Influences of the joint and epoxy adhesive type on the CFRP-steel interfacial behavior

The mechanical behavior of an adhesive, in neat state and reinforced with up to 0.5 wt% of reduced graphene oxide (RGO) was investigated here. Tests were done at temperatures between the ambient temperature and the glass transition temperature ( Tg[Formula: see text] of the adhesive. Using a metal mold, cured plates of the neat and RGO reinforced epoxy adhesive were prepared. The adhesive powder and the bulk dumbbell-shaped specimens, obtained from cured adhesive plates, were subjected to differential scanning calorimetry (DSC) and tensile tests, respectively, to obtain the Tg as well as mechanical properties of the adhesives. The results indicated that adding RGO up to 0.5 wt% increased the glass transition temperature, the modulus of elasticity, and the strength of the adhesive. It was found that the presence of RGO reduced the adhesive’s strain at the break at the ambient temperature. However, at high temperatures, near the Tg, the ultimate strain of RGO-reinforced adhesives decreased slightly when compared to the ultimate strain of the neat specimens. This explains the reduction in toughness at ambient temperature obtained by adding RGO and the increase at high temperatures. Finally, the failure morphology of the neat and RGO-reinforced adhesive specimens was investigated using microscopic imaging of the specimens’ failure cross-sections, which supported and justified the experimental observations.

Download Full-text

Modeling of the Interfacial Behavior of $$\hbox {CO}_{2}$$ + $$\hbox {H}_{2}$$O and $$\hbox {H}_{2}$$S + $$\hbox {H}_{2}$$O with CPA EOS and Gradient Theory

International Journal of Thermophysics ◽

10.1007/s10765-021-02853-6 ◽

2021 ◽

Vol 42 (7) ◽

Author(s):

Fatemeh Biglar ◽

Ariel Hernández ◽

Shahin Khosharay

Keyword(s):

Gradient Theory ◽

Interfacial Behavior

Download Full-text

Influence of bismuth on microstructure, thermal properties, mechanical performance, and interfacial behavior of SAC305-xBi/Cu solder joints

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(21)65585-1 ◽

2021 ◽

Vol 31 (5) ◽

pp. 1397-1410

Author(s):

Suchart CHANTARAMANEE ◽

Phairote SUNGKHAPHAITOON

Keyword(s):

Thermal Properties ◽

Solder Joints ◽

Mechanical Performance ◽

Interfacial Behavior

Download Full-text

Formulation development and evaluation of drug-in-adhesive-type transdermal patch of metoclopramide HCl

Polymer Bulletin ◽

10.1007/s00289-021-03559-3 ◽

2021 ◽

Author(s):

Muhammad Suleman Imtiaz ◽

Muhammad Harris Shoaib ◽

Rabia Ismail Yousuf ◽

Fatima Ramzan Ali ◽

Muhammad Talha Saleem ◽

...

Keyword(s):

Transdermal Patch ◽

Formulation Development ◽

Adhesive Type

Download Full-text

Fabrication of Oil-in-Water Emulsions with Whey Protein Isolate–Puerarin Composites: Environmental Stability and Interfacial Behavior

Foods ◽

10.3390/foods10040705 ◽

2021 ◽

Vol 10 (4) ◽

pp. 705

Author(s):

Yejun Zhong ◽

Jincheng Zhao ◽

Taotao Dai ◽

Jiangping Ye ◽

Jianyong Wu ◽

...

Keyword(s):

Interfacial Tension ◽

Whey Protein ◽

Surface Protein ◽

Whey Protein Isolate ◽

Protein Isolate ◽

Environmental Stability ◽

Dependent Manner ◽

Emulsifying Properties ◽

Interfacial Behavior ◽

Concentration Dependent Manner

Protein–polyphenol interactions influence emulsifying properties in both directions. Puerarin (PUE) is an isoflavone that can promote the formation of heat-set gels with whey protein isolate (WPI) through hydrogen bonding. We examined whether PUE improves the emulsifying properties of WPI and the stabilities of the emulsions. We found that forming composites with PUE improves the emulsifying properties of WPI in a concentration-dependent manner. The optimal concentration is 0.5%, which is the highest PUE concentration that can be solubilized in water. The PUE not only decreased the droplet size of the emulsions, but also increased the surface charge by forming composites with the WPI. A 21 day storage test also showed that the maximum PUE concentration improved the emulsion stability the most. A PUE concentration of 0.5% improved the stability of the WPI emulsions against environmental stress, especially thermal treatment. Surface protein loads indicated more protein was adsorbed to the oil droplets, resulting in less interfacial WPI concentration due to an increase in specific surface areas. The use of PUE also decreased the interfacial tension of WPI at the oil–water interface. To conclude, PUE improves the emulsifying activity, storage, and environmental stability of WPI emulsions. This result might be related to the decreased interfacial tension of WPI–PUE composites.

Download Full-text

Fatigue behavior of adhesively bonded glass fiber reinforced plastic composites with different overlap lengths

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406214559111 ◽

2015 ◽

Vol 229 (7) ◽

pp. 1292-1299

Author(s):

E Kara ◽

A Kurşun ◽

MR Haboğlu ◽

HM Enginsoy ◽

H Aykul

Keyword(s):

Glass Fiber ◽

Fatigue Behavior ◽

Laminated Composite ◽

Element Model ◽

Treatment Method ◽

Epoxy Adhesive ◽

Lap Joints ◽

Adhesively Bonded ◽

Glass Fiber Reinforced Plastic ◽

Glass Fiber Reinforced

The joining techniques of lightweight and strong materials in the transport industry (e.g. automotive, aerospace, shipbuilding industries) are very important for the safety of the entire structure. In these industries, when compared with other joining methods, the use of adhesively bonded joints presents unique properties such as greater strength, design flexibility, and reduction in fuel consumption, all thanks to low weight. The aim of this study was the analysis of the tensile fatigue behavior of adhesively bonded glass fiber/epoxy laminated composite single-lap joints with three different specimen types including 30, 40 and 50 mm overlap lengths. In this study, composite adherents were manufactured via vacuum-assisted resin transfer molding and were bonded using Loctite 9461 A&B toughened epoxy adhesive. The effect of a surface treatment method on the bonding strength was considered and it led to an increment of about 40%. A numerical analysis based on a finite element model was performed to predict fatigue life curve, and the predicted results showed good agreement with the experimental investigation.

Download Full-text

β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH

Colloids and Interfaces ◽

10.3390/colloids5010014 ◽

2021 ◽

Vol 5 (1) ◽

pp. 14

Author(s):

Georgi G. Gochev ◽

Volodymyr I. Kovalchuk ◽

Eugene V. Aksenenko ◽

Valentin B. Fainerman ◽

Reinhard Miller

Keyword(s):

Theoretical Description ◽

Fluid Interfaces ◽

Interfacial Behavior ◽

Current State ◽

Air Interface ◽

Direct Measurements ◽

Wide Range ◽

Dilational Viscoelasticity ◽

Parameter Values ◽

Β Lactoglobulin

The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.

Download Full-text