Adhesives

2 pages, 149 KiB

Open AccessEditorial

by Vasileios Koutsos

Adhesives 2025, 1(1), 5; https://doi.org/10.3390/adhesives1010005 - 20 Mar 2025

Viewed by 282

Natural adhesives such as tree resins, gums, and tars have been used since prehistoric times (going back to at least 200,000 years [...] Full article

14 pages, 1727 KiB

Open AccessArticle

Investigating Multi-Material Additive Manufacturing for Disassembly and Reparability of Adhesive Joints by Precision Heating

by Mattia Frascio, Stefano Morchio, Francesco Musiari, Khalid Muhammad Usman, Federico Dittamo, Matilde Minuto and Massimiliano Avalle

Adhesives 2025, 1(1), 4; https://doi.org/10.3390/adhesives1010004 - 5 Feb 2025

Cited by 1 | Viewed by 790

Abstract

Additive manufacturing enables new design solutions across various engineering fields. This work presents a method to enhance the sustainability of adhesive joints by designing joints that can be disassembled and repaired multiple times. The approach involves the use of a Multi-Material Additive Manufacturing process to produce substrates with integrated circuits and electrical resistance, printed using a conductive filament. This resistance can be used to heat the thermoplastic adhesive layer up to 110 °C, allowing for reversibility in the assembly process and enabling joint re-use and repair without constraints on the component’s materials and thicknesses. The joints tested after successive assembly/disassembly operations reach maximum strength during the first iteration, which decreases by around 50% after five repair iterations. The focus of the work is on the feasibility of this process, but it is expected that performance can be improved after process optimization. This result could be highly valuable for enabling component in-service healing and the design for demanufacturing and remanufacturing. Full article

► Show Figures

Figure 1

10 pages, 646 KiB

Open AccessArticle

Influence of Quercetin and tt-Farnesol Enrichment on Physicochemical Properties of a Universal Adhesive System

by Roberta Janaína Soares Mendes, Regina Maria Puppin-Rontani and Aline Rogéria Freire de Castilho

Adhesives 2025, 1(1), 3; https://doi.org/10.3390/adhesives1010003 - 6 Jan 2025

Viewed by 653

Abstract

This study investigated the impact of natural compound enrichment, specifically quercetin and trans, trans-farnesol (tt-farnesol), on the physicochemical properties of a universal adhesive system. A preliminary DPPH assay was conducted to determine the optimal concentrations of quercetin (0.24 mg/mL) and tt-farnesol (1.43 mg/mL) based on their radical scavenging abilities. These compounds were then incorporated into the adhesive system. Specimens (n = 5; 7 mm × 1 mm) of the adhesive system, both with and without the added compounds, were prepared and tested for water sorption, solubility, Knoop hardness, and softening percentage. Water sorption and solubility were measured after immersion in deionized water for 7 days, and Knoop hardness was measured before and after immersion in 75% ethanol. Softening percentage was calculated based on changes in hardness. Data on water sorption, solubility, and percentage of softening were submitted to the Student’s t-test (α = 5%) while Knoop hardness values were submitted to the Mann–Whitney test (α = 5%). Both quercetin and tt-farnesol exhibited important antioxidant activity (85.5% and 82%, respectively). Water sorption was similar for both groups (p > 0.05) but the experimental adhesive had a significantly higher solubility, lower hardness, and higher softening. The incorporation of quercetin and tt-farnesol into a universal adhesive system detrimentally affects its essential physicochemical properties, compromising its performance. Full article

► Show Figures

Figure 1

12 pages, 2090 KiB

Open AccessArticle

Study of Non-Newtonian Fluids’ Load-Carrying Capacity for Polyoxyethylene Oxide Water-Based Lubricants

by Huaping Yao, Jimei Niu, Ruihua Zhang and Ping Huang

Adhesives 2025, 1(1), 2; https://doi.org/10.3390/adhesives1010002 - 24 Dec 2024

Viewed by 839

Abstract

Water-based lubricants have become increasingly prevalent across various fields due to their accessibility, cooling properties, and environmentally friendly characteristics. This study investigated the non-Newtonian properties of polyoxyethylene oxide (PEO) aqueous solutions. The rheological behaviors of 1%, 2%, and 3% PEO aqueous solutions were assessed using a flat plate rheometer. Shear strain responses were comprehensively analyzed, resulting in the derivation of the corresponding power law functions. The total loads of 1%, 2%, and 3% PEO aqueous solutions can be obtained by the numerical integration of Reynolds equations. Results indicate that at high shear strain rates, load-carrying capacity increased; however, the rate of increase gradually diminished as the shear strain rate rose. In practical applications, shear stress is subject to fluctuations; negative viscosity occurs resulting in reduced hydrodynamic pressure and potential lubrication failure. Full viscosity and incremental viscosity are introduced, with the latter being identified as a crucial factor that provides a more direct characterization of the relationship between shear stress and shear strain rate. This factor significantly influences the load-bearing capacity of the lubrication film in non-Newtonian fluids. Full article

► Show Figures

Figure 1

14 pages, 6655 KiB

Open AccessArticle

Dependence of the Molecular Interactions Between Cyanoacrylate and Native Copper Surfaces on the Process Atmosphere

by Philipp Moritz, Lienhard Wegewitz and Wolfgang Maus-Friedrichs

Adhesives 2025, 1(1), 1; https://doi.org/10.3390/adhesives1010001 - 24 Dec 2024

Viewed by 839

Abstract

Cyanoacrylates, known for their rapid polymerization and strong bonding capabilities, are widely used in industrial and medical applications. This study investigates the impacts of different process atmospheres with varying water and oxygen contents—air, argon, and argon/silane—on the curing and adhesion mechanisms of cyanoacrylate adhesives on oxidized copper substrates. Raman spectroscopy indicated that the curing process in argon and argon/silane atmospheres was slower compared to ambient air, likely due to the reduced moisture content of the atmosphere. However, the degree of curing and the inter- and intramolecular interactions within the adhesive volume showed no significant differences across atmospheres. X-ray photoelectron spectroscopy (XPS) and infrared reflection absorption spectroscopy (IRRAS) revealed that strong ionic interactions between cyanoacrylate and the copper surface oxide were absent in the low-moisture argon atmosphere. The introduction of silane resulted in the formation of silicon oxides and other silane-derived compounds, which probably contributed to the formation of these ionic interactions, similar to those observed in air. This study highlights the critical influence of the surrounding atmosphere on the adhesive properties of cyanoacrylates, with implications for optimizing bonding processes in various environments. Full article

► Show Figures

Figure 1

Journal Menu

Journal Browser

Adhesives, Volume 1, Issue 1 (March 2025) – 5 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI