Thermosetting polymers and composites present significant challenges for additive manufacturing due to the required speeds of printing in comparison to the time required for the curing reaction, relaxation of the printed ink, interfacial bonding of the printed layers, and integration of high aspect ratio fibers, among many other factors.  Our group recently developed a technique which combines direct ink writing with frontal polymerization (FP) of the thermosetting resin. Frontal polymerization is a curing process in which a thermal stimulus initiates a self-propagating reaction wave.   Our printing approach is based on the frontal ring-opening metathesis polymerization of <i>endo</i>-dicyclopentadiene (DCPD) using a thermally activated ruthenium catalyst. The DCPD ink is extruded from a print head onto a heated bed triggering the frontal polymerization (FP) reaction. Heat released from the polymerization activates adjacent monomer to further the curing process, thereby forming a self-sustaining propagating reaction wave that polymerizes the printed filament. The stiff polymerized segment of the filament can structurally support the printed part during its fabrication to produce three-dimensional (3D) free form prints with excellent fidelity. The resulting polydicyclopentadiene (pDCPD) is a cross-linked thermoset polymer with superior thermal and chemical stability. The fabricated parts exhibit a degree of cure of 99.2% and do not require further post-processing.  The addition of nanoparticles and other reinforcement phases allows access to a range of rheological profiles between low-viscosity liquid and free-standing elastomeric gel – all of which frontally polymerize upon thermal activation. This presentation will summarize the characterization of ink rheology for printing of composites, functionalization of the reinforcement/matrix interface, influence of printing parameters, and the resulting mechanical properties of the printed structures.<br/>

Direct ink writing of thermosetting composites using frontal polymerization

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.