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Abdollahi Goraghani, Nadia

University of British Columbia

Polyethylene terephthalate glycol-modified (PET-G) is widely used in packaging, medical products, and 3D printing due to its enhanced flexibility, clarity, and chemical resistance. However, its modified chemical structure makes PET-G incompatible with standard polyethylene terephthalate (PET) recycling processes, leading to considerable environmental challenges as PET-G waste often ends up in landfills or incinerated. As an alternative, this study explores the mechanical recycling of PET-G by incorporating carbon nanotubes (CNT) to develop high-performance nanocomposites suitable for electromagnetic interference (EMI) shielding applications. Three grades of PET-G, two recycled and one virgin, were processed using twin-screw extrusion to integrate CNT at five different weight concentrations (1–5 wt%). Compression molding was then employed to prepare test specimens for comprehensive morphological, mechanical, electrical, thermal, and EMI shielding characterization. The incorporation of CNT enhanced the mechanical properties of the recycled PET-G nanocomposites, with a notable increase in elastic modulus and improvement in tensile strength compared to the base recycled PET-G. Electrical conductivity measurements revealed a percolation threshold at around 3 wt% CNT, beyond which conductivity increased markedly due to the formation of conductive networks which is an essential feature for effective EMI shielding. The nanocomposites exhibited substantial EMI shielding effectiveness at CNT concentrations above 4 wt%, indicating their suitability for applications in electronics, automotive components, and aerospace devices. To balance material performance and processing efficiency, a multi-criteria decision-making (MCDM) framework, specifically the PROMETHEE II method, was utilized. This approach guided the selection of the optimal CNT loading and the neat polymer for potential target applications (e.g. EMI in electronic devices), while evaluating multiple decision criteria concurrently. In conclusion, this research demonstrates that recycling PET-G waste into CNT-reinforced nanocomposites can present a viable and sustainable pathway for further reducing plastic waste while creating high-value materials for advanced technological applications. By transforming PET-G waste into functional new materials suitable for EMI shielding, the study contributes to circular economy practices and reduces reliance on virgin plastics.

Text

2024-12-20

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/89962

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/