Browse Topic: Adhesives and sealants

Items (1,827)
ABSTRACT A newly developed structural adhesive demonstrates a unique combination of high strength (43 ± 2 MPa) and displacement (4.7 ± 1.2 mm) in aluminum lap joint testing. Bulk material characterization of the prototype adhesive reveals its extreme ductility, with nearly 80% shear strain before failure and a 2.5-fold increase in strain energy density as compared to commercial structural adhesives. The prototype adhesive is found to maintain 67 to 82% of its initial strength under extreme environmental conditions, including at high temperatures (71°C), after high humidity (63°C hot water soak, 2 weeks), and after corrosive conditions (B117 salt spray, 1000 hours). The prototype structural adhesive is shown to also generate high strength bonds with multiple substrates, including steel, carbon fiber, and mixed material joints, while also providing galvanic isolation
Pollum, MarvinKriley, JosephNakajima, MasaTan, Kar TeanStalker, JeffreyFleischauer, RichardRearick, Brian
ABSTRACT Additions of both carbon fiber (CF) and carbon nano-tubes (CNTs) as reinforcements to polyurea (PUr) based adhesives are computationally investigated. Both CF and CNTs show an increase in stiffness. The effect of CF reinforcements on the PUr is more pronounced than the CNT’s but this due to CNT loading being dramatically lower. On percent basis the CNT effect on strength was greater than the CF. Increasing hard segment content of PUr also had a positive effect on the joint strength, but a negative effect on the shear joint displacement. Finally the addition of CF reinforcements moved the performance of a PUr formulation from a Group IV adhesive into the Group III category. This paper illustrates the potential for commonly available reinforcements to be used to tailor the strength elongation characteristic of a PUr adhesive system. Citation: Demetrios A. Tzelepis, Robert Hart, “Optimization of Nano-Enhanced Elastomeric Adhesives Through Combined Experimental and Computational
Tzelepis, Demetrios A.Hart, Robert
An industry-first 3D laser-based, computer-vision system can monitor and control the application of adhesive beads as tiny in width as two human hairs. This unique inspection system for electronic assemblies operates at speeds of 400 to 1,000 times per second, considerably quicker and more effective than conventional 2D systems. “Difficulty in precisely dispensing adhesives or sealants, especially in extremely small or complex electronic assemblies, can lead to over-application, under-application, bubbles, or incorrect location of the adhesive bead,” Juergen Dennig, president of Ann Arbor, Michigan-headquartered Coherix, told SAE Media. Improper application of joining material on electronic control units (ECUs) and power control units (PCUs) can result in poor adhesion, material voids and short circuits
Buchholz, Kami
The purpose of air conditioning (AC) duct packing is multifaceted, serving to prevent condensation, eliminate rattle noise, and provide thermal insulation. A critical aspect of duct packing is its adhesive quality, which is essential for maintaining the longevity and effectiveness of the packing's functions. Indeed, the challenge of achieving adequate adhesivity on AC ducting parts is significant due to the harsh operating conditions to which these components are subjected. The high temperatures and presence of condensation within the AC system can severely compromise the adhesive's ability to maintain a strong bond. Moreover, the materials used for these parts, such as HDPE, often have low surface energy, which further hinders the formation of a durable adhesive bond. The failure of the adhesive under these conditions can lead to delamination of the duct packing, which can result in customer inconvenience due to rattling noises, potential electrical failures if condensed water
M, Amala RajeshSonkar, SurabhiKumar, Mukesh
Military performance requirements for adhesives have been traditionally derived to fulfill niche defense needs in harsh operational environments with little consideration for dual-use commercial potential. U.S. Army Research Laboratory, Aberdeen, MD The term “military-grade” can have a variety of meanings that are perspective dependent. In 2014, Ford Motor Company emphasized the term heavily in advertising campaigns to garner consumer acceptance for the transition from steel to aluminum in the body of their flagship F150 model. As cited by Ford, “Engineers selected these high-strength, military-grade aluminum alloys because of the metals' unique ability to withstand tough customer demands.” From this point-of-view, military-grade implies superior performance. However, the bureaucratic and logistical barriers required for certification to military-grade acceptance levels per DoD performance requirements can also be perceived as impediments to innovation and the transition of fundamental
The term “military-grade” can have a variety of meanings that are perspective dependent. In 2014, Ford Motor Company emphasized the term heavily in advertising campaigns to garner consumer acceptance for the transition from steel to aluminum in the body of their flagship F150 model. As cited by Ford, “Engineers selected these high-strength, military-grade aluminum alloys because of the metals’ unique ability to withstand tough customer demands.” From this point-of-view, military-grade implies superior performance. However, the bureaucratic and logistical barriers required for certification to military-grade acceptance levels per DoD performance requirements can also be perceived as impediments to innovation and the transition of fundamental science into tangible product. This is in-part due to the legacy age of many DoD performance standards dating to the 1950s and 1960s when the US military peaked in technology market share and was responsible for approximately two-thirds of domestic
As aerospace engineers push the boundaries of new frontiers, the need for advanced materials that can withstand the rigorous demands of these advanced applications is relentless. These materials go beyond functionality; it is about ensuring reliability in the skies, where failure is not an option. Fluorosilicone can help do exactly that. In the 1960s, the U.S. Air Force noticed that conventional silicone-based sealants, coatings, and other components degraded rapidly when exposed to fuels, de-icing fluids, and other hydrocarbon-based solvents. Dimethyl-based silicones are non-polar and easily absorb hydrocarbon-based solvents, which may result in material swelling, mechanical weakening, and ultimately, failure
This specification covers polythioether rubber fuel-resistant sealing compounds supplied as a two-component system that cures at room temperature
AMS G9 Aerospace Sealing Committee
This standard describes the accepted methods used for preparing aerospace sealant test specimens for qualification and quality conformance or acceptance testing. AS5127/1 and AS5127/2 are to be used in conjunction with this document and the applicable AMS specifications
AMS G9 Aerospace Sealing Committee
For decades, people with diabetes have relied on finger pricks to withdraw blood or adhesive microneedles to measure and manage their glucose levels. In addition to being painful, these methods can cause itching, inflammation and infection
A research team from Kyushu University, in collaboration with Japanese company Nitto Denko, has developed a tape that can be used to stick 2D materials to many different surfaces, in an easy and user-friendly way
In research that may lead to advancements in the design of next-generation airplane and spacecraft, MIT engineers used carbon nanotubes to prevent cracking in multilayered composites. Massachusetts Institute of Technology, Cambridge, MA To save on fuel and reduce aircraft emissions, engineers are looking to build lighter, stronger airplanes out of advanced composites. These engineered materials are made from high-performance fibers that are embedded in polymer sheets. The sheets can be stacked and pressed into one multilayered material and made into extremely lightweight and durable structures. But composite materials have one main vulnerability: the space between layers, which is typically filled with polymer “glue” to bond the layers together. In the event of an impact or strike, cracks can easily spread between layers and weaken the material, even though there may be no visible damage to the layers themselves. Over time, as these hidden cracks spread between layers, the composite
This specification covers a polysulfide sealing compound with low adhesive strength, supplied as a two-component system that cures at room temperature
AMS G9 Aerospace Sealing Committee
This SAE Aerospace Standard (AS) establishes standard requirements for aerospace sealants and adhesion promoters, which may be incorporated as part of SAE Aerospace Material Specifications (AMS) for such products. This document provides for commonality of methods and procedures for responsibility for inspection, source inspection, classification of tests, establishment of/and qualification to qualified products lists, approval, reports, resampling and retesting, packaging, and marking
AMS G9 Aerospace Sealing Committee
This study focused on the synthesis and characterization of monodisperse spherical TiO2 nanoparticles doped on the surface with Se (IV) in order to increase the mechanical properties of the bonded joint reinforcing. Work will begin with the synthesis of monodisperse quasi-spherical TiO2 nanoparticles with a modal diameter of less than 20 nm, using the sol-gel technique. Se (IV) selenium surface doping changed the specimen’s chemistry and physics. Different initial concentrations of the doping element will be tested. Next, a physicochemical characterization of the different solid systems will be carried out in order to determine the effect of the doping element on the properties of titanium dioxide. Their morphology and size will be studied through transmission electron microscope observations; volume chemical composition by X-ray diffraction analysis, EDX (energy-dispersive X-ray), and XRF (X-ray fluorescence). The careful selection of 4% and 6% concentrations produced the optimum
Hadjez, FayssalMaouche, HichemBoumediri, HaithemChorfi, SofianeBoukelia, Taqiy Eddine
This specification covers fuel-resistant polysulfide (T) sealing compounds supplied as a two-component system
AMS G9 Aerospace Sealing Committee
Automotive body structures are being increasingly made in multi-material system consisting of steel, aluminum (Al) and fiber-reinforced plastics (FRP). Therefore, many joining techniques such as self-piercing riveting (SPR) and adhesive bonding have been developed. On the other hand, OEMs want to minimize the number of joining techniques to reduce the manufacturing complexity. Amount all joining methods, resistance spot welding (RSW) is the most advanced and cost-effective one for body-in-white. However, RSW cannot be applied for joining dissimilar materials. Therefore, a novel Rivet Resistance Spot Welding method (RRSW) was developed in which Al or FRP components can be directly welded to steel structures with existing welding systems. RRSW uses rivet-like double T-shaped steel elements as a welding adapter which are formed or integrated into Al or FRP components during their forming process. After that, they are welded to the steel components by RSW. This paper shows at first the
Fang, XiangfanZhang, FanXu, Hongli
A team has developed medical adhesives that are not only safe for human use but also customizable for different organs. The researchers used mussel-derived adhesive proteins to develop customized underwater bio-adhesive patches (CUBAP
Adhesively bonded joints have been applied in the automotive industry for the past few decades due to their advantages such as higher fatigue resistance, light weight, capability of joining dissimilar materials, good energy absorption, and high torsional stiffness for overall body structure. They also provide an effective seal against noise and vibration at a low cost. There exists the challenge of defining the fatigue characteristics of adhesive joints under cyclic loading conditions, and conventional methods have limitations in detecting the crack initiation of a bonded joint. This study introduces a method of detecting crack initiation by using the frequency method. It is found that stiffness change in the system is highly correlated to change in natural frequencies. By monitoring the change in natural frequencies, the crack initiation can be detected
Huang, XiaobaoBarber, Gary
In the aerospace industry, large aircrafts employ composite materials for making complex structures which not only reduces weight and cost but also reduces the number of joints. Irrespective of that joining of structures cannot be avoided and for that mechanical fasteners such as rivets and bolts are employed along with adhesive bonding. Further, in recent years natural fibers have been studied extensively for their numerous advantages and have already been made into several automotive applications. Keeping these current trends in mind an attempt is made to investigate the joining behavior of natural fiber composites experimentally. So in this study, the ultimate failure load, bearing strength and the dominating failure mode of jute-hemp fabric-reinforced polymeric composites joined using single and double-bolted configurations are studied. The polymeric composite laminates were successfully fabricated using resin infusion technique and test specimens were fabricated following ASTM
Koppad, PraveennathChinnakurli Suryanarayana, RameshReddy, NagarajaSethuram, D
Researchers at the EPFL have achieved a breakthrough in the treatment of tracheomalacia, a condition characterized by weak tracheal cartilage and muscles that normally keep the airway open for proper breathing. The team, composed of EPFL engineers and CHUV pediatric airway surgeons, has successfully developed a novel adhesive hydrogel patch that can effectively alleviate tracheomalacia, providing hope for improved treatment options for this challenging condition. The proof of concept was recently published in iScience
Epoxy polymers are widely used in various industries, e.g., as coatings, adhesives, and for lightweight construction due to their unique properties such as high strength, chemical resistance, and adhesion to various surfaces. Therefore, one of the most prominent applications is their use as matrix material in fiber-reinforced composites, which are heavily employed in the aerospace sector. However, the disposal of epoxy polymers and composites thereof has become a significant concern due to their recalcitrant nature and the adverse environmental effects caused by traditional recycling methods
Composites are especially important for the development and implementation of sustainable technologies such as wind power, energy-efficient aircrafts, and electric cars. Despite their advantages, their non-biodegradability raises challenges for the recycling of polymer and composites in particular. University of Hamburg, Hamburg, Germany Epoxy polymers are widely used in various industries, e.g., as coatings, adhesives, and for lightweight construction due to their unique properties such as high strength, chemical resistance, and adhesion to various surfaces. Therefore, one of the most prominent applications is their use as matrix material in fiber-reinforced composites, which are heavily employed in the aerospace sector. However, the disposal of epoxy polymers and composites thereof has become a significant concern due to their recalcitrant nature and the adverse environmental effects caused by traditional recycling methods. In this context, the overall production of plastic waste is
Ultrasonic Testing (UT) is a typical Non-destructive testing (NDT) method for examining the structural components for aircraft production. Manufacturing aircraft made of fiber metal laminates (FML) includes cascaded steps such as placement of aluminum, glass prepreg, adhesive, doublers, stringers, vacuum bagging and curing in an autoclave. Quality control (QC) is performed first at the layup of the component (without stringers) after curing and the quality assessment is visually evaluated. The manually performed examination of anomalies is very time-consuming. In addition, conducted NDT inspection using a manual UT phased array for Glass Reinforced (GLARE®) FML of A380, it lacked the high capacity of data and additionally an evaluation software
This specification establishes the requirements for a polysulfide sealing compound in putty consistency to be used for form-in-place sealing of removable doors, skins, and panels
AMS G9 Aerospace Sealing Committee
This paper presents the adhesion strength of ice on sanded and machine-finished aluminum test coupons as measured using the National Research Council of Canada (NRC) Altitude Icing Wind Tunnel (AIWT) spin rig. This rig is used to evaluate commercial and internally-developed coatings for low-adhesion properties, and the performance of ice on aluminum is required as a baseline to compare the coatings against. The tests are performed over a range of aerodynamic and icing cloud conditions, including variations in static air temperature and exposure time (and therefore accumulated ice mass). The data analysis includes an evaluation of the uncertainty in the results based on the measured ice mass repeatability and the measured shear stress repeatability. The results show the adhesive shear stress of ice, generated with a 20 μm icing cloud at a true airspeed of 80 m/s and a static air temperature of -20°C to create rime ice conditions, is 682 kPa (±13%) for aluminum coupons with a sanded
Clark, Catherine
Ice adhesion characterization relies heavily on experimental data, especially when dealing with fracture parameters. In this paper, a complementary framework encompassing experimental testing with the numerical treatment of the fracture variables is proposed to provide a physical description of adhesive fracture propagation at the interface of an iced structure. The tests are based on a quasi-static flexural testing setup composed of a displacement-driven actuator and an iced plate. The measured crack length and plate deflection provide the data to be analyzed by the Virtual Crack Closure Technique in order to approximate the critical energy release rate required to study adhesive fracture propagation. The critical energy release rate in mode II is under-predicted and its value is approximated using its counterpart in mode I. The Cohesive Zone Model is then implemented to assess adhesive fracture propagation using a bi-linear traction-displacement law with the calculated fracture
Riera, PauPothin, Jason RaphaëlPommier-Budinger, ValérieBudinger, MarcLachaud, FrédéricRoberts, Ian
This document provides a method/procedure for specifying the properties of vulcanized elastomeric materials (natural rubber or synthetic rubbers, alone or in combination) that are intended for, but not limited to, use in rubber products for automotive applications. This document covers materials that do not contain any re-use, recycled, or regrind materials unless otherwise agreed to by manufacturer and end user. The use of such materials, including maximum percent, must be specified using a “Z” suffix. This classification system covers thermoset High Consistency Elastomers (HCEs) only. Thermoplastic Elastomer (TPE) materials are classified using SAE J2558. Silicone Formed In Place Gasket (FIPG) systems such as Room Temperature Vulcanized (RTV) Silicones, and Liquid Silicone Rubber (LSR) systems are classified using ASTM F2468
Committee on Automotive Rubber Specs
Most electronic devices aren’t waterproof, much to your irritation if a sprinkler suddenly sprays you while you’re talking outside on your cellphone. Some electronics can be made at least water-resistant by, for example, using special glues to fuse outer components together. Flexible electronics are another story. Their sealant materials must be able to bend, yet with current technology it’s inevitable that eventually such a sealant will crack or separate from the device — and there goes your water-resistant coating
This specification covers six types of silicone sealing compounds as either one-part or two-part systems that cure at room temperature
AMS G9 Aerospace Sealing Committee
This specification covers two types of two-component, epoxy, chemical and solvent resistant primer coatings formulated primarily for spray application. These coatings are compatible with epoxy and polyurethane topcoats
AMS G8 Aerospace Organic Coatings Committee
An injectable biomaterial with significantly improved adhesive strength, stretchability, and toughness could enable improved surgical sealing. This chemically modified, gelatin-based hydrogel has attractive features, including rapid gelation at room temperature and tunable levels of adhesion. This custom-engineered biomaterial is ideal as a surgical wound sealant, with its controllable adhesion and injectability and its superior adherence to a variety of tissue and organ surfaces
Trends in wearable technology follow those of the broader biomedical and electronics industries — devices are getting smaller, smarter, and easier to use. Specifically, wearables in healthcare have moved toward solutions that reduce the device profile, provide more integration with smartphone apps, and most importantly enable patients to receive their treatments at home, outside of a doctor’s visit. These wearable devices range from on-body drug-delivery systems for cancer treatment to electrical nerve stimulation patches or simply sensors to monitor vitals. All treatments increase patient autonomy and are rapidly increasing in popularity
This standard covers the general requirements and methods for testing sandwich core materials and for testing sandwich construction of the types used primarily in aircraft structures. This standard does not include test methods applicable only to a specific product; such test methods are included in the detailed specifications for the product
AMS P17 Polymer Matrix Composites Committee
Premium instrument panels (IPs) contain passenger airbag (PAB) systems that are typically comprised of a stiff plastic substrate and a soft ‘skin’ material which are adhesively bonded. During airbag deployment, the skin tears along the scored edges of the door holding the PAB system, the door opens, and the airbag inflates to protect the occupant. To accurately simulate the PAB deployment dynamics during a crash event all components of the instrument panel and the PAB system, including the skin, must be included in the model. It has been recognized that the material characterization and modeling of the skin tearing behavior are critical for predicting the timing and inflation kinematics of the airbag. Even so, limited data exists in the literature for skin material properties at hot and cold temperatures and at the strain rates created during the airbag deployment. This paper presents tensile test results of one typical skin material conducted at four different strain rates of 0.01/s
G, KarthiganSavic, VesnaHu, SiboRavichandran, GowrishankarTripathy, Biswajit
Battery Electric Vehicles (BEVs) are becoming more competitive day by day to achieve maximum peak power and energy requirement. This poses challenges to the design of Thermal Interface Material (TIM) which maintains the cell temperature and ensure retention of cell and prevent electrolyte leak under different crash loads. TIM can be in the form of adhesives, gels, gap fillers. In this paper, TIM is considered as structural, and requires design balance with respect to thermal and mechanical requirements. Improving structural strength of TIM will have negative impact on its thermal conductivity; hence due care needs to be taken to determine optimal strength that meets both structural and thermal performance. During various crash conditions, due to large inertial force of cell and module assembly, TIM is undertaking significant loads on tensile and shear directions. LS-DYNA® is used as simulation solver for performing crash loading conditions and evaluate structural integrity of TIM
Seshadri, Srirambhavsar, TejasR, NarayanaGH, Shivaprakash
Researchers have developed a portable sensor made of simple materials to detect heavy metals in sweat, which is easily sampled. The sensor is simple in terms of the materials used to make it and the stages of its production. The base of the device is polyethylene terephthalate (PET), on top of which is a conductive flexible copper adhesive tape with the sensor printed on it, and a protective layer of nail varnish or spray. The exposed copper is removed by immersion in ferric chloride solution for 20 minutes, followed by washing in distilled water to promote the necessary corrosion
While there are various types of Fuel Cell architectures being developed, the focus of this document is on Proton Exchange Membrane (PEM) fuel cell stacks and ancillary components for automotive propulsion applications. Within the boundaries of this document are the: Fuel Supply and Storage, Fuel Processor, Fuel Cell Stack, and Balance of Plant, as shown in Figure 1
Fuel Cell Standards Committee
This specification covers polyurethane (PUR) in the form of two-component sealing compounds
AMS G9 Aerospace Sealing Committee
This SAE Aerospace Standard (AS) establishes standard requirements for aerospace sealants and adhesion promoters, which may be incorporated as part of SAE Aerospace Material Specifications (AMS) for such products. This document provides for commonality of methods and procedures for responsibility for inspection, source inspection, classification of tests, establishment of/and qualification to qualified products lists, approval, reports, resampling and retesting, packaging, and marking
AMS G9 Aerospace Sealing Committee
This specification covers two types of electrically conductive, elastomeric polythioether sealing compounds that cure at room temperature. The sealing compound is supplied as either a two-component system or as premixed and frozen
AMS G9 Aerospace Sealing Committee
This specification covers fuel-resistant, two-component polysulfide synthetic rubber compounds which cure at room temperature
AMS G9 Aerospace Sealing Committee
This SAE Aerospace Recommended Practice (ARP) contains guidance to assist users by providing a method to install an AS6224/2 repair sleeve
AE-8C2 Terminating Devices and Tooling Committee
This specification covers the requirements for adhesives in film form for bonding metal facings to metal cores and to metal components of sandwich panels which are intended for use in primary and secondary structural airframe parts that may be exposed to temperatures up to 500°F (260°C
AMS P17 Polymer Matrix Composites Committee
This specification covers a prepolymer in the form of an epoxy cresol novolac (ECN) resin
AMS P17 Polymer Matrix Composites Committee
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