Tailoring Mechanical Properties for Additive Manufacturing: Strategic Molecular Design of UV-Curable Bio-based Oligoester Resins via Diacid and Diol Exploration

20 September 2024, Version 3
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Digital Light Processing (DLP) is a 3D printing technology that enables the fabrication of complex, high-resolution structures; however, the mechanical properties of DLP-printed objects are often limited by the resins used. This study focuses on developing and characterizing bio-based polyester UV-curable resins with tunable mechanical properties optimized for DLP 3D printing. Bio-based polyester resins were synthesized by direct esterification polycondensation reaction of itaconic and/or succinic acids with 1,2-propane-, 1,4-butane-, and/or 1,8-octanediols followed by blending with triethylene glycol dimethacrylate. The bio-renewable nature of the resin components provides several advantages over traditional petroleum-derived resins. The diacid and diol monomers come from renewable feedstocks such as corn, soybean, and vegetable oils rather than finite fossil fuel reserves. Furthermore, bio-renewable materials lower dependence on petrochemicals and increase the sustainability of 3D printing. The effects of diacid structure and diol chain length on resin properties were systematically investigated. Chemical characteristics were investigated by NMR and FTIR and suggested successful synthesis of the desired bio-based polyesters. By varying the molecular design, diacid, and diol building blocks, the molecular weight, crosslink density, and mechanical performance were tailored. The liquid resins were characterized by gel permeation chromatography and rheological measurements, and solid UV-cured objects were characterized by static and dynamic tensile testing. Rheological studies confirmed all resin formulations displayed shear-thinning behavior ideal for DLP printing. Mechanical testing revealed that varying diacid and diol components could modulate tensile elastic modulus and elongation at break from 0.1-1.0 GPa and 3.5-8.5%, respectively. Printability was assessed by printing a resolution test structure on a DLP 3D printer equipped with a 405 nm LED source. This ability to tailor the properties of bio-based polyester resins by molecular design provides an avenue for fabricating high-performance DLP-printed objects targeted for specific applications ranging from prototypes to end-use products.

Keywords

additive manufacturing
3D printing
UV-curable resins
mechanical properties

Supplementary materials

Title
Description
Actions
Title
Supporting Information for Tailoring Mechanical Properties for Additive Manufacturing: Strategic Molecular Design of UV-Curable Bio-based Oligomeric Polyester Resins via Diacid and Diol Exploration
Description
Supporting Information. Oligoester composition table, photographs of resins, tensile specimens, and 3D printed objects, FTIR and NMR spectra, GPC chromatograms, and rheological plots.
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.