Frontal Polymerization Assisted Printing of Biobased Epoxy Composites

Frontal polymerization, when applied to additive manufacturing, substantially reduces energy consumption and enhances printing efficiency. Additionally, this technology facilitates the fabrication of free-standing structures, eliminating the need for support structures. However, most resins utilized for frontal polymerization are predominantly derived from petroleum feedstocks. In this research, an innovative resin was developed using a bio-derived epoxy composed of sorbitol polyglycidyl ether (SPGE) and methyl cellulose (MC), cured with m-xylylenediamine (m-XDA) and 4-dimethylaminopyridine (DMAP). The formulation was optimized to enhance reactivity and rheological behavior, facilitating the printing of intricate, self-supporting structures. The addition of MC notably increased the resin’s viscosity at elevated temperatures, thus improving the stability during printing. Increasing the proportion of DMAP was found to raise the frontal temperature and speed of the polymerization front, corroborated by differential scanning calorimetry (DSC) results. Optimal results were achieved with a resin composition containing 5 wt% MC and 4 wt% DMAP, demonstrating suitability for frontal printing applications. Mechanical testing of both molded and frontally printed specimens indicated that the specimens produced through frontal polymerization assisted printing possessed comparable tensile strength (45MPa) and flexural strength (65MPa). The capability to print diverse geometries using a desktop 3D printer was successfully demonstrated, marking a significant advancement in the field of additive manufacturing with the potential for increased use of bio-derived materials.