Polyethylene furanoate (PEF) represents a promising renewable resource-based bioplastic as replacement for fossil-based polyethylene terephthalate (PET) with improved material properties. However, the synthesis of PEF through conventional polycondensation remains challenging, since the time-intensive reaction leads to degradation and undesired discolouration of the product. Here we show the successful rapid synthesis of bottle-grade PEF via ring-opening polymerisation (ROP) from cyclic PEF oligomers within minutes, thereby avoiding degradation and discolouration. The melting point of such mixture of cyclic oligomers lies around 370 °C, well above the degradation temperature of PEF (~329 °C). This challenge can be overcome, exploiting the self-plasticising effect of the forming polymer itself (which melts around 220 °C) by initiation in the presence of a high boiling, yet removable, and inert liquid plasticiser. This concept yields polymer grades required for bottle applications (Mn > 30 kg mol−1, conversion > 95%, colour-free products), and can be extended to other diffusion-limited polymer systems.

nature of polymer-based adhesives prevent their easy removal and stifle or complicate debonding, rebonding, (end-of-life) recycling, and repair. In this context, the development of debonding-on-demand (DoD) adhesive technologies is attracting rapidly growing interest. Indeed, DoD techniques have already entered commercial exploitation in applications such as easily removable wound dressings, [2,3] temporal fixation in semiconductor manufacturing, [4][5][6] and the repair, replacement, or recycling of components. [7][8][9] While many debonding technologies employ heat to reduce the adhesive strength by imparting physical property changes of the adhesive, [10][11][12][13][14] light-induced debonding technologies represent an emerging field and have been much less explored. Photoirradiation is an attractive alternative to thermal debonding as it allows an efficient, contactless, remote stimulation that can be temporally and spatially controlled. [15][16][17][18] Moreover, factors such as the irradiation wavelength, intensity, and time can easily be tuned and it is often possible to focus the energy entry to the adhesive and minimize or avoid exposure of (sensitive) substrates. Of course, the approach requires that at least one of the substrates to be bonded is sufficiently transparent.The design of a light-debondable adhesive system is strongly related to the adhesive type and the requirements imparted by the application(s) for which the adhesive is designed. For instance, pressure-sensitive adhesives (PSAs), such as used in adhesive tapes, need to efficiently adhere under ambient conditions with only a brief application of pressure, they should withstand the (comparably small) loads experienced while bonded, and they must also be easily removable, ideally without leaving any residues on the substrate. [19,20] PSAs are therefore normally based on lightly physically or chemically cross-linked rubbery polymers such as natural rubber, styrene butadiene block copolymers, and acrylics. These materials provide a balance between adhesive and cohesive performance, i.e., adequate stiffness and strength to resist deformation and cohesive failure, and appropriate elasticity in order to establish adequate contact with the substrate. [1] On the other hand, structural adhesives must be able to effectively transmit large loads across the bonded joint and the high strength and high rigidity required for this function are usually achieved by the formation of glassy networks. Examples of such materials include cross-linked epoxy resins, which may possess shear strengths of >35 MPa, cyanoacrylates (superglues), acrylics, and polyurethanes. [19] Adhesives that enable bonding and especially debonding on demand (DoD) have attracted rapidly growing interest in the last decade, as these capabilities greatly improve the functionality of adhesives, particularly in connection with temporal fixation, repair, and recycling. Indeed, DoD techniques have already entered commercial exploitation in applications such as easily removable wound dressin...