Toward a Circular Economy: 3D Printing with Curable Vegetable Oil

Many of us have heard of using vegetable oil for alternative sources of energy like diesel gasoline, but you may be surprised to learn that it can play a role in 3D printing, too. Previous research has been performed in using vegetable oils with UV curing resins in SLA and DLP 3D printing; however, success has been limited. Authors Yanyan Cui, Junlai Yang, Dehua Lei, and Jiahui Su delve further into the study of alternative materials for 3D printing in the recently published “3D Printing of a Dual-Curing Resin with Cationic Curable Vegetable Oil.”

Dual-curing systems have been known to offer a high curing rate—along with better performance, such as improved mechanical properties and toughness. And, while many photopolymer 3D prints may be the result of dual-curing systems, in this study the researchers focus on the use of bio-based resins for stereolithography (SLA). They combine urethane-modified soybean oil with an epoxy group (urethane epoxidized soybean oil; SBOURE) to strengthen impact resistance of cycloaliphatic diepoxide, a binary monomer additive.

The advantages of using these materials and processes are:

• Simultaneous polymerization under exposure
• Fast curing rate
• Printed objects that are strong enough for creating interpenetrating network (IPN) structures, that is polymer connections that are interlaced but not covalently bonded.

Although cationic parts offer a low curing rate, the authors were able to overcome this with additional post-curing. With the inclusion of photoinitiated cationic SBO-URE, objects possessed the desired and sufficient strength—without decreasing elongation.

Initially, only mono-layer thickness spaces are present as the platform lowers to the bottom of the tank in this process, where the UV laser light is emitted for the curing of a thin layer on the platform. Afterward, the working platform rises and begins depositing layers. Ultimately, two IPNs were created, along with the IPN thermoset via SLA 3D printing.

Both hardness and gel content in the cured samples were “quite high,” connected with elevated cross-linking. Huge volume shrinkage was responsible for substantial stress internally, resulting in deformation; however, upon adding epoxidized vegetable oil, shrinkage was under control. A fullerene ball and a square pattern were 3D printed, both featuring ‘complex shape and fine structures.’ No cracks or delamination were present.

“Based on the above analysis, the addition of SBO-URE into the epoxy acrylate endowed the printed parts with excellent mechanical properties and high resolution, and this combination can potentially be used for renewable 3D printing materials,” concluded the researchers.

A variety of composite resins have been the focus of research studies in the past, to include the addition of graphene oxide elastomers, long carbon fibers, and thermoset composites for use in aerospace. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘3D Printing of a Dual-Curing Resin with Cationic Curable Vegetable Oil’]