Dynamic covalent polymer networks (DCPNs) combine intrinsic reversibility with the robustness of covalent bonds, creating polymers whose crosslinking network can dissociate when exposed to certain external stimuli. Herein, we report a versatile approach to designing 3D printable and re-processable DCPNs with controllable mechanical properties. The approach involves synthesis of epoxy-based oligomeric building blocks of controllable length which are then reversibly crosslinked within covalent networks. The reversibility was enabled by Diels-Alder (DA) reaction between furan moieties of the epoxy-based oligomeric precursor and maleimide moieties of a crosslinker agent. The “click” characteristic of DA reactions enabled fast curing of the DCPNs, which reversibly dissociated at elevated temperatures via retro DA reaction. The low viscosity of dissociated networks (several Pa*s at 130 oC) facilitated 3D printing of the materials via fused deposition modeling. Importantly, the DA reactivity of the precursor material improved interlayer adhesion during printing. Using this approach, the same oligomeric precursor could be used with variable amounts of crosslinker for the fabrication of a series of DCPNs with the glass transition temperatures precisely controlled between -10 and 35 oC. The DCPNs demonstrated programmable MPa-range elastic moduli, and fast self-healing behavior. Moreover, the shape of printed DCPN materials could be re-programmed via isomerization between two DA adducts. These results suggest a new and promising pathway into the development of versatile materials for additive manufacturing of multifunctional adaptable structures.

Printable, re-processable dynamic covalent polymer networks via Diels-Alder “click chemistry”

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.