Recycling Waste Circuit Board Efficiently and Environmentally Friendly through Small-Molecule Assisted Dissolution

Zhiqiang Chen,H Jerry Qi,Meng Yang,Xiao Kuang,Qian Shi,Tiejun Wang

doi:10.1038/s41598-019-54045-w

Zhiqiang Chen, H Jerry Qi + Show 4 more

Open Access

https://doi.org/10.1038/s41598-019-54045-w

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Abstract

With the increasing amount of electronic waste (e-waste) generated globally, it is an enormous challenge to recycle printed circuit boards (PCBs) efficiently and environmentally friendly. However, conventional recycling technologies have low efficiency and require tough treatment such as high temperature (>200 °C) and high pressure. In this paper, a small-molecule assisted approach based on dynamic reaction was proposed to dissolve thermosetting polymers containing ester groups and recycle electronic components from PCBs. This effective approach operates below 200 °C and the polymer could be dissolved in a short time. It has a remarkable ability to recycle a wide range of commercial PCBs, including boards made of typical anhydride epoxy or polyester substrate. Besides, it is environmentally friendly as even the recycling solution could be reused multiple times. In addition, the wasted solution after recycling could be used for board bonding and damage repair. This work also demonstrates the advantage of using polymers containing ester groups as the PCB substrate in consideration of eco-friendly and efficient recycling.

Highlights

Printed circuit boards (PCBs), the integral part of any electronic products, accounts for a great percentage of the total weight among those typical components dismantled from the e-waste
The solvent composed of ethylene glycol (EG), catalyst and organic solvent was used to dissolve the thermoset substrate containing ester groups in waste printed circuit boards (PCBs), and the electronic components could be separated from circuit boards
The degradation of organic materials is the key step in recycling waste PCBs

Summary

Introduction

Printed circuit boards (PCBs), the integral part of any electronic products, accounts for a great percentage of the total weight among those typical components dismantled from the e-waste. We attempted to use this small-molecule assisted method to recycle waste PCBs. The solvent composed of EG, catalyst and organic solvent was used to dissolve the thermoset substrate containing ester groups in waste PCBs, and the electronic components could be separated from circuit boards. Our work shows the small-molecule assisted method has a remarkable ability to recycle a wide range of commercial PCBs, including boards made of typical epoxy-anhydride and polyester resin substrate.

Results

Conclusion