The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
John G Dillard - One of the best experts on this subject based on the ideXlab platform.
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crack path selection in adhesively bonded joints the roles of external loads and speciment geometry
International Journal of Fracture, 2002Co-Authors: Buo Chen, David A Dillard, John G Dillard, Richard L ClarkjrAbstract:This paper investigates the roles of external loads and specimen geometry on crack path selection in adhesively bonded joints. First, the effect of mixed mode fracture on crack path selection is studied. Using epoxy as an adhesive and aluminum as the adherends, double cantilever beam (DCB) specimens with various T-stress levels are prepared and tested under mixed mode fracture loading. Post-Failure analyses on the Failure surfaces using X-ray photoelectron spectroscopy (XPS) suggest that the Failure tends to be more interfacial as the mode II fracture component in the loading increases. This fracture mode dependence of the Locus of Failure demonstrates that the Locus of Failure is closely related to the direction of crack propagation in adhesive bonds. Through analyzing the crack trajectories in failed specimens, the effect of mixed mode fracture on the directional stability of cracks is also investigated. The results indicate that the direction of the crack propagation is mostly stabilized when more than 3% of mode II fracture component is present at the crack tip regardless of the T-stress levels in the specimens for the material system studied. Second, using a high-speed camera to monitor the fracture sequence in both quasi-static and low-speed impact tests, the effect of debond rate on the Locus of Failure and directional stability of cracks is investigated. Post-Failure analyses including XPS, Auger electron spectroscopic depth profile, and scanning electron microscopy indicate that as the crack propagation rate increases, the Failure tends to be more cohesive and the cracks tend to be directionally unstable. Last, as indicated by the finite element analyses results, the T-stresses, and therefore the directional stability of cracks in adhesive bonds, are closely related to the thickness of the adhesive layer and also the thickness of adherend. This specimen geometry dependence of crack path selection is studied analytically and is verified experimentally.
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Crack Path Selection in Adhesively-Bonded Joints: The Role of Material Properties
The Journal of Adhesion, 2001Co-Authors: Buo Chen, David A Dillard, John G Dillard, Richard L ClarkAbstract:Abstract This paper investigates the role of material properties on crack path selection in adhesively bonded joints. First, a parametric study of directionally unstable crack propagation in adhesively-bonded double cantilever beam specimens (DCB) is presented. The results indicate that the characteristic length of directionally unstable cracks varies with the Dundurs' parameters characterizing the material mismatch. Second, the effect of interface properties on crack path selection is investigated. DCB specimens with substrates treated using various surface preparation methods are tested under mixed mode fracture loading to determine the effect of interface properties on the Locus of Failure. As indicated by the post-Failure analyses, debonding tends to be more interfacial as the mode II fracture component in the loading increases. On the other hand, Failures in specimens prepared with more advanced surface preparation techniques appear more cohesive for given loading conditions. Using a high-speed camer...
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Chlorination of SBS rubbers with different styrene contents using trichloro-isocyanuric acid
Journal of Adhesion Science and Technology, 1999Co-Authors: José Iniesta-jaén, M. Mercedes Pastor-blas, José Miguel Martín-martínez, M. Mar Mahiques-bujanda, John G DillardAbstract:In order to improve their adhesion to polyurethane adhesives, three unvulcanized block styrene-butadiene-styrene (SBS) rubbers with styrene contents between 33% and 55% were surface-treated with solutions of 2 wt% trichloro-isocyanuric acid (TCI) in ethyl acetate. The joint strength was estimated using T-peel tests and the failed surfaces were analyzed to assess the Locus of Failure. The failed surfaces were analyzed using ATR-IR spectroscopy, contact angle measurements, XPS, and SEM. An unexpected trend in the joint strength was obtained because the Locus of Failure depended on both the styrene content and the mechanical properties of each SBS rubber. A mixed mode of Failure was obtained in joints produced with S 1 rubber (33 wt% styrene content), whereas Failure in the chlorinated layer was observed with S3 rubber (55 wt% styrene content); cohesive Failure in the adhesive was found for the joints produced with S2 rubber (44 wt% styrene content).
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effect of the t stress in the adhesively bonded joints on the Locus of Failure in rubber toughened epoxy system
Proceedings of 3rd International Conference on Adhesive Joining and Coating Technology in Electronics Manufacturing 1998 (Cat. No.98EX180), 1998Co-Authors: B Chen, David A Dillard, John G DillardAbstract:Summary form only given. This study addresses T-stress effects on the Locus of Failure in adhesively bonded joints. Double cantilever beam (DCB) specimens were made using Al 6061-T6 adherends and DER 331 epoxy resin with rubber concentrations from 0% to 8%. In order to obtain different stress levels, specimens were loaded uniaxially to plastically deform the adherends. T-stress increased with the plastic deformation left in the specimen upon unloading. Under mode I loading, unstable or alternating crack propagation was seen when the T-stress in the specimen increased. After this stability transition occurred, Failure occurred at or very close to the interfaces. However, the T-stress level where the stability transition occurred increased with adhesive rubber concentration. Post-Failure XPS and SEM analysis showed that as rubber concentrations in the adhesive increased, Failure tended to be more cohesive. FEA modeling using Franc2DI was conducted to predict crack propagation behavior. Results showed that when the crack is perturbed by an air bubble or flaw ahead of the crack tip, the crack continued to deviate from its original path if the T-stress was tensile. However, if the T-stress was compressive, a deviated crack would converge back to its original path. The convergence rate depended on the T-stress value. The FEA also predicted that under mode I loading, T-stress in specimens with thinner adherends was higher than that in specimens with thicker adherends, and Failure tended to occur closer to the interfaces. This prediction was verified using DER 331 epoxy resin with 8.1% rubber and Al 6061-T6 adherends of varying thickness.
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Failure analysis of surface treated unvulcanized sbs rubber polyurethane adhesive joints
International Journal of Adhesion and Adhesives, 1997Co-Authors: Mercedes M Pastorblas, J M Martinmartinez, Rosa Torregrosamacia, John G DillardAbstract:Abstract The surface of an unvulcanized styrene-butadiene-styrene (SBS) rubber (S0) was chlorinated with 0.5–7wt% trichloroisocyanuric acid (TCI) solutions. The adhesion strength of surface-treated SO rubber/polyurethane adhesive joints was obtained from T-peel tests. The failed surfaces after peeling were characterized by ATR-IR spectroscopy, contact angle measurements, SEM coupled with EDX analysis and XPS. The untreated SO rubber shows no adhesion because of a lack of compatibility with the polyurethane adhesive. Chlorination of SO rubber with O.5wt% TCl produced a noticeable increase in T-peel strength which was due to the formation of CCl and CO species on the rubber surface, the Failure of the joint being produced at the chlorinated surface (weak boundary layer). Treatment of S0 rubber with greater concentrations of TCI, up to 2wt%, resulted in a decrease in the joint strength because the Locus of Failure was directed deeper into the chlorinated layer. On the other hand, the treatment of S0 rubber with 7wt% TCI produced different joint strength values in replicate joints that were tested under similar experimental conditions, mainly owing to differences in the Locus of Failure in the joints. Failure occurred randomly throughout the adhesive, the interface or the surface chlorinated layer.
José Miguel Martín-martínez - One of the best experts on this subject based on the ideXlab platform.
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Adhesion of surface-treated EVA to polychloroprene adhesive containing different polyisocyanate content
International Journal of Adhesion and Adhesives, 2005Co-Authors: Asunción Martínez-garcía, Ana Sánchez-reche, José Miguel Martín-martínezAbstract:Abstract Different amounts of a polyisocyanate (3–5 wt%) were added to a polychloroprene (PCP) adhesive to determine their influence on the adhesion properties of an ethylene vinyl acetate copolymer containing 12 wt% vinyl acetate (EVA12). EVA12 was treated with sulphuric acid to increase its adhesion, and improved wettability, creation of carbon–oxygen moieties and roughness were achieved. The thermal, rheological and surface properties of the PCP and polyisocyanate mixtures were obtained. The higher the polyisocyanate content in the PCP, the higher the peel strength value of sulphuric acid-treated EVA12 adhesive joints. By increasing the polyisocyanate content in the adhesive, the Locus of Failure changed from adhesion to mixed (adhesion+cohesion in EVA12). The ageing of the sulphuric acid-treated EVA12/PCP+polyisocyanate adhesive joints produced a decrease in T-peel strength, although always a cohesive Failure in the EVA12 was obtained.
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Mechanisms of Adhesion in Surface Chlorinated Thermoplastic Rubber/Thermoplastic Polyurethane Adhesive Joints
Rubber Chemistry and Technology, 2002Co-Authors: M. Mercedes Pastor-blas, José Miguel Martín-martínez, F. J. BoerioAbstract:Abstract Chlorination of a thermoplastic styrene-butadiene-styrene rubber (S0) with a solution of 2 wt% trichloroisocyanuric acid (TCI) in ethyl acetate improved its adhesion to polyurethane adhesives. The analysis of the failed surfaces (obtained after T-peel test of S0/PU joints) showed that the Locus of Failure in the rubber/polyurethane joints progresses from adhesion (in non chlorinated-S0/PU joint) to cohesion in the chlorinated layer (for chlorinated-S0/PU joint). The composition of this chlorinated layer differed from the composition of the non bonded-chlorinated rubber, i.e. the Failure of the joint was located in a chlorinated layer with a distinctive chemistry. On the other hand, the analysis of the chlorinated rubber/PU adhesive interface showed that chlorination with TCI produces a crosslinking of the rubber surface as well as strong interactions between the uppermost-chlorinated layer and the PU adhesive.
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Assessment of the Locus of Failure of oxygen plasma-treated rubber/polyurethane adhesive joints using XPS and IRATR spectroscopy
Surface and Interface Analysis, 2000Co-Authors: M. Mercedes Pastor-blas, Teresa Del Pilar Ferrándiz-gómez, José Miguel Martín-martínezAbstract:The peel strength of oxygen plasma-treated rubber/polyurethane adhesive joints was measured as a function of the length of the treatment. The trend obtained did not obey the expected mechanisms of adhesion and therefore the precise determination of the Locus of Failure of the joints was carried out using XPS and infrared attenuated total reflectance (IRATR) spectroscopy. The oxygen plasma treatment for 1 min facilitated the migration of wax to the surface, which was transferred to the adhesive surface during the curing process. The increase in the length of the treatment up to 20 min produced a change in the Locus of Failure, which is mixed (adhesional in the oxidized rubber layer and cohesional in the wax layer). The oxygen plasma for 40 min produces a damaged oxidized rubber layer, which acts as a weak layer producing a decrease in peel strength and a cohesive Failure in that oxidized layer. Copyright © 2000 John Wiley & Sons, Ltd.
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Chlorination of SBS rubbers with different styrene contents using trichloro-isocyanuric acid
Journal of Adhesion Science and Technology, 1999Co-Authors: José Iniesta-jaén, M. Mercedes Pastor-blas, José Miguel Martín-martínez, M. Mar Mahiques-bujanda, John G DillardAbstract:In order to improve their adhesion to polyurethane adhesives, three unvulcanized block styrene-butadiene-styrene (SBS) rubbers with styrene contents between 33% and 55% were surface-treated with solutions of 2 wt% trichloro-isocyanuric acid (TCI) in ethyl acetate. The joint strength was estimated using T-peel tests and the failed surfaces were analyzed to assess the Locus of Failure. The failed surfaces were analyzed using ATR-IR spectroscopy, contact angle measurements, XPS, and SEM. An unexpected trend in the joint strength was obtained because the Locus of Failure depended on both the styrene content and the mechanical properties of each SBS rubber. A mixed mode of Failure was obtained in joints produced with S 1 rubber (33 wt% styrene content), whereas Failure in the chlorinated layer was observed with S3 rubber (55 wt% styrene content); cohesive Failure in the adhesive was found for the joints produced with S2 rubber (44 wt% styrene content).
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Failure analysis of surface-treated unvulcanized SBS rubber/polyurethane adhesive joints
International Journal of Adhesion and Adhesives, 1997Co-Authors: M. Mercedes Pastor-blas, José Miguel Martín-martínez, Rosa Torregrosa-maciá, John G DillardAbstract:Abstract The surface of an unvulcanized styrene-butadiene-styrene (SBS) rubber (S0) was chlorinated with 0.5–7wt% trichloroisocyanuric acid (TCI) solutions. The adhesion strength of surface-treated SO rubber/polyurethane adhesive joints was obtained from T-peel tests. The failed surfaces after peeling were characterized by ATR-IR spectroscopy, contact angle measurements, SEM coupled with EDX analysis and XPS. The untreated SO rubber shows no adhesion because of a lack of compatibility with the polyurethane adhesive. Chlorination of SO rubber with O.5wt% TCl produced a noticeable increase in T-peel strength which was due to the formation of CCl and CO species on the rubber surface, the Failure of the joint being produced at the chlorinated surface (weak boundary layer). Treatment of S0 rubber with greater concentrations of TCI, up to 2wt%, resulted in a decrease in the joint strength because the Locus of Failure was directed deeper into the chlorinated layer. On the other hand, the treatment of S0 rubber with 7wt% TCI produced different joint strength values in replicate joints that were tested under similar experimental conditions, mainly owing to differences in the Locus of Failure in the joints. Failure occurred randomly throughout the adhesive, the interface or the surface chlorinated layer.
M. Mercedes Pastor-blas - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms of Adhesion in Surface Chlorinated Thermoplastic Rubber/Thermoplastic Polyurethane Adhesive Joints
Rubber Chemistry and Technology, 2002Co-Authors: M. Mercedes Pastor-blas, José Miguel Martín-martínez, F. J. BoerioAbstract:Abstract Chlorination of a thermoplastic styrene-butadiene-styrene rubber (S0) with a solution of 2 wt% trichloroisocyanuric acid (TCI) in ethyl acetate improved its adhesion to polyurethane adhesives. The analysis of the failed surfaces (obtained after T-peel test of S0/PU joints) showed that the Locus of Failure in the rubber/polyurethane joints progresses from adhesion (in non chlorinated-S0/PU joint) to cohesion in the chlorinated layer (for chlorinated-S0/PU joint). The composition of this chlorinated layer differed from the composition of the non bonded-chlorinated rubber, i.e. the Failure of the joint was located in a chlorinated layer with a distinctive chemistry. On the other hand, the analysis of the chlorinated rubber/PU adhesive interface showed that chlorination with TCI produces a crosslinking of the rubber surface as well as strong interactions between the uppermost-chlorinated layer and the PU adhesive.
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Assessment of the Locus of Failure of oxygen plasma-treated rubber/polyurethane adhesive joints using XPS and IRATR spectroscopy
Surface and Interface Analysis, 2000Co-Authors: M. Mercedes Pastor-blas, Teresa Del Pilar Ferrándiz-gómez, José Miguel Martín-martínezAbstract:The peel strength of oxygen plasma-treated rubber/polyurethane adhesive joints was measured as a function of the length of the treatment. The trend obtained did not obey the expected mechanisms of adhesion and therefore the precise determination of the Locus of Failure of the joints was carried out using XPS and infrared attenuated total reflectance (IRATR) spectroscopy. The oxygen plasma treatment for 1 min facilitated the migration of wax to the surface, which was transferred to the adhesive surface during the curing process. The increase in the length of the treatment up to 20 min produced a change in the Locus of Failure, which is mixed (adhesional in the oxidized rubber layer and cohesional in the wax layer). The oxygen plasma for 40 min produces a damaged oxidized rubber layer, which acts as a weak layer producing a decrease in peel strength and a cohesive Failure in that oxidized layer. Copyright © 2000 John Wiley & Sons, Ltd.
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Chlorination of SBS rubbers with different styrene contents using trichloro-isocyanuric acid
Journal of Adhesion Science and Technology, 1999Co-Authors: José Iniesta-jaén, M. Mercedes Pastor-blas, José Miguel Martín-martínez, M. Mar Mahiques-bujanda, John G DillardAbstract:In order to improve their adhesion to polyurethane adhesives, three unvulcanized block styrene-butadiene-styrene (SBS) rubbers with styrene contents between 33% and 55% were surface-treated with solutions of 2 wt% trichloro-isocyanuric acid (TCI) in ethyl acetate. The joint strength was estimated using T-peel tests and the failed surfaces were analyzed to assess the Locus of Failure. The failed surfaces were analyzed using ATR-IR spectroscopy, contact angle measurements, XPS, and SEM. An unexpected trend in the joint strength was obtained because the Locus of Failure depended on both the styrene content and the mechanical properties of each SBS rubber. A mixed mode of Failure was obtained in joints produced with S 1 rubber (33 wt% styrene content), whereas Failure in the chlorinated layer was observed with S3 rubber (55 wt% styrene content); cohesive Failure in the adhesive was found for the joints produced with S2 rubber (44 wt% styrene content).
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Failure analysis of surface-treated unvulcanized SBS rubber/polyurethane adhesive joints
International Journal of Adhesion and Adhesives, 1997Co-Authors: M. Mercedes Pastor-blas, José Miguel Martín-martínez, Rosa Torregrosa-maciá, John G DillardAbstract:Abstract The surface of an unvulcanized styrene-butadiene-styrene (SBS) rubber (S0) was chlorinated with 0.5–7wt% trichloroisocyanuric acid (TCI) solutions. The adhesion strength of surface-treated SO rubber/polyurethane adhesive joints was obtained from T-peel tests. The failed surfaces after peeling were characterized by ATR-IR spectroscopy, contact angle measurements, SEM coupled with EDX analysis and XPS. The untreated SO rubber shows no adhesion because of a lack of compatibility with the polyurethane adhesive. Chlorination of SO rubber with O.5wt% TCl produced a noticeable increase in T-peel strength which was due to the formation of CCl and CO species on the rubber surface, the Failure of the joint being produced at the chlorinated surface (weak boundary layer). Treatment of S0 rubber with greater concentrations of TCI, up to 2wt%, resulted in a decrease in the joint strength because the Locus of Failure was directed deeper into the chlorinated layer. On the other hand, the treatment of S0 rubber with 7wt% TCI produced different joint strength values in replicate joints that were tested under similar experimental conditions, mainly owing to differences in the Locus of Failure in the joints. Failure occurred randomly throughout the adhesive, the interface or the surface chlorinated layer.
John F Watts - One of the best experts on this subject based on the ideXlab platform.
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understanding the relationship between silane application conditions bond durability and Locus of Failure
International Journal of Adhesion and Adhesives, 2006Co-Authors: Marielaure Abel, R P Digby, R D Allington, N Porritt, S J Shaw, John F WattsAbstract:Abstract The extent to which an organosilane surface treatment regime can promote durability enhancement of an adhesively bonded aluminium alloy system has been determined. Results have revealed the range of application and film-conditioning parameters which contribute to joint durability in a simple Boeing wedge joint. Organosilane solution parameters relating to solvent type, solution concentration, pH and hydrolysis time have all been shown to influence resultant durability. Interestingly, parameters such as film drying temperature and in-process time delay (time interval between application of the organosilane to the alloy surface and subsequent bonding) have little influence on joint performance. The factors responsible for the durability variations observed have been considered using various surface analytical techniques. Superficially, Failure surfaces indicative of interfacial Failure between substrate and adhesive have been observed. More detailed characterisation using both XPS and SIMS has indicated Failure processes associated with a ‘diffusion zone’ comprising aluminium oxide and the organosilane.
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Understanding the relationship between silane application conditions, bond durability and Locus of Failure
International Journal of Adhesion and Adhesives, 2006Co-Authors: M.-l. Abel, R P Digby, R D Allington, N Porritt, S J Shaw, John F WattsAbstract:The extent to which an organosilane surface treatment regime can promote durability enhancement of an adhesively bonded aluminium alloy system has been determined. Results have revealed the range of application and film-conditioning parameters which contribute to joint durability in a simple Boeing wedge joint. Organosilane solution parameters relating to solvent type, solution concentration, pH and hydrolysis time have all been shown to influence resultant durability. Interestingly, parameters such as film drying temperature and in-process time delay (time interval between application of the organosilane to the alloy surface and subsequent bonding) have little influence on joint performance. The factors responsible for the durability variations observed have been considered using various surface analytical techniques. Superficially, Failure surfaces indicative of interfacial Failure between substrate and adhesive have been observed. More detailed characterisation using both XPS and SIMS has indicated Failure processes associated with a 'diffusion zone' comprising aluminium oxide and the organosilane. Crown Copyright © 2005 Published by Elsevier Ltd. All rights reserved
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influence of formulation chemistry on the Locus of Failure of adhesive joints
Surface and Interface Analysis, 1995Co-Authors: A M Taylor, C H Mclean, M Charlton, John F WattsAbstract:The durability of photocured resins adhered to ceramic substrates has been investigated. Monochromated XPS and time-of-flight SIMS were employed to determine the precise Locus of Failure in butt-joints comprised of a photocured resin adhered to either a 96% pure, debased alumina substrate or single-crystal silicon. Prolonged (> 14 days) immersion in water at 50°C resulted in cohesive Failure, with 1–2 nm of polymer remaining on one of the ceramic substrates. An absence in the spectrum of any components attributable to characteristic groups from a major constituent of the polymer within this overlayer suggested the possibility that one of the minor resin components was aggregating at the organic/inorganic interface to produce an in situ weak boundary layer. The interactions of some of the organic molecules present in the formulation with the α-alumina substrate were investigated using molecular modelling techniques to indicate the most favourable interactions with the substrate. Durability studies were also carried out on a reformulated photocured resin to investigate the effect of removal of the ethoxylated methacrylate monomer, suspected of being the principal organic component at the weak boundary layer, on both joint performance and Locus of Failure.
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the definition of the Locus of Failure on ceramic substrates the benefit of monochromated xps
Journal of Adhesion, 1994Co-Authors: John F Watts, Alison M TaylorAbstract:The use of X-ray photoelectron spectroscopy (XPS) to assess the Locus of Failure of a photo-cured resin on an alumina substrate is reported. It is shown that the carbon 1s spectra obtained with conventional (achromatic) and monochromatic photon sources are markedly different. The spectrum obtained with the monochromatic source reveals the fine structure associated with the polymer whilst the spectrum recorded with the conventional source is distorted by differential charging. This observation has important ramifications when XPS is used for the definition of the Locus of Failure of organic coatings, or adhesives, applied to insulating substrates such as ceramics.
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A comparative study of the influence of surface pretreatment on the Failure characteristics of adhesively bonded titanium
Surface and Interface Analysis, 1992Co-Authors: John F Watts, B. R. DempsterAbstract:The durability of adhesive joints fabricated from two titanium alloys, commercially pure titanium (TA6) and Ti–6Al–4V (TA10), has been investigated using the wedge cleavage test. Seven different methods of adherend pretreatment were investigated: writ blasting (GB), chromatic acid anodizing (CAA) and sodium hydroxide anodizing (SHA), used alone and with the addiiton of an epoxy primer prior to adhesive bonding. A silane adhesion promoter was also used in conjunction with the grit-blasted adherend. As expected, the durability depended critically on the substrate pretreatment, with SHA-treated joints giving the best durability and GB the worst performance. The application of a primer or adhesion promoter tended to improve the situation somewhat. The Failure mode was apparently adhesive (interfacial), but when the interfacial Failure surfaces were examined by XPS, polymeric residues were identified on the adherend surfaces of all joints. In the case of those joints that exhibited good durability three was evidence of transfer of titanium to the polymer side of the Locus of Failure. The Locus of Failure in these cases may be described in terms of a mixed mode Failure on a microscale.
Mercedes M Pastorblas - One of the best experts on this subject based on the ideXlab platform.
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assessment of the Locus of Failure of oxygen plasma treated rubber polyurethane adhesive joints using xps and iratr spectroscopy
Surface and Interface Analysis, 2000Co-Authors: Mercedes M Pastorblas, Teresa Del Pilar Ferrandizgomez, J M MartinmartinezAbstract:The peel strength of oxygen plasma-treated rubber/polyurethane adhesive joints was measured as a function of the length of the treatment. The trend obtained did not obey the expected mechanisms of adhesion and therefore the precise determination of the Locus of Failure of the joints was carried out using XPS and infrared attenuated total reflectance (IRATR) spectroscopy. The oxygen plasma treatment for 1 min facilitated the migration of wax to the surface, which was transferred to the adhesive surface during the curing process. The increase in the length of the treatment up to 20 min produced a change in the Locus of Failure, which is mixed (adhesional in the oxidized rubber layer and cohesional in the wax layer). The oxygen plasma for 40 min produces a damaged oxidized rubber layer, which acts as a weak layer producing a decrease in peel strength and a cohesive Failure in that oxidized layer. Copyright © 2000 John Wiley & Sons, Ltd.
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Failure analysis of surface treated unvulcanized sbs rubber polyurethane adhesive joints
International Journal of Adhesion and Adhesives, 1997Co-Authors: Mercedes M Pastorblas, J M Martinmartinez, Rosa Torregrosamacia, John G DillardAbstract:Abstract The surface of an unvulcanized styrene-butadiene-styrene (SBS) rubber (S0) was chlorinated with 0.5–7wt% trichloroisocyanuric acid (TCI) solutions. The adhesion strength of surface-treated SO rubber/polyurethane adhesive joints was obtained from T-peel tests. The failed surfaces after peeling were characterized by ATR-IR spectroscopy, contact angle measurements, SEM coupled with EDX analysis and XPS. The untreated SO rubber shows no adhesion because of a lack of compatibility with the polyurethane adhesive. Chlorination of SO rubber with O.5wt% TCl produced a noticeable increase in T-peel strength which was due to the formation of CCl and CO species on the rubber surface, the Failure of the joint being produced at the chlorinated surface (weak boundary layer). Treatment of S0 rubber with greater concentrations of TCI, up to 2wt%, resulted in a decrease in the joint strength because the Locus of Failure was directed deeper into the chlorinated layer. On the other hand, the treatment of S0 rubber with 7wt% TCI produced different joint strength values in replicate joints that were tested under similar experimental conditions, mainly owing to differences in the Locus of Failure in the joints. Failure occurred randomly throughout the adhesive, the interface or the surface chlorinated layer.
