared spectroscopy, Applied
- by Syed Imam
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- Comparative Study, Adhesive, Viscosity, Crosslinking

Lascaux 360HV/498HV and Vinamul 3252 were brushed onto dry silk crépeline substrate in various ratios. The main areas of concern was the silk covering the brim which had split and weakened around the outer edge due to varying tension and abrasion between the stiff card and fine silk (Fig 2). The top of the crown and inner bavolet (curtain) had significant areas of loss and the ribbons were torn and partially detached from the brim due to wear and mishandling. The deterioration of the silk resembled the industrial practice of silk weighting. Acetone and Industrial Methylated Spirit (IMS) were tested for solvent re-activation and a small heated spatula iron for heat re-activation. A mock-up of the silk covered brim was made mimicking the deterioration patterns of the bonnet to authenticate assessment for handling during treatment and adhesive testing (Fig 3). Aged satin silk and deteriorated silk ribbons were used to replicate the bonnet's ribbons and bavolet. Table 1 presents the results of the testing including the effects of adhesion. Conclusions: Lascaux 360HV/498HV and solvent reactivation with IMS were selected for final treatment of the bonnet. Although extensive, the adhesive treatment has stabilized a fragile three-dimensional object enabling safe storage and the potential for display and research. 'Coal Scuttle' bonnets are common items which are found in many social history collections around the world. Despite their commonality, they are rarely documented and conserved. The results derived from this case study will help define future adhesive treatments of such common objects whilst maintaining textural manufacturing techniques such as the paper and starched cotton lining of the crown. Notes: 1 Warp-float face of a 4/1 satin weave with predominant warp.

Better fatigue performance of adhesively bonded joints makes them suitable for most structural applications. However, predicting the service life of bonded joints accurately remains a challenge. In this present study, nonlinear computational simulations have been performed on adhesively bonded single lap ASTM-D1002 shear joint considering both geometrical and material nonlinearities to predict the fatigue life by judiciously applying the modified Coffin-Manson equation for adhesive joints. Elastoplastic material models have been employed for both the adhesive and the adherends. The predicted life has close agreement in the high cycle fatigue (HCF) regime with empirical observations reported in the literature.

- by sanjay kumar
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- Materials Engineering, Mechanical Engineering, Chemical Engineering, Modeling

The easy, low-cost modification of the polarity of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) through blending with oxidized Fischer-Tropsch wax was investigated. A 10 wt % concentration of the wax increased the polar component of the total surface free energy 10 times for LDPE and 4.5 times for HDPE. Modified LDPE also had significantly higher adhesion to the polar substrate, which was represented by a crosslinked epoxy-based resin. This behavior was not observed for HDPE. The conservation of the good mechanical properties of polyethylene was observed. The wax content had only a moderate influence on the mechanical properties.

- by Igor Novak
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- Engineering, Adhesion, Polymer Blends, Adhesive

Solventless adhesives from renewable sources are greatly appreciated by the researches since they can be produced at low prices and can be biodegradable, as compared to those produced from petrochemical sources. In this work, solventless castor oil-based polyurethane (PU) adhesives were prepared to evaluate the influence of the NCO/OH molar ratio and the chemical nature of the substrates (wood/wood and foam/foam) on the adhesive force. The solventless castor oil-based PU adhesives were prepared with NCO/OH molar ratios of 1, 2, or 3 having dibutyltin dilaurate (DBTL) and triethylenediamine (TEDA) as catalysts. The adhesives were characterized by FT-IR spectroscopy, differential scanning calorimetry, and thermogravimetric analyses. The tack-free time of the solventless PU adhesives was dependent on the catalyst concentration, and their mechanical properties were influenced by the NCO/OH molar ratio. The solventless PU adhesive foam joints showed peeling strength values 75% higher than that of a solvent-based commercial adhesive currently applied in the mattress industry. The solventless PU adhesive wood joints showed lap shear strength values 20% higher than that of a commercialized solvent-based adhesive used for wood.

Over the last decade, an extreme increase in the application of fiber reinforced polymers (FRPs) for strengthening of reinforced concrete (RC) structures has been observed. The most common technique for strengthening of RC members utilizing FRP reinforcements is externally bonded reinforcement (EBR) technique. Despite certain benefits of the technique such as simple and rapid installation, the main problem which has greatly hampered the use of EBR method is premature debonding of FRP composite from concrete substrate. Recently, grooving method (GM) has been introduced as an alternative to conventional EBR technique. Grooving with the special technique of externally bonded reinforcement on grooves (EBROG) has yielded promising results in postponing or, in some cases, completely elimination of undesirable debonding failure in flexural/shear strengthened RC beams. Consequently, the main intention of the current study is to make a comparison between FRP-to-concrete bond behavior of EBR and EBROG techniques by means of single-shear bond tests. To do so, CFRP sheets were adhered to 16 concrete prism specimens using EBR and EBROG techniques. The specimens were then subjected to single-shear bond test and the results were compared. A non-contact, full field deformation measurement technique, i.e. particle image velocimetry (PIV) was utilized to investigate the bond behavior of the strengthened specimens. Successive digital images were taken from each specimen undergoing deformation during the test process. Images were then analyzed utilizing PIV method and load-slip behavior as well as slip and strain profiles along the strengthening CFRP strips were reported. Experimental results of the current study strongly verify the capability of GM for strengthening RC members to completely eliminate the debonding failure.

- by Davood Mostofinejad
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- Engineering, Particle Image Velocimetry, Adhesive, Composite Material

Determining the performance of polymeric consolidants for fragile, multilayered decorative coatings is a great challenge. A new method is presented to detail the mechanical strengthening effect consolidants have on coating structures. Research was undertaken using East Asian lacquer coatings as an example of multilayered coatings showing brittle fracture and delamination.
A survey identified gesso-type foundation layers to be the least stable layers in the coatings. Mechanical strength tests performed with the standardised double cantilever beam (DCB) method measured the fracture energy (GIc) to characterise the fracture behaviour of the brittle layer. DCB specimens were fractured, then consolidated with polymer formulations and re-fractured to provide data for direct comparison. Consolidants included hide glue, cold-liquid fish glue, isinglass, starch/isinglass, Lascaux Medium for Consolidation (MfK), Paraloid B72 and B48N, Mowiol 3-83, Mowilith 50 and DMC2, and East Asian lacquer (urushi). For undamaged foundation layers, GIc=47(±22) J/m2 was measured. Results for consolidated specimens varied widely. Paraloid and fish glue showed great decreases in mean GIc (down to - 98 %), Lascaux MfC and Mowilith DMC2 gave the greatest increases (up to +180%). Further information on the penetration and void-filling ability of consolidants was provided by cross-sections of the DCB specimens, which matched the results of the measured GIc.
The results showed that differences in the fracture energy, the penetration behaviour of the consolidants, and the location of crack path propagation are measurable using the DCB method. These data provide a much improved understanding of the strengthening capability of different consolidants.

This study investigated the relationship between the hydrolytic stability and the crystalline regions of cured UF resins with different formaldehyde/urea (F/U) mole ratios to better understand the hydrolysis of cured urea-formaldehyde (UF) resin adhesives responsible for its formaldehyde emission in service. As the F/U mole ratio decreased, the hydrolytic stability of cured UF resins improved, but decreased when the particle size of the resin was reduced. To further understand the improved hydrolytic stability of cured UF resin with lower F/U mole ratios, X-ray diffraction (XRD) was extensively used to examine the crystalline part of cured UF resins, depending on F/U mole ratios, cure temperature and time, hardener type and level. Cured UF resins with higher F/U mole ratios (1.6 and 1.4) showed amorphous structure, while those with lower F/U mole ratios (1.2 and 1.0) showed crystalline regions, which could partially explain the improved hydrolytic stability of the cured UF resin. The crystalline part intensity increased as cure temperature, cure time and hardener content increased. But the 2y angles of these crystalline regions did not change, depending on cure temperature and time, hardener type and level, suggesting that the crystalline regions of the cured UF resin were inherent. This study indicates that the crystalline regions of cured UF resins with lower F/U mole ratio contribute partially to the improved hydrolytic stability of the cured resin.

- by Ho Won Jeong
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- Materials Engineering, Mechanical Engineering, Chemical Engineering, Adhesive

Cet article a trait au renforcement à l'effort tranchant des poutres en béton armé à l'aide de matériaux composites collés en surface. Il présente une synthèse des prescriptions de la norme ACNOR (Association canadienne de normalisation) S806-02 relatives au renforcement à l'effort tranchant, en comparaison aux autres guides internationaux existants. Il présente également une analyse exhaustive des paramètres majeurs influençant la contribution du composite à la résistance à l'effort tranchant en relation avec les équations actuelles de la norme canadienne et des autres guides. Sur la base de cette analyse et des récentes avancées en recherche, des perspectives pour l'élaboration d'un nouveau modèle de calcul normatif et évolutif permettant de prédire la déformation effective et donc la contribution du composite à base de polymère renforcé de fibres (PRF) tenant compte des paramètres majeurs, dont l'armature transversale en acier, sont énoncées. Ce modèle sera ultimement intégré à la norme ACNOR S806.

- by Amir Mofidi
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- Adhesive, Composite Material, Cracking, Shear Force

We use the first-order shear deformation plate theory (FSDT) to analyze stresses in two layers bonded together with an adhesive as recommended by the ASTM D3165 standard, except that we also include a void within the adhesive. Depending upon the number of notches and voids, the specimen is divided into several regions. Assuming that a plane strain state of deformation prevails in the specimen, we write the balance of forces and moments for each section and impose the continuity of displacements, forces and moments at the interfaces between the adjoining sections. By taking the Laplace transform of the resulting ordinary differential equations we get a system of simultaneous linear algebraic equations that can be easily solved. The inverse transform of the solution of the algebraic equations provides stresses and displacements in the adhesive and the substrates, which are found to agree well with those obtained by the finite element method (FEM). It is also found that the order of the stress singularity at the corner of the free surface of the adhesive and the substrate, and the strain energy release rate computed from the solution of the problem with the FSDT agree well with those determined from the solution of the problem by the FEM. We note that the computational effort required to analyze the problem with the FSDT is considerably less than that needed to solve the problem by the FEM.

- by Romesh Batra
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- Materials Engineering, Mechanical Engineering, Chemical Engineering, Modeling

Two-dimensional (plane-stress and plane-strain) theoretical models are presented for stress analysis of adhesively bonded single-lap composite joints subjected to either thermal or mechanical loading or a combination thereof. The joints consist of similar/dissimilar orthotropic or isotropic adherends and an isotropic adhesive interlayer. The governing differential equation of the problem is obtained using a variational method which minimizes the complementary strain energy in the bonded assembly. In this formulation, through-thickness variation of shear and peel stresses in the interlayer is considered. Both shear and normal tractionfree boundary conditions are exactly satisfied. Peel and shear stresses obtained from plane-strain analytical models considering a homogeneous adhesive interlayer are in close agreement with those of the finite element predictions. A systematic parametric study is also conducted to identify an ideal set of geometric and material parameters for the optimal design of single-lap composite joints.

- by Siddharth Tampi
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- Composites, Composite Materials, Adhesive, Single Lap Composite Joints

Novel monomers 2-(N-methylacrylamido)ethylphosphonic acid, 6-(Nmethylacrylamido)hexylphosphonic acid, 10-(N-methylacrylamido)decylphosphonic acid, and 4-(N-methylacrylamidomethyl)benzylphosphonic acid have been prepared in good yields for use in dental adhesives. They have been fully characterized by 1 H-NMR, 13 C-NMR, 31 P-NMR, and by HRMS. All monomers are hydrolytically stable in aqueous solution. Free radical homopolymerizations of these monomers have been carried out in solution of ethanol/water (2.5/1:v/v), using 2,2 0 -azo(2-methylpropionamidine) dihydrochloride (AMPAHC) as initiator. They lead to homopolymers in moderate to excellent yields. Structure of the polymers has been confirmed by SEC/ MALLS and 1 H-NMR spectra. The photopolymerization behavior of the synthesized monomers with N,N 0 -diethyl-1,3-bis(acrylamido)propane has been investigated by DSC. New self-etch primers, based on these acrylamide monomers, have been formulated. Dentin shear bond strength measurements have shown that primers based on (N-methylacrylamido)alkylphosphonic acids assure a strong bond between the tooth substance and a dental composite. Moreover, the monomer with the longest spacer group provides the highest shear bond strength. V V C 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7074-7090, 2008

- by Wayne Cook
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- Materials Engineering, Photopolymerization, Adhesive, Polymer

Cellulose pulp, mainly utilized as a support for cleaning stone material, in this study, is proposed as a filler for wooden supports. In the last 10 years, pulp has been used in many restoration works carried out in the laboratory of the Diocesan Museum (MDP) in Palermo, including both wooden sculptures and panel paintings. These artworks, exhibited in the MDP, are constantly monitored in order to evaluate the effectiveness of cellulose pulp as a filler, assessing its durability and bio-receptivity. In particular, struc-tural characteristics, drying time, shrinkage, loss in weight, affinity to the pigments, etc., were simultaneously evaluated. Tests were also carried out on artificially aged cellulose pulp samples, in order to appraise if cellulose could be a source of nourish-ment for microbial growth.

- by Mauro Sebastianelli and +2
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- Cultural Studies, Art History, Art, Art Theory

The interface produced between a chlorinated thermoplastic styrene-butadiene-styrene rubber and a polychloroprene (PCP) adhesive has been studied and compared to the interface produced using a polyurethane (PU) adhesive. Chlorination of the rubber was produced by spin coating solutions of trichloroisocyanuric acid in methyl ethyl ketone. The adhesive solution was spin coated on to the chlorinated rubber and the interface between the chlorinated rubber and the adhesive was analyzed by infrared spectroscopy.Chlorination of the rubber produces cross-linking of the outermost chlorinated and oxidized rubber surface, which becomes insoluble in toluene. The chlorinated rubber chains are able to migrate through the chlorinated rubber/adhesive interface and produce a cross-linked interface. Similar interfaces are obtained with PU or PCP adhesive. However it is the addition of a thermoreactive phenolic tackifier resin to the PCP adhesive, which imparts appropriate rheological properties to the PCP adhesive, responsible for the increased adhesion properties. Copyright © 2008 John Wiley & Sons, Ltd.

- by Mercedes Pastor Blas
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- Condensed Matter Physics, Collagen Cross-linking, Adhesion, Adhesive

The influence of environmental conditions, in particular temperature, on the performance of adhesives joining different archaeological ceramic fabrics is assessed in laboratory conditions. Different types of model ceramic fabrics were manufactured and joined with commercially available adhesives, which are commonly employed in the conservation of archaeological ceramics, and a series of systematic tests on the various adhesive–ceramic systems was conducted. The response of joins to static mechanical stress was assessed in controlled loading tests. Results of those tests as well as failure mechanisms observed are discussed.

- by Konstantinos Alexiou and +3
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- Pottery (Archaeology), Mechanical Properties of Ceramics, Fracture, Ceramics (Archaeology)

Based on Schiff base chemistry, crosslinked porous organic aminal networks were prepared using acetic acid as a catalyst. These Schiff base networks (SNWs) are polymeric materials based on melamine and 5,5′-methylene-bissalicylaldehyde, with nitrogen contents as high as ca. 36 wt.%, which were characterized by FTIR spectroscopy, elemental analysis, and 13 C and 15 N solid-state NMR spectroscopies. A series of polymer networks with different monomeric molar ratios and different amounts of added catalyst were explored, in order to study their effect on the final polymer structure, porosity and H 2 storage capacity. These materials exhibit Brunauer-Emmett-Teller (BET) surface areas up to ca. 526 m 2 /g, as measured by N 2 adsorption at 77 K, and exhibit gravimetric storage capacities up to 2.57 wt.% at 20 bar and 77 K. Keywords Aminal networks . Hydrogen storage . Melamine-based networks . Porous polymers . Schiff base networks Electronic supplementary material The online version of this article (

- by Ayman Atta and +1
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- Engineering, Materials Engineering, Adhesive, Polymer

The hafting of tools using adhesive is one of the innovative features that characterizes the southern African Middle Stone Age. This technology has mainstream implications but remains insufficiently documented, largely due to unequal organic preservation and non-adapted analytical procedures. A notable exception is provided by the recent results from the site of Sibudu .

- by Armelle Charrié (-Duhaut)
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- Archaeology, Geochemistry, Technology, Archaeological Science

The current paper presents research aiming at characterizing the fatigue behaviour of adhesively bonded joints. In this study, a new mathematical model to predict fatigue crack propagation rates for adhesively bonded joints has been investigated and presented. The proposed method uses fatigue test data and stiffness data obtained from finite element model of bonded joints. T-peel and single lap shear bonded joints were prepared using aluminium alloy AA5754 and Betamate epoxy adhesive 4601. The fatigue tests were conducted using constant amplitude loading using an R ratio of 0.1 at a frequency of 10 Hz. The FE models used in this work were developed using fracture mechanics tools in Abaqus. The results were post processed to extract energy release rates in form of J Integrals and stress intensity factors. The stiffness results obtained from both experimental testing and numerical studies were combined using appropriate curve fitting models proposed in the literature to estimate the fatigue crack propagation rates and obtained the de-bond curves in the Paris regime for such joints. The crack growth rates were further modelled and validated using neural network technique in MATLAB.

- by Applied Engineering Letters and +1
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- Engineering, Mechanical Engineering, Finite Element Methods, Finite Elements methods