Development and Evaluation of 3D Printing Filament from Mixed Plastic Waste: An Alternative Recycling Strategy
Faculty Mentor Information
Armando McDonald, University of Idaho
Presentation Date
7-2025
Abstract
The accumulation of mixed plastic waste (MPW), largely composed of polypropylene (PP) and polyethylene (PE), presents a growing environmental challenge due to rising demand and the absence of economically viable recycling methods. This project explored the feasibility of repurposing MPW into 3D printing filament through custom extrusion and printing techniques, with adjustments to extrusion and print settings such as temperature, speed, and bed adhesion techniques to optimize filament quality and printability.
Initial mechanical testing showed that MPW-based filaments perform similar to pure PP filaments, with tensile strengths of 16.1 MPa (MPW) and 16.9 MPa (PP), and Young’s modulus of 823 MPa and 1001 MPa, respectively. Additionally, flow and elasticity were evaluated using rheometry, while thermal properties were assessed through calorimetry. Overall, MWP and PP filaments are flexible and have low strength compared to commonly used polylactic acid (PLA) filaments. Our findings suggest that MPW filaments could serve as a replacement for PP in many applications, and as a limited substitute for PLA where high strength is not required. By transforming waste destined for landfill into reusable material, our project promotes a circular economy and supports sustainable manufacturing practices.
Development and Evaluation of 3D Printing Filament from Mixed Plastic Waste: An Alternative Recycling Strategy
The accumulation of mixed plastic waste (MPW), largely composed of polypropylene (PP) and polyethylene (PE), presents a growing environmental challenge due to rising demand and the absence of economically viable recycling methods. This project explored the feasibility of repurposing MPW into 3D printing filament through custom extrusion and printing techniques, with adjustments to extrusion and print settings such as temperature, speed, and bed adhesion techniques to optimize filament quality and printability.
Initial mechanical testing showed that MPW-based filaments perform similar to pure PP filaments, with tensile strengths of 16.1 MPa (MPW) and 16.9 MPa (PP), and Young’s modulus of 823 MPa and 1001 MPa, respectively. Additionally, flow and elasticity were evaluated using rheometry, while thermal properties were assessed through calorimetry. Overall, MWP and PP filaments are flexible and have low strength compared to commonly used polylactic acid (PLA) filaments. Our findings suggest that MPW filaments could serve as a replacement for PP in many applications, and as a limited substitute for PLA where high strength is not required. By transforming waste destined for landfill into reusable material, our project promotes a circular economy and supports sustainable manufacturing practices.