Conversion of printed circuit board polymer into graphitic materials during laser-induced carbonization process
Date
2025-05
Authors
Islam, Md Kaviul
Major Professor
Advisor
Shrotriya, Pranav
Nlebedim, Cajetan I
Mba-Wright, Mark
Secor, Ethan
Lee, John
Committee Member
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Abstract
The increasing generation of electronic waste (e-waste) poses significant challenges to global environmental sustainability and public health. Driven by rapid technological advancements and growing consumption of electronic devices, e-waste has become a critical concern due to its complex composition, particularly in printed circuit boards (PCBs). While significant progress has been made in recovering precious metals such as gold, copper, and palladium through established recycling methods like hydrometallurgical and pyrometallurgical processes, the non-metallic components—comprising fiberglass and epoxy resins—are often discarded or incinerated, contributing to environmental pollution. Addressing these challenges requires innovative recycling approaches that effectively utilize both metallic and non-metallic fractions.
This study introduces a novel method for PCB recycling by employing ultrashort pulse picosecond laser treatment to carbonize the epoxy polymer matrix into graphitic materials under ambient conditions. Pre-treatment characterization using techniques such as TGA-MS-FTIR and XRF provided valuable insights into thermal stability, gas evolution, functional groups, and elemental composition. Parametric optimization of the laser treatment process, varying power, speed, and line energy demonstrated successful graphitization of the polymer matrix. Post-treatment analyses, including Raman spectroscopy, SEM, and EDS, revealed reduced sheet resistance and enhanced conductivity. Higher line energy conditions resulted in lower sheet resistance but exhibited a higher defect density in the graphitic structure. Conversely, double treatments under lower line energy achieved optimal graphitization, with fewer defects and evidence of few-layer graphene-like structures. Excessive treatments, however, caused structural degradation due to thermal stress. This work provides an innovative recycling strategy for non-metallic PCB fractions, aligning with sustainable resource recovery practices and circular economy objectives while addressing the escalating e-waste crisis.
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Mechanical Engineering
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article