The closing date for the inaugural FEICA / EURADH Adhesion Innovation Award has passed and the judges are now reviewing the entries. We received some outstanding entries for the Award that underline the huge potential for innovation in the adhesive and sealant industry.
A short summary of the submissions:
Dr André Arnebold
Network dynamics in cationically polymerised, crosslinked epoxy resins and its influence on crystallinity and toughness
Dr Arnebold’s work addresses a unique toughening concept for crosslinked epoxy resins and emphasises the ability of stress relaxation via network rearrangements, which is especially useful for adhesive bonds.
The resulting epoxy-based adhesive combines the advantages of thermoplastics and thermosets, which is novel in adhesion science.
Thermosetting plastics and adhesives serve as lightweight high-tech materials with outstanding properties but suffer from brittleness and nonrecyclability.
These two disadvantages are addressed by the adhesive described, which combines sustainability with cost reduction.
In addition, epoxy polyesters with dynamic crosslinks can be recycled via thermal reprocessing, which enables the reduction of plastic pollution of the environment, whereas thermosetting materials become damaging waste.
Dr Arnebold undertook the work for his Ph.D. at the University of Bremen, Bremen, Germany. He now works for adhesives manufacturer Wellmann Technologies GmbH, Friedelsheim, Germany.
Dr Marcelo Costa
Development of a cohesive zone model for adhesive joints that includes humidity and fatigue degradation
Dr Costa’s work encompasses the development of “JointDesigner”, a tool for the design of adhesive joints for various applications.
This facilitates the evaluation of the mechanical performance of structural adhesive joints.
Dr Costa has applied the concept to help solve adhesion related problems in collaboration with Honda R&D, John Deere, Nagase-Chemtex, Alstom and Sika.
In the case of the most recent collaborations with industry, the development of design methodologies for the fatigue behaviour of adhesive joints under mixedmode is being pursued with the end goal of replacing traditional joining techniques and reducing weight without sacrificing strength and security. This is leading to safe yet efficient vehicles, with lower fuel consumption and pollutant emissions.
Dr Costa did his Ph.D. in the Mechanical Engineering Faculty at the University of Porto, Portugal. He is currently a Post-Doc. Researcher at the Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Porto, Portugal.
Sensory characterisation and identification of odorous constituents in acrylic adhesives
Mr Denk’s research examined odorants in adhesives.
The main odorants in six different a crylic adhesives were investigated using state-of-the-art odorant analysis methods combined with human-sensory evaluation.
The most potent odorants were analysed by means of two-dimensional gas chromatography-olfactometry coupled with mass spectrometry (2D-GC-O/MS).
27 odorant were identified in the six samples, with 20 compounds that were reported for the first time as odorants in adhesives.
The formation pathway, chemical structure and the odour quality of the identified odourants are important in helping manufacturers develop strategies to produce low odour and emission adhesives and thus positively influence everyday odour exposure.
Philipp Denk received his degree in food chemistry at the University of Erlangen-Nuremberg, Nuremberg, Germany, in 2016. Mr Denk is currently doing a Ph.D., researching odours in adhesives on a molecular basis at the University of Erlangen-Nuremberg.
Dr René Hensel
Composite pillars with a tunable interface for adhesion to rough substrates
Inspired by nature, micropatterned dry adhesives are promising candidates for reversible, non-destructive adhesion, offering superior performance to non-patterned adhesives. Surface roughness induces a dramatic reduction in pull-off stresses and requires revised design concepts.
Dr Hensel introduced composite pillar structures to achieve adhesion to rough objects.
This provides a new solution for innovative pick-and-place technologies in industrial automation and robotics. In addition, composite structures can adhere to skin.
This can enable novel biomedical applications such as wound closures and self-adhesive transplants. Moreover, such skin adhesives would provide a new platform for applying wearable sensors, a research area that is still in its infancy.
Dr Hensel undertook his Ph.D. at the Max Bergmann Centre for Biomaterials at IPF -Leibniz Institute of Polymer Research, Dresden, Germany. Subsequently he joined INM – Leibniz Institute for New Materials, Saarbrücken, Germany, as a Post-Doc. to develop new bioinspired design concepts for micropatterned adhesive surfaces.
Dr Roman Pohrt
Strength of adhesive contacts: Influence of contact geometry and material gradients
Dr Pohrt investigated the influence of surface geometry on the adhesive detachment process of a flat and smooth contact zone fro m the mechanical point of view.
The two-dimensional shape of the contact zone was varied and a numerical analysis undertaken using a new formulation of the Boundary Element Method.
This work may help improve the mechanical properties and durability of bonded joints. The understanding of the shape dependence of adhesive contact also allows engineers to design bonds not only with regard to strength, but also with regard to a predictable failure. Applications could include earlywarning devices for mechanical load, predetermined breaking points or indicators for abuse in parcel delivery. In these cases, a cheap lightweight reusable adhesive joint can potentially replace more intricate single-use disposable products.
Dr Pohrt gained his Ph.D. at the Institute of Mechanics, Technical University of Berlin, Berlin, Germany, and is now a Post. Doc. at the same institution.
Dr Romana Santos
New sea urchin-inspired adhesives for biomedical applications: a biomimetic approach towards the development of new weteffective, reversible, biocompatible, and ecological adhesives
Dr Santos performed the first biochemical characterisation of the adhesive secretion of sea urchins, demonstrating that they produce both adhesive and de-adhesive secretions.
Currently, her research aims to develop new sea urchininspired, biocompatible and ecological adhesives, enabling the replacement of petrochemical-based adhesives by more sustainable, biocompatible, nature-inspired adhesives, especially in fields such as biomedicine, nanotechnology and tissue engineering.
Biomimetic sea urchin adhesives can find use as surgical adhesives or cell adhesion promoters for cell and tissue in vitro cultures.
In addition, the de-adhesive components may find biomedical application in reversible adhesives or as molecular displacers for the prevention of unwanted molecular or cellular adhesion to biomedical devices (e.g. heart valves and artificial blood vessels).
Dr Santos gained her Ph.D. in Biological Sciences at the University of Mons, Belgium, and is currently Principal researcher at the Marine and Environmental Sciences Centre (MARE), University of Lisbon, Portugal.
Dr Shoshan Abrahami
Cr (VI)-free anodising for adhesive bonding of aerospace aluminium alloys
Dr Abrahami studied the impact of parameters such as electrolyte type and the anodising conditions on the relationship between anodic aluminium oxide (AAO) properties and interfacial bonding.
Porous oxides were tested as environmentally responsible candidates to replace chromic acid anodising (CAA), because the REACH regulation will ban the commercial use of this process.
The work addresses a significant challenge facing aircraft manufacturers: the transition from a process relying on the toxic and carcinogenic Cr(VI) to more sustainable alternatives, while maintaining the high performance and safety demanded by the industry. Based on insights from this study and parallel industrial testing, Fokker Aerostructures is introducing a new Cr(VI)-free anodising line based on PSA (phosphoricsulphuric acid anodising) pretreatment in its processing plant.
Dr Abrahami did her Ph.D. at the Department of Materials Science and Engineering, Delft University of Technology, Delft, The Netherlands and the Materials innovation institute (M2i), Delft, The Netherlands. She is currently a Postdoctoral Fellow of the Research Foundation Flanders (FWO), Vrije Universiteit Brussel (VUB), Brussels, Belgium.
Markus Veltrup M. Sc.
Distribution and avoidance of debris on epoxy resin during UV ns-laser scanning processes for adhesive applications
Adhesive bonding of carbon fibre reinforced plastics (CFRPs), which are increasingly being used in transportation applications, requires pre-treatment of the surface to deliver high bond strength.
UV laser pre-treatment ablates the surface layer, removing contamination. However, the redeposition of ablated material (debris) on the treated surface can impair bond strength.
This work describes a laser scanning process with an adapted selection of pulse overlap with respect to laser fluence that reduces surface debris. As a result, laser pretreatment is effective and can eliminate labour-intensive manual grinding and the harmful solvents used in that process. This technique opens up new possibilities for adhesive technology in all areas of CFRP components, e.g. consumer goods, renewable energy, automotive and aviation industry.
Markus Veltrup M.Sc. is a Ph.D. student and research assistant at the Fraunhofer Institute for Manufacturing Technology and Applied Materials IFAM, Department of Plasma Technology and Surfaces (PLATO), Bremen, Germany.
Dr Andrés Jesús Yáñez-Pacios
Surface modification and improved adhesion of woodplastic composites (WPCs) made with different polymers by treatment with atmospheric pressure rotating plasma jet
Wood plastic composites (WPCs) offer an alternative to wood, but with the advantage of extremely high durability outdoors.
However, the use of WPCs is limited by their low adhesion. In addition, their traditional surface treatment of chromate in an acidic medium is not environmentally acceptable.
This work describes environmentally-friendly and sustainable surface treatment methodologies for WPCs that facilitate their decoration and adhesion.
Treatment with UV/ozone and atmospheric pressure rotating plasma jets (APPJ) produced notable chemical, morphological and physical modifications on the WPC surface which improved adhesion properties.
The treatments also facilitate innovative applications of WPCs that will allow the substitution of other materials in the construction and building industry. Furthermore, the formation of residues will be avoided and recycling will be promoted.
Dr Andrés Jesús Yáñez-Pacios did his Ph.D. in Materials Science at the University of Alicante, Alicante, Spain. He is currently an Associate Researcher at the University of Alicante’s Adhesion and Adhesives Laboratory.