Environmentally friendly plastics and biocomposites in additive manufacturing (3D printing)

Additive manufacturing, i.e. 3D printing, has revolutionized manufacturing processes by enabling the creation of complex geometries with minimal material waste. As global concerns about environmental sustainability grow, there has been increasing interest in developing and utilizing environmentally friendly materials that would reduce the use of conventional plastics. The adoption of environmentally friendly materials in additive manufacturing is growing, with approximately 40% of 3D printing users showing interest in sustainable materials. The adoption rate of biodegradable materials has increased by 15% over the past three years, and approximately 25% of 3D printed prototypes now use biodegradable materials. Applications for such materials can be found in medical industries, packaging, commodities, construction, automotive and aerospace industries. This lecture explores the current state, applications, advantages, limitations, and future possibilities of environmentally friendly plastics and bio-composites in additive manufacturing. There are two different approaches when discussing the environmental aspect of manufacturing. First one is recycling non-degradable materials and the other is creating materials that are fully or partially biodegradable (suitable for landfilling). The integration of recycled materials into 3D printing helps reduce environmental impact by decreasing the need for virgin raw materials, conserving natural resources, requiring less energy than production of virgin materials, and promoting circular economy. These materials are typically processed into filaments, pellets, or granules for use in the extrusion process. Mechanical properties are generally lower compared to virgin materials due to degradation of polymer chains during recycling. Biocomposites and bio-based plastics serve as environmentally friendly alternatives to conventional petroleum-based plastics. These materials offer significant environmental benefits through biodegradability and/or derivation from renewable resources, reduced carbon footprint at the resource extraction stage, and contribution to a sustainable economy. Three main categories of bioplastics are distinguished: biodegradable bioplastics made from bio-based materials, bio-based but nonbiodegradable plastics, and biodegradable plastics made from fossil-based resources. Natural Fiber-Reinforced Composites (NFRCs), also known as "green composites," enhance the mechanical properties of the material and have a lower environmental impact than traditional composites. Agricultural residues are promising feedstock materials in additive manufacturing, providing a cheaper alternative, utilizing waste materials, and improving the sustainability of the manufacturing process.