Direct Ink Writing 3D Printing of Recyclable and Thermally Stable Vitrimers

Additive manufacturing (AM) strategies are extremely promising for their generality and flexibility, however they often produce materials with limited or degraded material properties. Vitrimers are polymers which exhibit self‐healing behavior that allows robust re‐work and recycling with minimal property loss, directly addressing this deficiency. Herein, a strategy is developed to additively‐manufacture copolyester vitrimers with gas‐generating cure reactions that are traditionally challenging to process. A composite gel is deposited as thin film using direct ink writing and cured via remote infrared heating, allowing evolved gases to diffuse and a stable film to form. Uniformly graded activated carbon particulate is added at a low volume fraction for infrared absorption and rheology tuning. The as‐manufactured material is compared to samples deposited via solvent spray and oven curing, using nanoindentation, nanoscratch, dynamic mechanical analysis, and thermogravimetric analysis. It is found to be well‐cured, maintaining its thermal stability and self‐healing capability. Its glass transition temperature and 5% mass loss threshold are above 200 °C and 350 °C respectively, and microscratches are fully repaired. These results demonstrate a viable fabrication technique for film deposition and freeform production of gas‐generating vitrimers, with direct applications in recycling and repair of wear resistant composites, thermal protection systems, and anti‐corrosion treatments.