Dear Colleagues,

Introduction: Over the past decade, a new class of polymers (i.e., vitrimers) has received a great deal of attention in both academia and industry. Vitrimers possess high strength and high modulus, similar to thermoset polymers, while being recyclable and reprocessable, similar to thermoplastic polymers [1]. This is due to the dynamic covalent chemistry in the backbone of polymer structures. Moreover, vitrimers can be fully recycled, reprocessed in a closed loop [2], and weldable and strong as virgin polymer [3]. Additionally, carbon fibers might be reclaimed from the polymer structure non-destructively [4]. Moreover, the properties of these vitrimers might be finely tuned by changing their crosslink density [5]. Despite having some basic knowledge of this class of polymers, most of the phenomenon in detail is still worth exploring. Changing a new dynamic bond might entirely change the recycling behavior and properties of the polymer. Thus, this Special Issue aims to welcome those new findings in this research direction.

Challenges: Though several research works have been made, it is still challenging to overcome many problems, such as:

• Retaining high modulus and full recyclability;
• Easy, one-step, catalyst-free synthesis;
• Fully biobased vitrimers from renewable feedstock;
• Nontoxicity of vitrimers;
• Fast dynamics under certain stimuli;
• Easy reclamation of fibers and fillers from composites, etc.

Thus, this Special Issue invites authors to address these new and innovative topics to fill the research gap.

Aim of the special issue: This Special Issue welcomes experts working in vitrimer synthesis and processing, self-healing polymers, dynamic covalent chemistry, reversible reactions, sustainable chemistry, and simulations for vitrimers. These innovations might be in monomers, polymers, thermosets, composites, and other applications. All kinds of interrelated innovations in the polymers, chemistry, and composite industry related to vitrimers are warmly welcomed.

References

1. Memon, H.; Wei, Y.; Zhu, C. Recyclable and reformable epoxy resins based on dynamic covalent bonds – Present, past, and future. Polym. Test 2022, 105, 107420, doi:https://0-doi-org.brum.beds.ac.uk/10.1016/j.polymertesting.2021.107420.
2. Memon, H.; Liu, H.; Rashid, M.A.; Chen, L.; Jiang, Q.; Zhang, L.; Wei, Y.; Liu, W.; Qiu, Y. Vanillin-Based Epoxy Vitrimer with High Performance and Closed-Loop Recyclability. Macromolecules 2020, 53, 621-630, doi:10.1021/acs.macromol.9b02006.
3. Memon, H.; Wei, Y. Welding and reprocessing of disulfide-containing thermoset epoxy resin exhibiting behavior reminiscent of a thermoplastic. Journal of Applied Polymer Science 2020, 137, 49541, doi:https://0-doi-org.brum.beds.ac.uk/10.1002/app.49541.
4. Memon, H.; Wei, Y.; Zhang, L.; Jiang, Q.; Liu, W. An imine-containing epoxy vitrimer with versatile recyclability and its application in fully recyclable carbon fiber reinforced composites. Compos. Sci. Technol. 2020, 199, 108314, doi:https://0-doi-org.brum.beds.ac.uk/10.1016/j.compscitech.2020.108314.
5. Memon, H.; Wei, Y.; Zhu, C. Correlating the thermomechanical properties of a novel bio-based epoxy vitrimer with its crosslink density. Materials Today Communications 2021, 29, 102814, doi:https://0-doi-org.brum.beds.ac.uk/10.1016/j.mtcomm.2021.102814.

Dr. Hafeezullah Memon
Prof. Dr. Steven Nutt
Prof. Dr. Yi Wei
Guest Editors

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• synthesis of vitrimers
• epoxy vitrimers
• self-healing
• dynamic covalent chemistry
• reversible reactions
• 3D printing
• vitrimer processing
• sustainable chemistry
• biobased polymers
• crosslink density
• simulations for vitrimers
• vitrimer composites