(Meth)acrylate-Free Three-Dimensional Printing of Bio-Derived Photocurable Resins with Terpene- and Itaconic Acid-Derived Poly(ester-thioether)s

Vat photopolymerization, a very efficient and precise object manufacturing technique, still strongly relies on the use of acrylate- and methacrylate-based formulations because of their low cost and high reactivity. However, the environmental impact of using fossil fuel-based, volatile, and toxic (meth)­acrylic acid derivatives is driving the scientific community toward the development of alternatives that can match the mechanical performance and three-dimensional (3D) printing processability of traditional photocurable mixtures but are made from environmentally friendly building blocks. Herein, itaconic acid is polymerized with polyols derived from naturally occurring terpenes to produce photocurable poly­(ester-thioether)­s. The formulation of such polymers using itaconic acid-based reactive diluents allows the preparation of a series of (meth)­acrylate-free photocurable resins, which can be 3D printed into solid objects. Extensive analysis has been conducted on the properties of photocured polymers including their thermal, thermomechanical, and mechanical characteristics. The findings suggest that these materials exhibit properties comparable to those of traditional alternatives that are created using harmful and toxic blends. Notably, the photocured polymers are composed of biobased constituents ranging from 75 to 90 wt %, which is among the highest values ever recorded for vat photopolymerization applications.