Abstract

Improper handling of waste printed circuit boards (PCBs) can cause serious pollution to the water and soil environments. In order to explore a new method of recycling waste PCBs, this study investigated the effect of PCBs and butadiene styrene rubber (SBR) on the rheological properties of neat bitumen. The dynamic shear rheological (DSR) test was used to study the effect of different PCB contents on the high-temperature rheological properties of SBR-modified bitumen. Fluorescence microscopy and Fourier-transform infrared spectroscopy were used to study the microstructure change law and modification mechanism of PCB and SBR composite modified bitumen. Finally, the feasibility of the bitumen properties was verified through a test of the bituminous mixture properties. The DSR test results showed that the addition of PCBs improves the elastic recovery modulus, dynamic shear modulus, and rutting factor of SBR-modified bitumen, indicating that the high-temperature properties were improved. Infrared spectroscopy analysis revealed that a new absorption peak was generated in the infrared spectrum of the compound bitumen after the addition of PCBs, and the intensity of the original absorption peak also changed, indicating that PCBs and SBR-modified bitumen were mainly physically blended and accompanied by a weak chemical reaction. It was further found that the absorption peak of the unsaturated C=C double bond was significantly enhanced, and the increase in the content of the unsaturated bond C=C in the main chain of the polymer significantly increases the stiffness of the bitumen. Macroscopically, the high-temperature rutting resistance was improved to a certain extent. The fluorescence diagram shows that when PCBs do not exceed 10%, the PCBs can form a homogeneous structure and be dispersed in SBR-modified bitumen. The road test of PCBs and SBR composite modified bituminous mixtures showed that PCBs can significantly improve the rutting resistance and water stability of SBR-modified bitumen at high temperatures at the recommended optimum content. The crack resistance at low temperatures is weakened but still meets actual engineering requirements. The correlation analysis between the properties of bitumen and bituminous mixtures is carried out based on grey correlation theory. The results show that the index of modified bitumen has a very good guiding effect on the bituminous mixture properties. The development of PCBs and SBR composite-modified bitumen provides a new practical method for recycling waste PCBs.

Highlights

  • The worldwide demand for electronic products is constantly increasing, included in which is the rapid growth of the production of printed circuit boards (PCBs) [1]

  • Based on grey relational theory, this study investigated the macro and micro performance indexes of bitumen to evaluate the reliability of bituminous mixture properties

  • This study aimed to study the influence of PCBs on the rheological properties of SBRmodified bitumen and solve the problem of environmental pollution caused by improper treatment of waste PCBs

Read more

Summary

Introduction

The worldwide demand for electronic products is constantly increasing, included in which is the rapid growth of the production of printed circuit boards (PCBs) [1]. The proportion of waste PCBs in e-waste is approximately 3%, and the average annual growth rate is 17–25%, which is one of the highest among all types of e-waste. The metal components are mainly copper, gold, silver, lead, and tin, accounting for approximately 30% of the PCB plate. Disposal in landfill causes heavy metal elements such as bromine, lead, and mercury in the PCB boards to infiltrate into the ground, causing irreversible pollution of the soil and groundwater [5,6,7,8]. It can be seen that the disposal of waste PCBs by incineration or landfill both wastes resources and seriously pollutes the environment. There is an urgent need to develop new technologies to solve the current waste PCB disposal problem [9]

Objectives
Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call