Additive manufacturing of recycled plastics for sustainable STEM education

Polymer waste is an increasing environmental challenge, and education on this issue can lead teachers and students to play a role in protecting the environment. Recycled plastics in 3D printing (3DP), also known as additive manufacturing (AM), offer new possibilities in managing material waste, aligning with sustainability and circular economy principles. This paper presents the current state of the art regarding plastic waste management and recycling processes, focusing on the use of recycled plastic materials in AM technology. The review emphasizes that AM using recycled plastics can improve the learning environment in science, technology, engineering, and mathematics (STEM) education. AM can be used as a reuse model to encourage sustainability-oriented creativity in students by incorporating environmental awareness along with technical training. This study also presents a STEM-based case study in which waste PET bottles were converted into feedstock filaments and extruded into porous cups using material extrusion (MEX) AM. The cups were utilized in a hydroponic system to grow mint plants, allowing students to gain hands-on experience in materials, design, and sustainable farming. The system demonstrated sufficient strength to prevent water leakage, underscoring the importance of incorporating circular-economy principles into STEM education. This review also offers a framework to enhance the existing relationship between digital manufacturing and learning by adopting a multi-disciplinary approach to this complex global challenge.