A Green Chemistry Approach to Designing Bio-based Resins for 3D Printing

Sustainability has become a great topic of interest in recent years. Most associate sustainability with how a material is produced, consumed, and disposed of, and how this continuous cycle effects the environment. However, sustainability is a much more complex concept with nuance regarding its reach on societal issues such as resource inequality and access, as well as, economic availability and convenience. The reliance on petroleum-based materials, such as plastics, in modern day society has been discussed in great depth in relation to sustainability. This is due to fossil fuels being main contributors to environmental pollution, resource degradation, and rising global temperatures. On the other hand, the dependence on plastics in almost every industry is a result of their ease of production, favorable mechanical properties, and cost effectiveness. Because of this, it will be difficult to influence a shift from petroleum-based materials to more bio-based materials if these new materials do not perform similarity to industrially used plastics. It is also crucial to consider the manufacturing processed used to produce the materials. Competitive manufacturing techniques such as 3DP (3D printing) has become a desired technique due to its ability to fabricate complex, uniform, and flexible products without the use of molds or machining, its ability to provide fast, on-site production, and its cost-effective nature without wasting unnecessary materials or excessive waste production. The main goal of this research was to develop bio-based resins that are compatible with digital light processing 3D printing technologies (DLP 3DP) and optimize these materials such that they have comparable properties to commonly utilized plastics. Not only that, but a focus on designing materials that can be chemically recycled, thermally healed, and mechanically reprocessed while maintaining their mechanical properties, will help to produce a movement toward the implementation of more eco-friendly materials. Here, a background on the sustainability movement and its evolution, as well as, the issues associated with plastics will be discussed. Additionally, the implementation of bio-based feedstocks within the design of recyclable, self-healable, and reprocessable thermosets will be investigated and looked at through a green chemistry lens. The concepts explaining the various 3DP technologies, the pros of utilizing such techniques, and the fabrication of 3D printable resins will be explored. Finally, applications of such concepts utilizing bio-based feedstocks such as functionalized vanillin, guaiacol, and eugenol with scientific, peer-reviewed research with the reported findings will be presented.