Tuning the Functionality of Acrylated Vegetable Oil: Impact on the Physicochemical Properties of the 3D Printed Network

Abstract

Vat photopolymerization (VP) processing, an additive manufacturing (AM) technique, relies on the photopolymerization of light-sensitive resins. However, most commercially available resins are petrosourced and non-biodegradable. Recent reports have highlighted vegetable oils (VO) as promising bio-based alternatives, although their native carbon–carbon double bonds exhibit poor reactivity in free-radical polymerization. This limitation has been overcome by introducing polymerizable groups such as acrylates. Taking into account the growing interest in VO-derived resins, developing a deeper understanding of the influence of the acrylate functionality on the formulation behavior and the resulting 3D printed material performance is critical to enable a better control over their properties. In this work, canola oil (CO), a highly available feedstock in Canada, was acrylated to obtain resins with functionalities ranging from 1.87 to 2.78 average number of acrylate groups per molecule. The resulting formulations were characterized rheologically, photochemically, and mechanically. Our results show that increasing the average acrylate functionality per CO molecule leads to a lower critical energy (Ec) and penetration depth (Dp) in the context of the resin photopolymerization. Conversely, higher functionality improved the mechanical performance of the 3D printed samples, with tensile modulus increasing from 9 MPa to 18 MPa. This work deepens our understanding of how the degree of acrylation of CO influences the properties of 3D-printed materials, enabling the establishment of structure–processing-property relationships leading to a more rational design of these biobased photopolymerizable compounds.