4D Printing of Renewable Materials Derived from Glycerol and Maleic Anhydride with Tunable Thermal, Mechanical, and Fluorescent Properties

The demand for sustainable polymers in additive manufacturing has driven the search for renewable precursors capable of enabling advanced functionalities in 3D and 4D printing. In this work, renewable thermosets were developed from an α,β-unsaturated polyester derived from glycerol and maleic anhydride (PPH) combined with 2-hydroxyethyl methacrylate (HEMA), yielding photocurable resins with a theoretical biobased content of 97% and sustainable formulation scores above 43. The resins were processed via vat photopolymerization and subjected to a secondary UV postcuring step to induce tunable properties. The postcuring process increased monomer conversion, significantly enhancing thermal stability, maximum tensile strength, and hardness. Moreover, the materials exhibited luminescent behavior, attributed to polymerization-induced emission (PIE) and aggregation-induced emission (AIE) effects, marking the emergence of nonconjugated luminescent polymers. In addition, the PPH30-based polymer demonstrated high shape memory performance, with shape fixity and recovery ratios above 90% after multiple cycles, confirming its potential for 4D printing applications. Altogether, these findings highlight the feasibility of employing renewable feedstocks to design smart materials with tunable mechanical, thermal, and optical properties. This approach aligns with the sustainable development goals (SDGs), offering new pathways for greener manufacturing of advanced functional materials for engineering, biomedical, and optical applications.