Bonding Agents and Adhesives: Reactor Response

1988 ◽  
Vol 2 (1) ◽  
pp. 155-157 ◽  
Author(s):  
R.L. Bowen
Keyword(s):  
Composite Materials ◽  
Dimensional Stability ◽  
Adhesive Bonding ◽  
Stress Concentrations ◽  
Multiple Bonds ◽  
Bonding Agents ◽  
Restorative Materials ◽  
Adhesive Materials

Adhesive materials must form multiple bonds with sound tooth substrates for maximum adhesion. Adhesive resins can be applied in incremental layers to bond composite materials to enamel and dentin. Hardening shrinkage and stress concentrations are factors that have detrimental effects on adhesive bonding with resins and composites. Improvements in dimensional stability of composites can therefore allow for better bonding and sealing of preventive and restorative materials.

Review on the Fatigue of Composite Hybrid Joints Used in Aircraft Structures

2014 ◽  
Vol 891-892 ◽  
pp. 1591-1596 ◽  
Author(s):  
Nabil Chowdhury ◽  
Wing Kong Chiu ◽  
John Wang
Keyword(s):  
Composite Materials ◽  
Composite Laminates ◽  
Adhesive Bonding ◽  
High Stress ◽  
Real Life ◽  
Engineering Industry ◽  
Stress Concentrations ◽  
Static Testing ◽  
Hybrid Joints ◽  
Mechanical Fastening

The use of composite materials as a replacement for commonly used metals such as aluminium and steel are increasing in the engineering industry, particularly in the aerospace sector. The move towards light weight and high stiffness structures that have good fatigue durability and corrosion resistance has led to the rapid move from metal to composites. This change allows for further flexibility in design and fabrication of various components and joints. There are three main categories of joints used in composite materials – mechanically fastened joints, adhesively bonded joints and the combination of the two called hybrid joints. In order to adequately understand the effectiveness of these joints, substantial testing and validation is required, particularly in the use of hybrid joints for real life applications. Static testing, load distribution and parametric studies of hybrid joints have been investigated by various researchers; however further work is still required in understanding the durability and fatigue of hybrid joints and ensuring that both the adhesive and mechanical fasteners can work together effectively in producing an optimum joint. Mechanical fastening alone in composite laminates is not a preferred joining method as they create high stress concentrations around the fastener holes. Adhesive bonding although has numerous benefits it is difficult to detect the bond defect particularly in cases where weak bonds can occur during applications and it is sensitive towards the environmental conditions. Thus hybrid joints are seen arguably as being more effective in joining composite components together and offer greater residual strength. Hence the performance, strength and long-term durability of these joints need to be further investigated and be applied to practical situations whilst assisting in repair certification.

scholarly journals Defects and uncertainties of adhesively bonded composite joints

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Sadik Omairey ◽  
Nithin Jayasree ◽  
Mihalis Kazilas
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Production Efficiency ◽  
Adhesive Bonding ◽  
Detection Methods ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Wide Range ◽  
Bonded Composite

AbstractThe increasing use of fibre reinforced polymer composite materials in a wide range of applications increases the use of similar and dissimilar joints. Traditional joining methods such as welding, mechanical fastening and riveting are challenging in composites due to their material properties, heterogeneous nature, and layup configuration. Adhesive bonding allows flexibility in materials selection and offers improved production efficiency from product design and manufacture to final assembly, enabling cost reduction. However, the performance of adhesively bonded composite structures cannot be fully verified by inspection and testing due to the unforeseen nature of defects and manufacturing uncertainties presented in this joining method. These uncertainties can manifest as kissing bonds, porosity and voids in the adhesive. As a result, the use of adhesively bonded joints is often constrained by conservative certification requirements, limiting the potential of composite materials in weight reduction, cost-saving, and performance. There is a need to identify these uncertainties and understand their effect when designing these adhesively bonded joints. This article aims to report and categorise these uncertainties, offering the reader a reliable and inclusive source to conduct further research, such as the development of probabilistic reliability-based design optimisation, sensitivity analysis, defect detection methods and process development.

scholarly journals A FULL-SCALE STUDY OF THE STRENGTH OF MASSIVE WOOD GLUING WITH MODERN ADHESIVES WHEN OPERATING IN VARIOUS CONDITIONS

2020 ◽  
Vol 10 (1) ◽  
pp. 105-115
Author(s):  
Larisa Ponomarenko ◽  
Ekaterina Kantieva ◽  
Maksim Posluhaev ◽  
Aleksandr Chernyshev
Keyword(s):  
Bonding Strength ◽  
Polyvinyl Acetate ◽  
Adhesive Bonding ◽  
Adhesive Layer ◽  
Correct Choice ◽  
Operating Conditions ◽  
Furniture Manufacturing ◽  
Wooden House ◽  
House Building ◽  
Adhesive Materials

Abstract Glues are widely used to connect various materials, especially since in some cases other options for combining materials are not suitable. The paper deals with the bonding of solid hardwood with modern adhesive materials. Currently, a large group of adhesives of various brands from Russian and foreign manufacturers is presented on the market. In the woodworking industry, adhesives are used in the carpentry and furniture, manufacturing, in wooden house-building, in the production of finishing materials, etc., which are operated outside and inside the premises in constant and variable humidity conditions. Therefore, the correct choice of adhesives plays an important role both for the manufacturer and subsequently for the consumer of the resulting product. In this work, we have studied the dependence of the tensile strength when chipping along the adhesive layer on the type of glue, wood species, and operating conditions. We have selected the following adhesives based on polychloroprene, polyvinyl acetate and rubber. The greatest strength of the adhesive bonding when gluing solid hardwood is given by polyvinyl acetate adhesives. When using the product in conditions of changing temperature and humidity, the bonding strength decreases, in some cases significantly. In fairness, it should be noted that not only the type of glue, but also the type of wood affects the bonding strength

scholarly journals Surface toughening – An industrial approach to increase the robustness of pure adhesive joints with film adhesives

2020 ◽  
Vol 234 (13) ◽  
pp. 1980-1987
Author(s):  
MJ Schollerer ◽  
J Kosmann ◽  
D Holzhüter ◽  
C Bello-Larroche ◽  
C Hühne
Keyword(s):  
Large Scale ◽  
Adhesive Bonding ◽  
Bolted Joints ◽  
Small Scale ◽  
Bonded Joints ◽  
Fiber Reinforced ◽  
Load Path ◽  
Stress Concentrations ◽  
Manufacturing Defects ◽  
Wide Range

Bonding is known for its wide range of advantages over bolted joints when joining different materials together. However, the advantages e.g. of homogeneous load distribution can quickly be lost in case of overload. For this reason, the load occurring in the adhesive is reduced by constructive measures far below the yield stress of the adhesive, which leads to a conservative joint design. And to be on the safe side, a few “chicken rivets” are then placed again. This problem is particularly well known in aviation. Highly loaded components are structurally bonded by a combination of rivets and adhesive in order to underline the advantages of structural adhesive bonding with the safety of the well-known bolted joints. Known as fail-safe design, this concept is damage tolerant and more robust against manufacturing defects through a secured double load path.  Especially when joining fiber-reinforced composites, bolts weaken the adherends of the joint and only contribute to load transfer when the brittle adhesive fails. With the help of Surface Toughening, a boltless technique for reducing stress concentrations and arresting cracks in adhesive bonded joints is available. This work describes the industrial application of this technique. Starting with coupon tests and a small scale demonstrator to ensure the compatibility with industrial manufacturing processes, such as infusion and prepreg manufacturing, a large scale demonstrator of a 2 m carbon fiber reinforced plastic (CFRP) - HTP leading edge with hybrid laminar flow control is manufactured by the industrial partner AERnnova. Verifying a simple and cost-effective application of the technology, Surface Toughening enables robust bonded joints with a minimum impact on today's process of adhesive bonding.

scholarly journals Radiopacity evaluation of composite restorative resins and bonding agents using digital and film x-ray systems

2012 ◽  
Vol 06 (02) ◽  
pp. 115-122 ◽  
Author(s):  
Bengi Oztas ◽  
Sebnem Kursun ◽  
Gul Dinc ◽  
Kıvanc Kamburoglu
Keyword(s):  
Composite Materials ◽  
In Vitro Study ◽  
Composite Resins ◽  
Human Tooth ◽  
Dental Resin ◽  
Bonding Agents ◽  
Dentin Bonding ◽  
Dentin Bonding Agents ◽  
Phosphor Plates

ABSTRACTObjective: The purpose of this in vitro study was to explore the radiopacity of composite resins and bonding materials using film and phosphor plates.Methods: Nine composite dental resin specimens and human tooth slices were exposed together with an aluminium stepwedge using dental film and phosphor plates. Eight dentin bonding specimens were prepared and exposed in a similar manner. Their radiopacity on film was assessed using a transmission densitometer, and the radiopacity with phosphor plates was assessed digitally using the system’s own software (Digora). Data were analysed using one-way analysis of variance (ANOVA) and post-hoc Tukey tests (P<.05). Film and phosphor plate radiopacity values were compared using simple regression analysisResults: Excellent linear correlation was found between film and phosphor plates for both composite resins and bonding agents. The composite materials Spectrum Tph and Natural Look exhibited the highest radiopacity with film and with phosphor plates, respectively. All the dentin bonding agents tested exhibited lower radiopacity than dentin. Conclusion: Synergy, Ice, Filtek Silorane, Filtek Z250, Clearfil Majesty Posterior, Herculite Classic, Spectrum Tph, and Natural Look composite materials exhibited greater radiopacity than dentin, and all the dentin bonding agents tested exhibited lower radiopacity than either enamel or dentin. (Eur J Dent 2012;6:115-122)

Stresses in a composite material with a single broken fibre

1967 ◽  
Vol 2 (3) ◽  
pp. 239-245 ◽  
Author(s):  
M J Iremonger ◽  
W G Wood
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Material ◽  
Composite Materials ◽  
High Stress ◽  
The Finite Element Method ◽  
Stress Concentrations ◽  
Lower Stress ◽  
Fibre Break ◽  
Matrix Yielding

An investigation has been made into the suitability of the finite-element method for studying the stresses in composite materials and the case of a single broken fibre in a matrix has been examined. It has been found that high stress concentrations occur in the region of the fibre break which increase with decreasing end gap and would cause matrix yielding or fracture at comparatively low overall stresses. When the end gap is not void but filled with matrix much lower stress concentrations occur which, below a certain value of end gap, actually decrease as the gap is made smaller.

scholarly journals Dentin Bond Integrity of Hydroxyapatite Containing Resin Adhesive Enhanced with Graphene Oxide Nano-Particles—An SEM, EDX, Micro-Raman, and Microtensile Bond Strength Study

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2978
Author(s):  
Yasser F. AlFawaz ◽  
Basil Almutairi ◽  
Hiba F Kattan ◽  
Muhammad S. Zafar ◽  
Imran Farooq ◽  
...  
Keyword(s):  
Bond Strength ◽  
Adhesive Bonding ◽  
Nano Particles ◽  
Microtensile Bond Strength ◽  
Adhesive Resin ◽  
Bonding Agents ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Interaction Control ◽  
Uniform Dispersion

The aim was to synthesize and characterize an adhesive incorporating HA and GO nanoparticles. Techniques including scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), micro-tensile bond strength (μTBS), and micro-Raman spectroscopy were employed to investigate bond durability, presence of nanoparticles inside adhesive, and dentin interaction. Control experimental adhesive (CEA) was synthesized with 5 wt% HA. GO particles were fabricated and added to CEA at 0.5 wt% (HA-GO-0.5%) and 2 wt% GO (HA-GO-2%). Teeth were prepared to produce bonded specimens using the three adhesive bonding agents for assessment of μTBS, with and without thermocycling (TC). The adhesives were applied twice on the dentin with a micro-brush followed by air thinning and photo-polymerization. The HA and GO nanoparticles demonstrated uniform dispersion inside adhesive. Resin tags with varying depths were observed on SEM micrographs. The EDX mapping revealed the presence of carbon (C), calcium (Ca), and phosphorus (P) in the two GO adhesives. For both TC and NTC samples, HA-GO-2% had higher μTBS and durability, followed by HA-GO-0.5%. The representative micro-Raman spectra demonstrated D and G bands for nano-GO particles containing adhesives. HA-GO-2% group demonstrated uniform diffusion in adhesive, higher μTBS, adequate durability, and comparable resin tag development to controls.

The Influence of Non-Traditional Composite Laminates on Open-Hole Tension Strength

2007 ◽  
Author(s):  
D. P. Stone ◽  
L. V. Smith ◽  
A. Kothidar
Keyword(s):  
Strain Field ◽  
Composite Laminates ◽  
Damage Evolution ◽  
Adhesive Bonding ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Strain Measurements ◽  
Stress Risers ◽  
Open Hole ◽  
Increased Strength

Composite materials are commonly used in applications with a need for increased strength or reduced weight. The composite structure is often attached using mechanical fasteners, even in cases where adhesive bonding is prevalent. The strength of the composite is typically reduced by large factors in the presence of these stress risers. The following considers the sensitivity of non-traditional layups to stress concentrations in the form of open-hole tension. The effects are described numerically and experimentally using finite element analysis and spatial strain measurements, respectively. Improvements in strength exceeding 10% from this preliminary exercise suggest that tailoring fiber orientations may have potential to minimize the effect of stress concentrations. Consideration of the strain field in the vicinity of the hole showed evidence of damage evolution within approximately 25% UTS for many of the laminates. The maximum strain failure criterion was able to describe the onset of damage or yield for the laminates considered here.

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