Adhesives and Adhesion Technologies: A Critical Review

Bharti, Srijita

doi:10.11648/j.ajpst.20180401.13

Cited by 4 publications

(3 citation statements)

References 25 publications

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Section: Introductionmentioning

confidence: 99%

“…Plasma treatments offer an alternative method to prepare surfaces of carbon fiber composites for bonding and possess several advantages over traditional mechanical and chemical approaches. , Atmospheric and low-pressure plasma discharges produce high-energy ions and reactive radicals that interact with composites to change the micrometer-scale morphology and chemical functions of the surface with minimal impact on the integrity of the bulk structure. , These plasma treatments may obviate the use of organic solvents, reduce ergonomic impact on operators, and may improve success and reproducibility of adhesion. Seminal work in this area demonstrated that an atmospheric-pressure O 2 discharge introduces multiple forms of oxygenated functions to the surface of carbon fiber composites (manufactured from Nelcote E765 epoxy and AS4 PAN-based carbon fibers), and the interfacial adhesion strength correlated with the coverage of carboxylic acid surface functions, which were determined by lap shear tests and X-ray photoelectron spectroscopy (XPS), respectively. , The authors attributed these changes to chemical bonds formed between these carboxylic acid groups and epoxide functions within the adhesive.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Oxygen Plasma Treatments on Surface Functional Groups and Shear Strength of Carbon Fiber Composites

Zhang

Wilson

Kitt

et al. 2021

ACS Appl. Polym. Mater.

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The morphology and chemical function of surfaces strongly influence adhesion at interfaces within carbon fiber composites (i.e., carbon fiber-reinforced polymer) and the mechanical strength of the composite materials. Reactive plasma discharges modify these properties of composite surfaces and can improve adhesion. However, the outcome depends upon the specific composite–adhesive used, which is likely due to a subtle difference in the formulation of these components. Here, we select a model system widely used for aerospace applications (T300 composites formed by the combination of T300 fiber, Cycom 934 epoxy resin, and FM377 adhesives) to investigate the influence of oxygen (O2) plasma treatments on the topology and chemistry of composite surfaces and the differences in mechanical strengths correlated to these changes. Lap shear tests show that shear strengths increase by 10% because of low-pressure O2 plasma treatments. These plasma treatments increase surface roughness by 2-fold, which may improve mechanical modes of interlocking at composite–adhesive interfaces. Chemical analysis of composite surfaces by X-ray photoelectron spectroscopy (XPS) shows that treated composites expose a greater number of imide moieties (N 1s binding energies near 400.7 eV), and reactive titrations with fluorescent probe molecules corroborate these results. The differences in the surface coverage of imide groups strongly correlate with the shear strength of these composites, and both increase with the power and time of the O2 plasma treatment, which is presumably due to greater cumulative exposure to reactive oxygen species. The imide functions that promote adhesion likely form by the oxidation of aniline derivatives present in the T300 composite, and we propose that these functions form covalent bonds with epoxides within the adhesives to improve interfacial chemical bonding. These findings suggest that O2 plasmas increase both mechanical interlocking and interfacial chemical bonding and thus provide greater shear strengths for carbon fiber composites.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Oxygen Plasma Treatments on Surface Functional Groups and Shear Strength of Carbon Fiber Composites

Zhang

Wilson

Kitt

et al. 2021

ACS Appl. Polym. Mater.

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“…A adesão é um fenômeno como objetivo de unir componentes, sendo de grande interesse em todas as áreas do conhecimento, inclusive a biomédica, que contribui para conferir resistência, biomateriais com adesividade apropriadas para a aplicação desejada, substituindo técnicas tradicionais de fixação mecânica, melhorando o processo de cicatrização e diminuição nas trocas. Curativos com excelente aderência à base da lesão de pele ou em determinados tipos de feridas possibilita a não contaminação externa e perda de líquidos, que favorecem o processo de cicatrização e promove a redução da necessidade de substituição dos curativos (Bharti, 2018;Pereira et al, 2019).…”

Section: Introductionunclassified

Modelagem da viscosidade em mistura polivinilpirrolidona/quitosana para processamento de membrana adesiva

Paiva

Filho

Santos

et al. 2021

RSD

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Os biopolímeros polivinilpirrolidona e quitosana são biomateriais utilizados no tratamento de feridas, devido suas propriedades biológicas, físico-química entre outras, além de sua processabilidade. O controle da viscosidade dos polímeros é de fundamental importância para o processamento e consequentemente das propriedades das membranas, como a adesividade, crucial para aplicações de médicas em feridas. Nesse sentido, a proposta da pesquisa foi simular e avaliar a viscosidade de misturas poliméricas de quitosana de média massa molar (QM) e polivinilpirrolidona (PVP) em diferentes concentrações e proporções para síntese de membranas adesivas. Para tal, foi avaliado na literatura a viscosidade dos polímeros puros, simulado um modelo linear para viscosidade das misturas e, posteriormente, aplicado a metodologia de superfície de resposta (MSR) utilizando o modelo composto central, para três proporções QM/PVP em diferentes concentrações das soluções. A viscosidade dos polímeros QM e o PVP apresentam uma linha de tendência de crescimento exponencial, com baseado em dados da literatura, tendo um coeficiente de regressão satisfatório, e o modelo linear de simulação para viscosidade das misturas, demonstrou ser satisfatórios, considerando uma variação de 5%. Os gráficos de superfície resposta e contorno deixam evidentes o efeito da concentração da solução e proporção de mistura polimérica, e em quais situações de mistura é possível atingir níveis mais elevados e reduzidos da viscosidade. As informações obtidas na pesquisa são extremamente úteis, auxiliando no desenvolvimento das misturas poliméricas, de forma, a buscar as melhores condições, reduzir tempo de experimentos focando pontos de interesse.

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Substrate‐Independent, Reversible, and Easy‐Release Ionogel Adhesives with High Bonding Strength

Zhu

Lū

Zhang

et al. 2020

Macromol. Rapid Commun.

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structures to enhance the van der Waals interactions with the substrate. [5-7] Reversible and stimuli-responsive adhesives can also be fabricated based on stimuliresponsive polymers or polymer systems involving reversible and dynamic molecular interactions, such as the introduction of temperature or light isomerization groups, [8-10] dynamic covalent bonds [11,12] (e.g., Diels-Alder reaction, disulfide bonds) and reversible noncovalent interactions [13-20] (e.g., hydrogen bonds, metal-ligand and host-gust interactions). However, these adhesives were mostly reported to exhibit high-performance bonding with high-surface-energy substrates, such as glass and metal. The adhesion of inert low-surface-energy substrates, typically exampled by polytetrafluoretyhylene (PTFE), has been a long-standing challenge, because such substrates resist wetting and possess limited functional groups to form interfacial interactions with the adhesives. [21] Therefore, it is still highly desirable to develop substrate-independent, reversible and easyrelease temporal adhesives with high bonding strength. For the temporal adhesives that bond substrates based on their intrinsic viscoelastic properties, the bonding performance depends on both the adhesive and cohesive strength. [22-28] The adhesive strength is determined by the wetting ability of the adhesive and the interfacial interactions between the adhesive and substrates, whereas the cohesive strength depends on the mechanical rigidity of the adhesive. [26-28] Therefore, the adhesive with higher cohesive strength should be more solid-like with lower deformability, which, however, would prevent the wetting of the substrates by the adhesive and in turn may result in lower bonding performance. Conversely, the adhesives with higher adhesive strength should be more fluid-like with higher deformability, which would result in lower cohesive strength and thus may lower the bonding performance as well. Therefore, it is a big challenge to optimize the viscoelastic properties of a temporal adhesive to balance the adhesive and cohesive strength to maximize the bonding performance. Herein, taking advantages of the good wetting ability and nonvolatility of ionic liquids (IL), [29-31] ionogel adhesives are prepared by blending an imidazolium-based IL with a copolymer bearing charged quaternary amine groups. Homogeneous and stable ionogels can be obtained due to the electrostatic interactions between the charged moieties of the IL and the copolymer. The IL can promote the continuous contact between the

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Adhesives and Adhesion Technologies: A Critical Review

Cited by 4 publications

References 25 publications

Effects of Oxygen Plasma Treatments on Surface Functional Groups and Shear Strength of Carbon Fiber Composites

Effects of Oxygen Plasma Treatments on Surface Functional Groups and Shear Strength of Carbon Fiber Composites

Modelagem da viscosidade em mistura polivinilpirrolidona/quitosana para processamento de membrana adesiva

Substrate‐Independent, Reversible, and Easy‐Release Ionogel Adhesives with High Bonding Strength

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