Bio-based additive manufacturing materials: An in-depth structure-property relationship study of UV-curing polyesters from itaconic acid

UV-Curing Additive Manufacturing of Bio-Based Thermosets: Effect of Diluent Concentration on Printing and Material Properties of Itaconic Acid-Based Materials

“…In Figure , the DSC scans of the polyesters are shown. While similar resins in our previous work exhibited glass-transition temperatures in the range of <−50 °C up to 13.5 °C, this set of polymers had only a narrow range of the T g , with a maximum T g of −28 °C for PE-PhA. This exhibits the reduced influence of the secondary acid on the properties of the materials, as it is limited to 0.3 equiv of total acid used.…”

“…In addition, diluents can alter both the reactivity toward UV light and the final properties of the cured material. In our previous study, we were able to show that the structure of the polyester had a significant influence on the behavior of the formulation, as lower viscosities and flexible structures lead to higher conversions and better thermomechanical properties of the 3D-printed materials. However, it is also important to determine the influence of the amount of reactive diluent on the properties of the formulation and the subsequently fabricated materials.…”

“…Therefore, in order to be able to increase the overall bio-based content of AM materials two approaches can be followed: One possibility is the use of a combination of bio-based oligomers with bio-based diluents. Recently, we were able to show that the combination of itaconic acid-based polyesters with the bio-based diluent isobornylacrylate (IBOA) results in AM formulations with an overall bio-content of 85% . However, in this case, not all polyesters were able to form homogeneous formulations with this diluent and acryloyl morpholine (ACMO), a diluent from petrochemical resources, had to be used to be able to print these materials.…”

Itaconic Acid as a Comonomer in Betulin-Based Thermosets via Sequential and Bulk Preparation

“…Peaks at 1640, 940, and 813 cm −1 (Figure 2 and Figure S34) were present for both IA and the uncured MenMA monomer, which correspond to the stretching and deformation vibrations from the C�C bonds. 32,45 Comparing uncured resins to cured sequential thermosets, bands at 940 and 813 cm −1 disappeared after UV curing, indicating overall high conversion. Residual signals at 1640 cm −1 after curing could be due to residual unsaturations present; however, betulin exhibits a peak near 1640 cm −1 from the isopropenyl unsaturation.…”

“…Previously, we synthesized betulin-based polyester thermoplastics and thermosets with tunable high-performance properties using a series of linear aliphatic diacids . Recently, Papadopoulos et al reported the synthesis of thermoplastic polyesters from IA with varying linear aliphatic and aromatic diacid comonomers cured with acrylate reactive diluents for additive manufacturing (AM) materials . Shivarkar et al used IA to synthesize unsaturated polyesters that were then grafted with acrylic monomers to produce coatings with improved mechanical properties, adhesion, and weathering resistance .…”