Debondable adhesives and their use in recycling

Abstract

Structural adhesives are commonly used to join dissimilar materials and are of particular interest in complex technological devices used in automotive, telecommunications, photonic devices, aerospace and sustainable power production and...

Photoswitchable Adhesives of Spiropyran Polymers

“…4−8 In this context, switching of adhesives between strong bonding during use and on-demand debonding by external stimuli is a key technology to achieve both development of complex architectures and material recycling. 9,10 In particular, light is an ideal stimulus that can minimize effects on adherends due to the high spatiotemporal resolution and easy, precise control of the intensity and wavelength. 11 To date, photoswitchable adhesives have been developed by utilizing a variety of photoresponsive systems including large structural changes of azobenzenes, 12−28 conjugation changes of diarylethenes, 29,30 dimerization of anthracenes, 31−34 photothermal effects of supramolecular motifs and dyes, 35−39 and other reactions.…”

“…Complex architectures consisting of organic, inorganic, and metallic components are being developed in various fields such as vehicles and electronics to maximize the benefits of each material. , For joining the dissimilar materials, the use of adhesives is a dominant method including combination uses with other methods, e.g., mechanical fastening, due to the advantages such as stress distribution, weight saving, design flexibility, mild joining conditions, and applicability to a wide range of materials. Meanwhile, as represented by marine plastic pollution, global environmental problems are worsening, and material recycling is strongly required. − In this context, switching of adhesives between strong bonding during use and on-demand debonding by external stimuli is a key technology to achieve both development of complex architectures and material recycling. , In particular, light is an ideal stimulus that can minimize effects on adherends due to the high spatiotemporal resolution and easy, precise control of the intensity and wavelength . To date, photoswitchable adhesives have been developed by utilizing a variety of photoresponsive systems including large structural changes of azobenzenes, − conjugation changes of diarylethenes, , dimerization of anthracenes, − photothermal effects of supramolecular motifs and dyes, − and other reactions. − Reversibly switchable polymer adhesives are particularly attractive because of their strong adhesion and recyclability.…”

The sustainable materials roadmap

“…This frustrates recycling and disassembly. Development of 'reversible adhesives' [330] or even substituting adhesives with other joining methods could significantly enable disassembly and recovery of active materials [328]. Designing complex technology products for disassembly will facilitate a greater shift towards a circular economy [328].…”

Switchable Adhesion: On‐Demand Bonding and Debonding

“…Reversible adhesives can be reused several times rather than becoming useless after curing, which is environmentally friendly and economical. [22] Recently, Ko et al reviewed switchable actuators and adhesives for the reconfigurable matter. [23] They focused on material and device structure designs to shorten the response time, enhance the reversibility, multistimuli responsiveness, and smart adhesion for efficient shape transformation and functional actuations.…”

“…Reversible adhesives can be reused several times rather than becoming useless after curing, which is environmentally friendly and economical. [ 22 ]…”