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In this study, the shear strength and thermal properties of the adhesively bonded joints were investigated of adhesives reinforced with nanoparticles using carbon fiber-reinforced composite materials. The diglycidyl ether bisphenol A (DGEBA) was used as the epoxy resin. Single lap joint tests of 1% wt. Multi-walled carbon nanotubes (MWCNT) and 3, 5, and 7% wt. silicon dioxide (SiO2) nanoparticle-reinforced mixed adhesives were performed according to ASTM D5868 standards. The shear strengths of the mixed adhesives obtained by mixing at different ratios were compared with the epoxy resin. Upon conducting an analysis of the shear strengths of nanomaterials, results indicate that the incorporation of 1CNT + 3SiO2 in the nanomaterials showed the greatest improvement, with a 46% increase in shear strength. 1CNT + 5SiO2, 1CNT, and 1CNT + 7SiO2 showed increases of 32%, 14%, and 5%, respectively. The results of a tensile test indicate that pure epoxy exhibited a tensile strength of 5953 N, 1CNT, and 3SiO2, while the epoxy composite demonstrated a significantly higher tensile strength of 8738 N, along with an elongation of 0.72 mm. In addition, the morphology of fractured surfaces was examined by scanning electron microscopy (SEM). To investigate damage mechanisms, such as bridging, crack blunting, and branching of nanoparticles were observed. Characterization of epoxy resin and mixed MWCNT + SiO2 nanoparticles reinforced adhesives were also performed using Fourier infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). Nanoparticles are settled between polymer chains, improving polymer chains' motion and thermal properties. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the synthesis and characterization of an adhesive based on a glucose stabilized polyvinyl acetate homopolymer. Vinyl acetate monomer was stabilised onto liquid glucose using emulsion polymerization, and polymerization happened using potassium persulfate as an initiator. Here, the effects of adding liquid glucose as a stabiliser for adhesives were studied. Therefore, the current research examines whether liquid glucose, introduced at weight-based concentrations of 0.5% and 1.0%, is suitable as a colloid to produce PVAc adhesives for wood. By measuring viscosity, pH, contact angle, differential scanning calorimetry (DSC), and the pencil hardness test of films, the effect of adding liquid glucose as a colloid on physical, thermal, and mechanical properties was investigated. The shear strength of the PVAc homopolymers applied to wood using emulsions with varied liquid glucose concentrations was measured using a universal tensile machine. As the concentration of liquid glucose increased, the viscosity of the adhesives also considerably increased. Water resistance significantly rose when liquid glucose content increased, as was found by measuring the water contact angle. The use of liquid glucose increased the hardness of PVAc films, which was supported by the glass transition temperature. According to EN 204-205, the tensile shear strength with 1.0% of liquid glucose increased by 63.88% and 45.67%, respectively, over a pristine sample after 6 h of bonding in a dry environment and 24 h in a wet environment. The study's overall conclusion highlights the higher adhesion capability of PVAc emulsion-based adhesives stabilized by liquid glucose. [ABSTRACT FROM AUTHOR]

Starch is one of the oldest adhesives, and has been utilised for a variety of applications, including as a consolidant for artworks and archives, after cooking. Although widely available, cost-effective, and versatile it has limitations such as large particle size, which makes it challenging for the adhesive to penetrate deeply into objects. Attempts to increase the concentration of starch adhesives for enhanced strength often lead to increased viscosity, hindering penetration and causing an undesirable film on the surface. Achieving a workable consistency often leads to reduced adhesive power. An approach to using nanosized starch as a binder for paper and cellulose-based objects is presented. Starch nanoparticles (SNPs) from wheat, rice, maize and waxy maize were successfully synthesised using a 'top-down' approach that is facile as well as energy efficient. Size distribution measurements indicate most particles to be less than 50 nm, smaller than the pore size of most historic papers. SNPs could make a better sizing adhesive than traditionally-made starch paste, and they are also a green alternative to a variety of chemically formulated, organic solvent-based adhesives. The compatibility, non-toxicity, and biodegradability of starch remained uncompromised during the modification. [ABSTRACT FROM AUTHOR]

This paper outlines a research project on the use of wood tar as adhesive for architectural stone repairs. Tar was identified as having been used in medieval repair techniques on Stavanger cathedral in Norway, as well as on several other medieval cathedrals in England and Germany. The hypothesis is that a complex adhesive mixture based on wood tar was manufactured and strategically employed by medieval artisans in northern Europe as stone repair material. Given that such repairs have withstood centuries of wear, there must have been extensive material knowledge and awareness of the complex requirements of structural adhesives. These historic tar repairs created the impetus for a research project, the aim of which is to rediscover the lost medieval art of traditional stone repair using wood tar adhesives, recreate the historic adhesive and repurpose it for modern conservation practice. By reintroducing traditional wood tar adhesives based on natural renewable source materials, we could potentially reduce dependence on synthetically manufactured adhesives. Thus, newly-discovered medieval techniques which have successfully lasted centuries will be drawn on to help solve the limited selection of suitable adhesives for stone conservation, contributing to future preservation of stone architecture and the built heritage environment. [ABSTRACT FROM AUTHOR]

This study shows that the progressive adhesion of weld material to the tool in friction stir welding AA 2024-T3, up to tool saturation, brings about a decrease in power consumption until a plateau is reached. The cause of this behavior is the hindering of the stirring action of the tool due to the material accumulated on it. The built-up material changes the nature of the tool/material interaction and then the friction condition at their interface. The direct consequence is a decrease in the shearing strain and therefore in the heat generated by friction. Bits of this adhering material break off from the tool at intervals. Macro and micro detachments are identified. Micro-detachments happen continuously at small periodic intervals and produce vibrations. The amplitude of these vibrations increases in all their characteristic spectral components up to tool saturation. Macro-detachments generate oscillations in power consumption and leave galling on the weld bead. [ABSTRACT FROM AUTHOR]

This study evaluated improvements in the micro-tensile bond strength of a one-bottle adhesive to dentin upon incorporating a thiol compound. Formulations containing 0, 0.1, 0.3 or 0.5% of the thiol were prepared (TH78-0, TH78-0.1, TH78-0.3 and TH78-0.5). Flat dentin surfaces were produced on non-carious extracted human molars using a diamond saw and 600 grit SiC paper. Each surface was subsequently treated with one of the four experimental adhesives or a commercially available adhesive (Scotchbond Universal Adhesive), following the manufacturers' instructions. A resin composite was then incrementally built on the adhesive-treated surfaces and light-cured, after which the bonded specimens were sectioned and subjected to micro-tensile bond strength tests. Bond strengths ranging from 28.7 MPa (for the TH78-0.5) to 45.9 MPa (for the TH78-0.1) were obtained from the experimental specimens, whereas the commercial adhesive showed a strength of 36.9 MPa. A 0.1% thiol concentration therefore increased the baseline bonding of the adhesive and gave the highest strength, with significantly decreased values in the cases of 0.3% and 0.5% concentrations. [ABSTRACT FROM AUTHOR]

AbstractStudying the mechanical responses of GFRP and aluminum samples under varying loads is crucial for developing methods to enhance their mechanical properties. This research investigates the impact of z-pinning on single-lap adhesive joints through low-velocity shear impact tests. The study involves testing two types of joints: single-lap adhesive joints and single-lap hybrid pin-adhesive joints with six reinforcing pins, subjected to drop weight tests at load levels of 22.5, 27.5, and 32.4 J. The findings demonstrate that z-pinning can increase the joints’ load-bearing capacity by up to 18.87% and energy absorption by 20.58%. This enhancement is attributed to the additional composite substrate layers in the hybrid joint, which help absorb impact loads. In contrast, in the single-lap adhesive joint, only the layer adjacent to the adhesive bears the impact load. Observations from the tests indicate that in the single-lap adhesive joint, the first composite layer next to the adhesive undergoes complete delamination, whereas in the hybrid joint, all laminates fracture at the steel pins. In summary, this study underscores the significant potential of z-pinning to improve single-lap adhesive joints, providing an innovative approach to enhance their load-bearing capacity and energy absorption. [ABSTRACT FROM AUTHOR]

Chitosan is a polysaccharide resulting from chitin deacetylation. It has demonstrated interesting characteristics in the field of adhesion but loses most of its adhesive resistance in moist environment. A chemical crosslinking of chitosan with genipin has been implemented to improve its adhesive properties in the presence of water. The study of crosslinking kinetics using rheology revealed its dependency on crosslinking rate and chitosan concentration. The capacity of the chitosan-genipin systems for water absorption has been quantified as their Free Swelling Capacity. The cross-linkage of chitosan by genipin (1% w/w) decreased significantly its ability for water absorption. Finally, the adhesive strength of several chitosans be they supplemented or not with genipin and/or glycerol used as plasticizer have been performed on Thick Adherent Shear Test samples of beech wood according to standard EN 204:2016 and EN 205:2016. The chitosan adhesive formulation containing genipin and glycerol exhibits the better adhesive properties on wood and presents higher water resistance compared to the native chitosan formulation. [ABSTRACT FROM AUTHOR]

Amongst water-based emulsion adhesives, polyvinyl acetate (PVAc) emulsion is majorly employed in the non-structural bonding of interior or exterior furniture and joinery industries. However, PVAc emulsion requires plasticizers, which inherently have challenges resulting in deteriorating thermal and mechanical properties. Hence, the present work focuses on formulating a plasticizer-free adhesive by copolymerizing vinyl acetate with butyl acrylate (BA). The physical, thermal, and mechanical properties of BA-incorporated adhesives were analyzed by viscosity, pH, water contact angle, pencil hardness test of films, and differential scanning calorimetry. Optimizing strategy by varying the content of BA was evaluated. The shear strength of the samples on the wood specimen was verified in dry conditions at various intervals, and in wet conditions as per EN 204 standard. The viscosity of the adhesives exhibited a positive shift, as the concentration BA increased. The hardness of PVAc films was also altered positively by the addition of BA. Water contact angle measurement unveiled the hydrophobic nature of BA incorporation. The performance of the newly formulated adhesive tested on dry conditions showed enhanced tensile shear strength, and the values were maximum for 1 wt. % BA sample. Tensile shear strength value measured at dry conditions after 7 d of drying displayed an increment of ∼5.5% on 1 wt. % BA sample, compared to pristine adhesive. Analysis at wet conditions also corroborated enhanced performance with BA incorporation. Hence by optimizing the content of BA, a new concept of PVAc emulsion adhesive without any plasticizer can be formulated, with enhanced water resistance and performance. [ABSTRACT FROM AUTHOR]

Phenol-formaldehyde (PF) resin is a common adhesive in the plywood industry with the main advantage of its water resistance and high bonding strength. However, PF has unfavorable high curing temperatures which becomes of cost concern. In the present work, sodium silicate was used to modify the resin properties to lower its curing temperature. The amount of sodium silicate was varied in a range of 0% to 25% (w/w) in terms of sodium silicate to phenol. The thermal properties of the modified resin and its bonding strength were investigated. The experimental result showed that the presence of sodium silicate can increase crosslink density which leads to higher bonding strength. In addition, the presence of sodium silicate resulted in a lower curing temperature and reduced curing activation energy. The addition of 25% (w/w) sodium silicate could increase the bonding strength by more than 200% and decrease the curing temperature by about 35 °C. The improved processability and energy consumption offer advantages for the effective application of phenol-formaldehyde, particularly in the wood industry. [ABSTRACT FROM AUTHOR]

In the rapidly developing microelectronics industry and technology, epoxy resin based electrically conductive adhesives must be urgently improved in terms of aging resistance, especially residual stress caused by thermal cycle aging. In this study, we investigated the stress behavior of rigid and flexible epoxy systems blended with bisphenol F epoxy (BPF) and fatty acid epoxy. The curing processes, thermal, and thermomechanical properties of the modified epoxy systems were assessed comprehensively. Moreover, the residual stress during the thermal cycle was monitored, and the bond strength was characterized. The results pointed out that by introducing soft molecular segments into a rigid system, the modified epoxy resin system had significantly lower residual stress values and exhibited a higher bond strength over a wider temperature range. Finally, we envision the systematic integration of residual stress testing with material strength testing for quantifying the bond failure of adhesive layers in the near future. [ABSTRACT FROM AUTHOR]

In recent decades, due to high market demand and multiple environmental concerns, attention has been focused on the use of starch as renewable raw material for adhesives elaboration. Particularly, the origin and film-forming properties of Achira (Canna edulis) starch make it a potential representative for the development of bioadhesives. In this study, achira starch modified by acid hydrolysis and subsequent derivatization with urea was used to prepare adhesives for plywood substrates. For this purpose, the modified starch and polyvinyl alcohol (PVA) were used to prepare several formulations with different proportions of components. Afterwards, they were characterized in terms of physicochemical and mechanical properties. The formation of starch carbamates was confirmed not only by the results of nitrogen content, but also by infrared spectroscopy through the presence of N-H and C=O groups. On the other hand, viscosity increased with PVA content due to the interaction of hydroxyl groups, while starch had the opposite effect. Shear strength showed higher values at higher concentrations of PVA and starch. From the perspective of mechanical behavior, the results showed similarities with a commercial adhesive based on polyvinyl acetate (PVAc), as well as with other bio-based adhesives from studies conducted under comparable conditions. [ABSTRACT FROM AUTHOR]

AbstractThis article aims to investigate the effect of elevated temperature on the fatigue performance of CFRP-reinforced cracked steel plates and optimize the design parameters for their reinforcement. Based on the self-developed adhesive GY34, a finite element model of the CFRP-reinforced central cracked steel plate is established by the ABAQUS software. Parametric analysis is carried out on different bonding methods of CFRP plates and different thicknesses of adhesive layers for CFRP-reinforced cracked steel plates. The effect of elevated temperature on the reinforcement is also studied to verify the excellent performance of GY34 adhesive. Furthermore, the enhancement of fatigue life for cracked steel plates reinforced with CFRP plates at different temperatures is investigated using the Paris model and modified Newman model. The results show that double-sided reinforcement with CFRP is more effective than single-sided reinforcement. All of the different bonding methods could reduce effectively the stress intensity factor of cracked steel plates and improve significantly the bearing capacity of the steel plates. Among them, increasing the number of CFRP layers and their elastic modulus yield the most significant improvement on the reinforcing effect. Elevated temperatures effect greatly on the mechanical properties of adhesively bonded CFRP-reinforced steel plates. The effective bonding length and the stress intensity factor amplitude at the crack tip of the steel plate increases with temperature rises, which may accelerate the growth rate of fatigue crack and reduce the reinforcing effect on fatigue life. [ABSTRACT FROM AUTHOR]

In this paper, the effect of adding Single-Walled Carbon Nanotubes (SWCNT) and Fullerene Nano particles to the adhesive of Carbone fiber reinforced plastics (CFRP) single lap joint (SLJ) has been investigated on the lap shear strength of the joint both before and after the applying of the hygrothermal conditions. Different SLJ samples were manufactured containing different percentages (0–5% Vf) of SWCNT, Fullerene and a mixture of both that was designed using Responsive Surface Method (RSM). Hygrothermal conditions of 70 ° C temperature and humidity of 100% was then applied to the samples for the duration of 2 weeks after which, the tensile (lap shear) strengths of the un-aged and aged samples along with the amount of moisture absorption and failure surface of SLJs were measured and compared. The results showed that addition of particles, especially Fullerene decreases water absorption, resulting into increase in the lap shear strength of the SLJ. Hygrothermal conditions decreased the strength in neat adhesive, SWCNT and Fullerene reinforced samples but it increased in the samples with adhesive having mixture of Fullerene and SWCNT. The failure mode of the SLJs were combination of adhesive and cohesive where the hygrothermal condition and addition of the particles increased the area of the cohesive failure zone. Finally it was observed that, the optimum sample has 2.25% Vf of mixture of both SWCNT and Fullerene with lap shear strength 7% higher than the neat adhesive SLJ before hygrothermal aging and 31% after applying of the hygrothermal aging. [ABSTRACT FROM AUTHOR]

The existing studies on the degradation mechanism of composite adhesive joints mostly focus on the aging of adhesives, but the aging effect of composites is often ignored. In this paper, the degradation mechanism of adhesive, CFRP, as well as shear joints (SJ) and butt joints (BJ) in thermal-humidity-cycles (T-H-C) for automobiles were investigated by chemical detection and mechanical testing. The aging effects of adhesives and composites are compared and analyzed by the variation in chemical and mechanical properties to reveal the degradation mechanism of composite adhesive joints. Experimental testing show that the adhesive and CFRP underwent hydrolysis and oxidative decomposition respectively, and there was a reduction in Tg (glass transition temperature) and thermal stability. The joint strength of composite adhesive joints fell by around 40% after 30d (days), and interfacial failure appeared. The variation in the composition of adhesive and CFRP, interfacial failure and thermal stress contributed to the degradation of composite adhesive joints. Degradation mechanism analysis shows that SJ under shear stress state were less affected by CFRP aging, while BJ under normal stress state were more affected by CFRP aging and the effect became more obvious with time growth. [ABSTRACT FROM AUTHOR]

Abstract This study introduces an innovative numerical approach, validated through experiments, to incorporate functional graded materials (FGMs) volume fractions into mixing laws for fiber–matrix unidirectional composites. Nonlinear techniques address adhesive ductility, with the cohesive zone modelling (CZM) model integrated into finite element analysis using the ABAQUS code. The CZM model encompasses shear and detachment modes, characterized by adhesive stress increase in a trapezoidal shape. Proposed strategies introduce layer-specific fiber presence; concepts like C-1 exhibit denser fibers toward the middle, while C-2 and C-3 position them nearer to the plate edge. Stiffness from attached plates significantly governs overall responses, particularly under mixed loading conditions. The results have shown that the proposed grading concept C-2 provides an over-resistance capacity compared to other concepts. Additionally, using a special mesh in the composite grading, the results indicate that the adhesive formulation used in this analysis and the approach followed are primarily based on experimental results, demonstrating good agreement with the numerical model employed. [ABSTRACT FROM AUTHOR]

Prediction of stresses in adhesively bonded joints requires high effort in determination of relevant material properties, which change during cure. In addition, the computational effort using complex viscoelastic finite element (FE) models impends efficient prediction of stress build-up. Rotational and oscillatory rheometry can help to reduce the experimental effort by measuring of modulus of elasticity (MoE) and axial shrinkage along curing. In this publication, shrinkage, development of MoE and Poisson's ratio of a curing adhesive were numerically modelled between two parallel rheometer plates in order to calculate cure-induced stresses using finite element analysis (FEA). To identify effects of different material properties on stress distribution, a parameter study was carried out and the reciprocal influence of the varied parameters was investigated. Consequently, resulting stresses within the adhesive layer and occurring deformations were investigated with respect to curing time as well as their location. The results showed that final shrinkage and MoE need to be considered not only in final values but also in terms of course of shrinkage and reaction. Stress build-up led to deformation of the rheometer plates, which has to be considered when using rheometry for determination of cure shrinkage. [ABSTRACT FROM AUTHOR]

In this study, single lap shear experiments with Al2024-T3 substrates were used to evaluate poly(dicyclopentadiene) (pDCPD) for structural adhesive applications. A wide range of monomer-to-catalyst ratios (M:C = 10,000:1 to 90,000:1) and four different silane coupling agents (i.e. hexyl, hexenyl, allyl, and norbornyl trimethoxysilane) were used to understand their effects on the adhesive shear properties of pDCPD. The roles of pDCPD oxidation and the bulk polymer on adhesive properties were also investigated using paint and dynamic mechanical analysis (DMA) measurements. Collectively, the data show that the choice of silane has a significant influence on the lap shear strengths of pDCPD, while the M:C ratio has a smaller but significant influence. Differences in bulk polymer topology as measured by DMA and oxidation of the resin had insignificant effects in the absence of exposed oxygen-rich surfaces that influence catalyst activity. With shear strengths up to 21.6 ± 0.7 MPa for dry conditions and up to 13.0 ± 0.7 MPa for hot-wet conditions (i.e. submersion in deionized water at 60 °C for 2 weeks), we showed that pDCPD-based adhesives have comparable lap shear properties to a well-studied model thermoset epoxy (i.e. DGBA/D230). [ABSTRACT FROM AUTHOR]

This study aimed to investigate the possibility that a calcium phosphate ion cluster (CPIC)-incorporating phosphoric acid (PA) solution promotes the remineralization of the hybrid layer and prevents nanoleakage from the dentin–resin interface, thereby minimizing dentin–resin bond failure during long-term bonding periods. The specimens were prepared using human molars and treated with three types of etching solutions (35% PA, and CPIC-incorporated PA solutions at 1:1 and 1:2 ratios). The microtensile bond strength (µTBS) of half of the specimens was measured after 24 h, and measured after thermocycling for the other half. Fourier-transform infrared spectroscopy (FTIR) was performed to chemically analyze the remineralization, and the degree of nanoleakage in each sample was observed using a scanning electron microscope (SEM). The CPIC-incorporated PA-II solution decreased the nanoleakage in the hybrid layer without reducing the µTBS, with or without thermocycling, and promoted remineralization of dentin collagen. [ABSTRACT FROM AUTHOR]

Synchrotron radiation (SR)-based soft X-ray (SX) microspectroscopy has been applied as a promising analytical method to investigate architectural structures that comprise ceramic-tile/adhesive/mortar-structured composite materials. Microprobe X-ray fluorescence (µXRF) spectra, elemental distribution maps and microprobe near-edge X-ray absorption fine structure (µNEXAFS) spectra were observed near each interface in the composite materials using an SX-beam with a beam size of 1–2 µm full-width at half-maximum (FWHM). Elemental distribution maps for O, Na, Mg, Al, and Si were obtained to clearly visualize the interfaces of the composite materials with pixel sizes of 10 and 1 µm with the aid of line profile analyses. When the photon flux of the focused SX-beam reached approximately 8 × 108 ph/s, the critical dose time ( t dose c ) for the adhesive was estimated to be 30 min ( t dose c is the time at which the peak intensity of a specific chemical state in the µNEXAFS spectrum decreases to 1/e of the initial undamaged state due to radiation damage). We demonstrated the capability of the proposed method to survey local information regarding element-specific chemical states at the ceramic-tile/adhesive and adhesive/mortar interfaces before the adhesive is severely damaged due to the intense SX-beam. [ABSTRACT FROM AUTHOR]

Dry and hot/wet lap shear specimens were prepared and tested to evaluate catechol-containing additives in a model epoxy adhesive. We specifically compared adding neutral dopamine, which is capable of being covalently incorporated into the epoxy network, with molecular analogues that contain methyl, methoxy and fluorine rather than hydroxyl groups. We found that catechol was unique among these additives in improving both dry and hot/wet lap shear strength. While neutral dopamine can only be added to relatively low concentrations due to solubility limitations, other catechol-containing polymers and monomers based on maleimide also showed increases in dry and hot/wet lap shear strength upon incorporation. Dynamic mechanical analysis measurements suggested that the differences observed were not likely due to differences in either polymer mechanical properties or polymer topology. [ABSTRACT FROM AUTHOR]

The mechanical strength of wood-based products (WBP) is determined by the anatomical structure of wood, including the specificities of earlywood (EW) and latewood (LW), and the bonding interphase between wood and adhesive. In this study, two-layered specimens were manufactured according to three possible assembling strategies in terms of the anatomical structure of wood. Wood micro-structure and phenol formaldehyde (PF) adhesive distribution were visualized with optical and fluorescence microscopy. Internal structure changes were dynamically monitored using X-ray computed micro-tomography (X-ray µCT) while compressing specimens. The results showed that in EW, adhesive could penetrate into cell lumens through collapsed cell walls. In LW, an adhesive can diffuse along rays. In bonding interphase, consisting of EW and LW, an adhesive preferably penetrates into EW. The adhesive increases EW stiffness but has little impact on the stiffness of LW.EW was mainly compressed during compression due to the collapse of the thinner cell walls and larger lumina. The collapse of the cell walls was more likely to happen in regions close and parallel to the boundary of growth rings. The cell structure in adjacent areas to resin ducts of LW was more affected, as these can be squeezed under compression. [ABSTRACT FROM AUTHOR]

The concept of multi-material design has been applied in many industries in recent years. Among various methods of joining dissimilar materials, adhesive bonding has the advantage of being low weight. It is necessary to understand the failure criteria of adhesives in choosing the most preferable adhesive for improving the strength of a bonded structure. Experiments using pipe specimens with inclined surfaces bonded by epoxy adhesive were performed, whereby multiaxial stress states were realized simply by conducting a uniaxial tensile test. The failure function of the epoxy adhesive, expressed by the mean stress and octahedral shear stress, was then obtained from the experimental data and compared with that of acrylic adhesive previously reported in the literature. The obtained failure functions of both adhesives were then applied to the shape optimization of the adhesive layer under different loading conditions. The optimization object is the strengthening of bonded structures. The optimal shape for different loading conditions differed for the different adhesives because of the driving force generated by the applied stress. The final shapes were thus optimized numerically to attain the highest mechanical integrity of the adhesive layer and found to be strongly dependent on the initial shapes before optimization. [ABSTRACT FROM AUTHOR]

In recent years, aluminium alloy became an emerging construction material. In order to repair or strengthen the wood beam with an appropriate material, six timber beams reinforced with different thicknesses of aluminium plates and connections between the timber beams and aluminium plates were tested in this article. To investigate the ultimate bending capacity of timber beams which were reinforced using the aluminium plates with the thicknesses of 3 mm and 8 mm, the influences of adhesive, screw, adhesive and screw on the beading capacities are studied. The ultimate bending capacity of timber beams reinforced using the aluminium plates with the thicknesses of 3 mm and 8 mm was investigated. Three plain timber beams were also tested for the comparison. An analytical model has been developed for predicting the ultimate bending capacity of the timber beam reinforced with aluminium plate by using the adhesive and screw together connection. The results indicate that the initial bending stiffness and ultimate bending capacity of the reinforced timber beams can be enhanced obviously. Compared with the beams without reinforcement, the initial bending secant stiffness of the beams reinforced with aluminium plate was enhanced by 109% maximally and the average increase was 55%. The ultimate bending capacities of the beams reinforced with aluminium plate were enhanced by 57% maximally and the average increase was 30%. The most effective way to enhance the ultimate bending capacity of the reinforced timber beam is to use the adhesive and screw together connection. The strain distributions along cross section of the timber part of the reinforced beam were approximately linear. [ABSTRACT FROM AUTHOR]

It is an effective way to utilize low-rank coal to obtain Hyper-coal by thermal extraction. Taking Shanxi lignite as raw material, the Hyper-coal was obtained by extraction at several temperatures. The basis of Hyper-coal as an excellent upgrading binder for coking was comprehensively studied from two aspects of macrocohesion index and microstructure. The experimental results show that the content of ash and sulfur in the Hyper-coal is low, and the content of light components is increasing with the increase of extraction temperature. The thermoplasticity of hyper-coal is generally high, the fluidity of colloid formed by pyrolysis is higher than that of conventional coking coal, and the bonding ability also reaches the level of fat coal. The source of high thermoplasticity of hyper-coal mainly depends on its microstructure, such as high aliphatic hydrocarbon content and wide thin compact carbon network structure. The optimum extraction temperature was 380°C. Generally speaking, Hyper-coal can be used as an excellent binder for coking. [ABSTRACT FROM AUTHOR]

This publication presents a novel in-situ method, which combines a rotational rheometer and optical measurement of the sample geometry for accurate determination of volume shrinkage. The presented method includes shrinkage measurements in the rotational rheometer with simultaneous observation of the specimen's meniscus by a laser distance sensor. The combination enables detection of time-dependent dimensional changes in axial and lateral direction. Therefore, volumetric shrinkage can be detected accurately in a rheometer for the first time. To establish the methodology, measurements were carried out on two non-curing resin components. For validation, experiments with constant volume at different gap sizes were carried out. Results indicate that the accuracy of the method enables the measurement of shrinkage of reactive adhesives. For a translucent adhesive or resin, it was also shown that the penetration behaviour of the light can be taken into account when evaluating the results. Subsequently, the extension of a rotational rheometer by an optical distance measurement allowed evaluation of volume shrinkage for a 2-component epoxy by tracking changes in the axial gap and of the meniscus (lateral shrinkage) for two testing scenarios. This approach extends and improves previous methods that only determine the volume shrinkage by tracking the plates of a rheometer. Furthermore, trim gaps and other edge effects may be taken into account as well, focussing on their deviation from the otherwise assumed cylindrical shape. [ABSTRACT FROM AUTHOR]

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Failure tests for internal pressurized composite pipe system joined by using different radii pipes were carried out by the finite element method and experimental tests. The composite pipes were produced from E glass fiber/epoxy. DP410 and DP490 type adhesives were used to join the composite pipes. The numerical results and experimental results were compared. It was shown that the numerical analyzes results were close to experimental results. Tangential, radial, axial, and shear stress values on composite pipes and adhesive layers were obtained via numerical analyses in the radial direction. Additionally, the von Mises stress distributions were obtained on the adhesive. The effects of adhesive layer lengths, adhesives types, and orientation angle on the effect of the joint zone were investigated. [ABSTRACT FROM AUTHOR]

Under the condition of high-stress abrasive wear, the strength at the interface of the WC/Fe matrix composites is significantly low, it is very easy to become the source of the overall damage to the material. In this study, the mechanical properties and interfacial organization of the WC/Fe matrix composites were analyzed by adding a binder and using a combination of powder metallurgy and gravity casting infiltration. The results showed that upon the addition of an adhesive, the width of the interface became twice as large as that without additives. Moreover, adding an adhesive also reduced the plastic deformation at the interface by more than three times. The best bonding agent was borax + sodium carbonate, which significantly increased the diffusion rate of atoms at the interface compared to sodium silicate and polyvinyl alcohol and also enhanced the interfacial mechanical properties. [ABSTRACT FROM AUTHOR]

In this study, water-based polyurethane adhesives (WOPU) with excellent adhesion to thermoplastic polyolefines (TPOs) were synthesized. Polyester polyol and polyolefin polyol, 4,4'-dicyclohexylmethane diisocyanate, and isophorone diamine were used. The properties of the PU dispersion were evaluated by Fourier transfer infrared spectroscopy, differential scanning calorimetry, thermogravimetry and a universal testing machine. The effects of polyolefin polyol on the properties of the PU dispersion adhesives were systematically investigated. The PU dispersion showed highest tensile strength of 278 kgf/cm2 when the ratio of polyester polyols to polyolefin polyols was 9:1. The adhesion strength and water resistance showed the same trend. [ABSTRACT FROM AUTHOR]

This study aimed to systematically review the literature on laboratory researches and statistically determine the influence of mineralizing strategy on the dentin bond stability. The search was conducted in PubMed/MEDLINE, Web of Science, EMBASE, and SCOPUS according to the PRISM guidelines. From 2200 possible eligible articles, 50 were selected for full-text analysis, and 15 were included in the systematic review. Two authors independently selected the studies, extracted the data, and assessed the risk of bias. Bond strength analysis was conducted by RevMan5.3 with random effects model (α = 0.05), comparing control (without mineralizing strategy) and experimental groups (mineralizing strategy). Fifteen included trials concerned 46 comparisons between experimental groups adopting mineralizing strategy and control groups. Mineralization strategy reduced the dentin bond strength loss after aging. Although non-significant, the aging bond strength was higher than traditional bond methods (p = 0.07), the improvement was significant in pretreat (p = 0.01) and etch and rinse subgroup (p = 0.04). A significant reduction was found in immediate bond strength was associated with the use of mineralization strategy (p = 0.003). The majority of included studies were scored high risk of bias, high heterogeneity was presented in the meta-analyses. Mineralization strategy reduced the dentin bond strength loss after aging. Bond strength after aging tends to be increased by mineralization strategy when used as a pretreat procedure, and in etch and rinse adhesive system. However, the mineralization strategy reduced the immediate dentin bond strength and didn't influence aging bond strength in total. [ABSTRACT FROM AUTHOR]

In real-world applications, adhesive joints are often exposed to the environment and can experience cyclic ageing conditions caused. However, the adhesive response under cyclic ageing is still relatively unexplored. In this study, hygrothermal ageing of an epoxy-based adhesive has been investigated by performing single cycle and cyclic ageing experiments. Different cyclic ageing strategies were followed in this research. In the first strategy the ageing time was set to a constant value and in the second approach, the maximum absorbed water content was limited for each ageing cycle. Absorption and desorption processes for each ageing cycle have been analysed using Fick's law. This analysis allowed to determine the diffusion coefficients and assess how they are affected by cyclic ageing. Other parameters, such as the ability to absorb water, saturation time and the glass transition temperature were also studied as a function of the different ageing conditions. The experimental results of the cyclic ageing studies showed that the water diffusion process changes with ageing cycles. It was also found that the glass transition temperature decreases with ageing cycles. Numerical analysis was also conducted using Fick's law constants. Good agreement between the experimental and numerical results was obtained. [ABSTRACT FROM AUTHOR]

Steel plate-concrete joints are often applied in strengthening of engineering structures. Eighteen steel plate-concrete joints (connection length of 260–520 mm, width of 80 mm) were tested, which were classified into three types: (a) anchor-connected specimens (BC specimens), in which the steel plates and concrete were connected with anchors; (b) adhesive-connected specimens (AC specimens), in which the steel plates and concrete were connected with adhesive; (c) anchor- and adhesive-connected specimens (BAC specimens), in which the steel plates and concrete were connected with both anchors and adhesive. The following conclusions were drawn. (1) For the same connection length, the ultimate loads of the BAC specimens (e.g. 127 kN) were approximately 78% of the sum of those BC and AC specimens (e.g. 112 and 53 kN). (2) For the BAC specimens, almost all of the load was borne by the adhesive and the anchor hardly shared any load before the specimens reached the peak load. (3) A modified semi-theoretical and semi-empirical formula (C-T model) has been used, which was used to predict the ultimate load of the BAC and AC specimen with satisfactory precision. [ABSTRACT FROM AUTHOR]

For understanding the interactions between adhesives and different surfaces, the in-situ characterization of the interface is essential. Especially for highly reactive cyanoacrylates, better known as super glues, the adhesion mechanism is poorly understood because, among other things, the characterization of the interface is difficult. The aim of this work is to evaluate methods to produce nm-thin, homogeneous films of cyanoacrylate to enable spectroscopic analysis of the interface in the future. Two deposition techniques, thermal evaporation and spin coating, of ethyl-cyanoacrylate, are compared. Thickness and composition of the cured films are investigated by atomic force microscopy, laser scanning microscopy and x-ray photoelectron spectroscopy. Thermal evaporation in ultra-high vacuum leads to cluster-like depositions and is therefore not suitable for interface analysis. Spin coating is strongly dependent on solvent and concentration. While the solvent tetrahydrofuran leads to porous and inhomogeneous films, spin coating with anisole as solvent provides homogeneous films of cyanoacrylate with a thickness of only 4 nm. This allows surface-sensitive analytical methods to access the interface and possible interactions can be characterized in-situ. [ABSTRACT FROM AUTHOR]

Structural Health Monitoring (SHM) systems are commonly integrated in bonded joints for different applications in order to detect and predict potential fatigue and damages caused by internal and external agents they are subjected to during their operation life. However, each of the current SHM systems presents some drawbacks, as the reduction of structural properties or the difficulty in its implementation. This work deals with the use of a Carbon Nanotube film (Bukypaper) as a sensor in double cantilever beam (DCB) bonded joint specimens for crack growth monitoring purposes. Buckypaper (BP) sheets were manufactured and integrated in adhesive film layers and its integration quality was studied by Scanning Electron Microscopy (SEM). The effect of the integration of different thickness BPs in the mechanical performance of the bonded joints was also assessed performing DCB fracture tests. Also, electro-mechanical tests were conducted using the BP as the sensor, monitoring the output in the electrical resistance during the crack propagation. It was observed the capability of BP to detect and locate the damage during the test with a linear dependence between the electrical resistance measured in the BP and the deduced crack growth, proving the potential of the BP to monitor self-sensing bonded joints. [ABSTRACT FROM AUTHOR]

The purpose of this in vitro prospective nonrandomized study is to compare the toxicity and strength of cyanoacrylate and hydrogel adhesives on human retinal pigment epithelium (RPE) cells and porcine retina, respectively. The toxicity of cyanoacrylate (histoacryl, dermabond, superglue), ReSure PEG, and Tisseel fibrin glue on human RPE cells was determined by growing RPE cells in vitro, applying the different adhesives to the cells, and monitoring for disruption of growth over 3 days. The relative strength of these adhesives was tested by gluing a 3 mm piece of foam to a porcine retina and determining the amount of force needed to break the attachment. 0.085 N of force was required to break the porcine retinal tissue (p =.913). Histoacryl adhesive exhibited high strength (0.247 N) and high RPE toxicity (0.55 mm inhibition zone after 24 hrs). The strength of Tisseel fibrin glue was 0.078 N while that of ReSure was only 0.053 N. Both Tisseel and ReSure were nontoxic to the RPE cells. Tisseel VH fibrin sealant may provide the best option for sealing retinal breaks because of its high strength and low retinal toxicity. [ABSTRACT FROM AUTHOR]

Bi-directional corrugated honeycomb aluminum has two-way energy absorption performance intended to be used as impact limiter filling material for nuclear spent fuel transport casks. It is made of aluminum plate, corrugated plate and adhesive. The bonding parameters determine the bonding effect of Bi-directional corrugated honeycomb aluminum thus affect the energy absorption performance. This paper verifies the bonding parameters from three aspects (type of adhesive, surface roughness, and thickness of the adhesive layer). The results show that when an acrylic adhesive is used to perform the compression test, no matter which bonding parameters are used, all samples debond. When an epoxy resin is used, except for the sample with an adhesive layer thickness of 0.2 mm and the surface was polished with the grit number of 320 sandpaper, samples with other parameters showed debonding to varying degrees. In addition, the bonding parameters have a great influence on the energy absorption performance of the specimen. The deformation and the energy absorption was also discussed. [ABSTRACT FROM AUTHOR]

The lap shear strength of epoxy adhesive is determined experimentally using adhesive-bonded single lap joints with two similar adherends, aluminium alloy and steel, following ASTM standards D1002 and D905 in tensile and compressive loading. Thicknesses of the adhesive layer are 25 μm, 50 μm, 75 μm, 100 μm and 125 μm. Both tensile and compressive shear strength increase with increase in thickness of adhesive layer up to 100 μm, and it decreases at 125 μm of thickness of adhesive layer. Analysis of fractured surfaces of joints reveals that cohesive mode of failure dominated for the joint with 100 μm of thickness of adhesive layer. Compressive shear strength of the joints is higher than the tensile shear strength of joints at all the thicknesses. Further, the shear strength of joints with aluminium alloy adherends is higher than that of joints with steel adherends for both types of loading. The higher strength of aluminium alloy joints could be attributed to the surface roughness and materials of the adherends. The effect of surface roughness on shear strength is more pronounced compared to the material of adherends, i.e. aluminium alloy and steel. [ABSTRACT FROM AUTHOR]

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Solvent-based polychloroprene (CR) adhesive was formulated using four different types of tackifiers. Wood rosin (WD), coumarone-indene resin (CI), terpene-phenolic resin (TP) and para-tert-butyl phenol-formaldehyde (TBPF) resin were incorporated with CR at various amounts say 20–50 phr (parts per hundred rubber). The effect of nature and amount of resins on adhesion strength was measured on both leather to leather and rubber to rubber joints. Results indicated that the nature of resins greatly influenced the performance of the CR adhesive. The peel strength of CR/TBPF adhesive was higher than that of CR/TP, CR/CI and CR/WD adhesives. It was found that incorporation of TBPF resin also improved the thermal ageing resistance of the bonded joints. The properties of CR/resin adhesive were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The interaction between the resin and CR was studied using FTIR spectroscopy. All the four tackifiers used were compatible with CR as confirmed by the DSC analysis. [ABSTRACT FROM AUTHOR]

This study found that the substitution of 6% unbleached cellulose nanofibers (LCNF) into pMDI allowed for a reduction in density of 0.09 and 0.08 g/cm3 for equivalent performance in modulus of elasticity and modulus of rupture respectively; while, all other properties except internal bond were maintained. For panels made above 0.60 g/cm3, it was found that blows would consistently occur due to additional steam pressure from LCNF addition. However, below 0.60 g/cm3 and at 210°C press temperature, all blows at the laboratory scale were eliminated. Industrially, these findings suggests that a company could possibly make a lower density oriented strand board (OSB) of equivalent or better dry mechanical properties while reducing panel weight and avoiding blows. Moving forward, future studies will need to tackle viscosity issues at the sprayer. Our qualitative observation during spraying found that it may be possible to spray up to 3% LCNF without clogging, but at 6% clogging was a mild problem. More research should be performed to improve the homogeneity of spraying at higher substitution rates to assist with industrial commercialization. [ABSTRACT FROM AUTHOR]

Peanut meal (PM) as the raw material was crosslinked modification by different mass fractions of 4,4′-diphenylmethane diisocyanate (MDI), to prepare adhesives for label. The properties of the adhesives, including water resistance, the viscosity and solid content were investigated. The performance of the label adhesive modified using MDI were significantly higher than those of the unmodified adhesive, making it suitable for applications in the labels. The water resistance duration was up form 3 h to 77 h when the modifier was added at 15 wt.% (based on PM). Further, the viscosity of the modified adhesive increased to an appropriate 82.2 Pa·s, and its solid content increased from 16.01% to 18.16%. In addition, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) were used to characterize the chemical interactions in the cured adhesives, and the thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to analyze the reason of adhesive performance improvement. It was found that incorporating MDI into the adhesives resulted in the formation of a dense crosslinking network structure because of chemical reactions between MDI and active groups on the protein molecules and the introduction of hydrophobic groups in the adhesives; these factors effectively prevented water penetration, thus improving the water resistance of the cured adhesives. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of pre-heating a dual-polymerized adhesive and a dual-polymerized core build-up resin composite on their dentin micro-shear bond strength (µSBS), degree of conversion (DC%) and ultimate tensile strength (UTS). For µSBS, 45 human molars were divided into 9 groups (n = 5) according to two factors: (1) Adhesive temperature (25 °C/32 °C/40 °C) and 2- Resin composite temperature (25 °C/32 °C/40 °C). Dual-polymerized adhesive (Futurabond U/FBU) was applied over occlusal dentin at each temperature following the manufacturer's instructions. Four dual-polymerized composites (Rebilda DC/RDC, VOCO) micro-cylinders (1.2 mm diameter × 1 mm height) were built-up over each dentin disc, after being pre-heated at each temperature. After storage (48 h/37 °C), µSBS testing was run at a crosshead speed of 1 mm/min. DC% of FBU/RDC was evaluated at each temperature after 48 h using FTIR. Hourglass-shaped specimens were fabricated from both materials at each respective temperature and pulled apart to evaluate UTS after 48 h storage. Data were analyzed by ANOVA/Tukey's test/Pearson's correlation (p = 0.05). Neither adhesive/composite temperature nor their interaction had a significant effect on µSBS. No significant difference in µSBS between groups, except within 40 °C FBU. Predominant failure mode was a mixed type. No significant difference in DC% of FBU groups. RDC at 40 °C had significantly higher DC% than 25 °C. No significant difference in UTS of FBU and RDC groups. Application of both dual-polymerized adhesive and resin composite at 40 °C seemed to reduce µSBS. Raising the temperature to 40 °C improved DC% of resin composite, with no effect on adhesive. Pre-heating did not influence the UTS of both materials. [ABSTRACT FROM AUTHOR]

In this research, graft copolymerization of Methyl methacrylate (MMA; hereafter) on to Polychloroprene rubber (CR; hereafter) has been processed in the presence of hydrogen peroxide as an initiator. Grafting reaction has been carried out in a mechanical mixer, and factors such as time, temperature, monomer, and initiator's concentration were investigated and optimized. FTIR confirmed the grafting reaction occurred in the CR polymer as evident from a peak of a carbonyl group. The adhesive strength of grafted adhesive was analyzed by standard peel testing on canvas--canvas and leather--leather substrates. The effect of variation in environmental conditions such as storage time, exposure to elevated temperature, and immersion of adhesively joined substrates in the water on the peel strength of adhesive bonding was also studied. The results were compared with the strength of commercially available adhesives in local market. The solid content of grafted adhesive (55%) showed their greater applicability and high strength characteristics. The maximum peel strength achieved was 79N/mm for canvas--canvas while 73 N/mm for leather--leather substrates. The percentage fall in peel strength after exposure to different environmental conditions was shallow as compared to commercially available adhesives. 'GA-13' the grafted adhesive has a high potential for the Leather-base industry and other applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare, under varying conditions, the dentin shear bond strength (SBS) of three solvent-containing (acetone, ethanol, and water) self-etch adhesive with acetone-containing self-etch adhesive and ethanol/water-containing self-etch adhesive. One-hundred non-carious molar teeth were divided into 10 groups of ten specimens each. Kerr Optibond All-In-One (containing acetone, ethanol, and water), Ivoclar Tetric N-Bond Universal (containing ethanol and water), and Shofu BeautiBond (containing acetone) were used as adhesives. The comparisons were made only between adhesives containing common solvents. Three bulk-fill resin composites, Kerr Sonicfill 2, Ivoclar Tetric N-Ceram Bulk Fill, and Shofu Beautifil-Bulk, were chosen for preparation of two-millimeter blocks of composites. Specimens were tested in a universal testing machine (Shimadzu, Japan) in shear to failure at 0.5 mm/min. The shear bond strengths were tested under two conditions: immediately and after 10,000 thermal cycling. The mean values were compared using analysis of variance (ANOVA]. A significance level of p < 0.05 was used in all tests. Failures were categorized into four classes: adhesive failure, cohesive failure in dentin, cohesive failure in the composite, and mix-type failure. Tetric N-Ceram Bulk Fill + Tetric N-Bond Universal showed the highest SBS values both two conditions. The megapascal pressure unit (MPa) was 19.38 (± 3.06) in immediate group, while the MPa after thermocycle aging was 10.68 (± 2.5]. The SBS of three solvent-containing adhesives was not affected by the content of bulk-fill composites. After thermal aging, there was a significant decrease in the SBS of all groups. [ABSTRACT FROM AUTHOR]

Byssuses, which are proteinaceous fibers secreted by mollusks, are remarkable underwater adhesives. Although mussel adhesives are well known, much less is known about the byssal proteins of pearl oysters especially in the adhesive regions. In this study, adhesive proteins from the pearl oyster Pinctada fucata were studied in depth by transcriptomics and proteomics approaches. In total, 16 novel proteins were identified including a von Willebrand factor type A domain-containing protein, a thrombospondin-1-like protein, tyrosinase, mucin-like proteins, protease inhibitors, and Pinctada unannotated foot protein 3 (PUF3) to PUF6. Interestingly, PUF3-6 are enriched with glycine, serine, and PXG (X = F/Y/W/K/L) motifs and are highly expressed in the foot. The identification of byssal proteins of the pearl oyster is a key step for understanding byssus formation and may inspire the synthesis of novel adhesives for underwater use and the development of anti-biofouling strategies. [ABSTRACT FROM AUTHOR]

The effect of nanosilicates on the performance of natural rubber latex (NRL)-based adhesives was studied. For comparison, a reference filler (Kaolin clay) was included in the study. Natural leather was used as the adherend and the adhesive strength was recorded by measuring the peel strength. The results indicated that incorporation of nanosilicates imparted increased peel strength to NRL-based adhesives. Transmission electron microscopy (TEM) studies confirm the excellent dispersion of silicate platelets in the NR matrix. Peel strength showed maximum value for NRL-based adhesive containing 2phr nanosilicate. The results of thermogravimetric analysis (TGA) showed that addition of nanosilicates imparted better thermal stability into the adhesives. Conventional clay could not make any improvement in properties of the adhesives. Viscosity of NRL-based adhesive was increased by the addition of the nanosilicates which confirms the better dispersion of the nanofiller into the NR matrix. Fourier transform infrared (FTIR) spectroscopic analysis and contact angle measurements of the NRL/nanosilicate adhesives were also carried out. [ABSTRACT FROM AUTHOR]

Okoume wood is widely known for having an excellent unwinding capability. This hardwood species was used for tannin extraction in order to formulate for the first time tropical hardwood, an eco-friendly adhesive. The tannins were extracted from the bark, then mixed to hexamine for hardening. The system obtained showed high values of the elasticity modulus (3681 MPa; 3752 M Pa; 3894 MPa; 3971 MPa) according to the thermomechanical analysis. A good cohesive index of ≥80% and ≥60% based on standard NF EN 314-1 and NF EN 314-2. 1H NMR analysis was used to understand the reactivity between Okoume tannins and hexamine and also to compare the reactivity with hexamine of tannins extracted from different Okoume barks. Thermal stability control revealed advanced thermal degradation of the adhesive system. [ABSTRACT FROM AUTHOR]

Wheat starch paste (WSP) is an adhesive commonly used in the field of book and paper conservation. Each conservation studio must regularly prepare WSP in small batches because of its very short shelf life. Over time this has led to the development of a corpus of ad-hoc recipes and sometimes contradictory practices. This article attempts to rationally analyse WSP preparation and to identify what parameters may affect the quality of the end-product for conservation use. After collecting over 50 recipes from publications and conservation professionals, a set of eight parameters were identified: starch source, pre-soaking, starch-to-water ratio, cooking method, cooking duration, cooking temperature, sieving and storage time/method. A set of 72 cooking experiments were then conducted varying each of these parameters in turn. The findings presented here are intended to provide a set of practical guidelines to help conservators optimise their paste-making processes and identify which practices and parameters had no measurable effect on paste quality and, conversely, which ones did; and for the latter, to provide a well-defined range of values for the production of a very homogeneous quality product, suitable for conservation work. It is important to stress that this research has only scratched the surface of conservation WSP quality analysis, leaving many areas open to further study. [ABSTRACT FROM AUTHOR]

In this study, the shear strength of a nanocomposite adhesive was experimentally and numerically investigated under ambient temperature and thermal cycling conditions. This study used the Thick Adherend Shear Test method, which is commonly used to determine the shear stress–displacement of adhesives. Shear–displacement was determined by an extensometer to accurately compare results obtained from the Thick Adherend Shear Test results for joints with numerical analyses. As a result, when the shear failure load obtained from experiments was examined, the nanocomposite adhesives, obtained by adding a nanostructure into the adhesive, improved both the ambient temperature and thermal cycling performances of the joints. [ABSTRACT FROM AUTHOR]