Honors Theses


Robert Lowe


Mechanical and Aerospace Engineering

Publication Date


Document Type

Honors Thesis


Consumer grade additive manufacturing, colloquially referred to as 3D printing, has become a popular means of rapid prototyping and fabrication used by engineers, educators, artists, and hobbyists alike. As companies begin to produce recycled filament as feedstock for fused filament fabrication (FFF) 3D printers, it is important to quantify differences in the mechanical properties of virgin and first-reuse recycled plastics so that users can determine the viability of recycled filament for various end-use applications. This thesis explores the mechanical properties of two common postconsumer thermoplastics, rPLA and rPETG (where rPLA/rPETG denotes 100% recycled PLA/PETG), in comparison to their virgin counterparts to determine viability for use in consumer grade additive manufacturing. Results from mechanical testing indicated no statistically significant differences in modulus of elasticity, ultimate tensile strength (UTS), and percent elongation at UTS between PETG and rPETG, as well as no statistically significant difference between PLA and rPLA’s modulus of elasticity and percent elongation at UTS. Although rPLA showed a statistically significant increase in UTS compared to its virgin counterpart, this difference is likely mechanically insignificant for most practical engineering applications. Thus, the argument can be made for a wider use of recycled plastic in consumer additive applications, resulting in less waste generation, lower carbon emissions, and even potential cost savings without compromising the mechanical properties of PLA or PETG.

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This item is protected by copyright law (Title 17, U.S. Code) and may only be used for noncommercial, educational, and scholarly purposes.


Undergraduate research