Fabrication and Mechanical Properties of High-Durability Polypropylene Composites via Reutilization of SiO2 In-Situ-Synthesized Waste Printed Circuit Board Powder.

Shenghui Tian,Xinlu Liu,Baixue Li,Zuolu Zhang,Xin Wen,Hui He

doi:10.3390/polym14051045

Abstract

This paper focuses on the characterization of the physico-chemical properties, surface modification, residual copper content and in situ hybrid inorganic particle modification of polypropylene (PP) composites reinforced by waste printed circuit board powder (WPCBP). A series of WPCBP/SiO2 hybrids (TSW) were prepared by a sol–gel method at different pH values. Characterization results revealed the in situ generation of SiO2 on the surface of WPCBP, and showed that with an increase in pH value, the size of SiO2 particles increased gradually and the copper content decreased in the TSW powder. The mechanical properties, oxidation induction time (OIT) and thermal properties of PP composites were improved by reinforcement with TSW, which might be ascribed to the formation of serrated interfaces. This work not only develops a powerful method to enhance the properties of PP/WPCBP composites, but also provides an environmentally sustainable approach to the high-added-value reutilization of WPCBP.

Highlights

Ammonia was used as an alkali shrinkage agent to synthesize SiO2 in situ on the surface of waste printed circuit board powder (WPCBP) by the Tetraethyl orthosilicate (TEOS) method (Figure 1)
A series of TSW powders were prepared with different pH values
We studied the effects of TSW hybrids generated under various pH values on the mechanical properties of PP composites

Summary

Introduction

According to United Nations estimations, the global output rate of e-waste has been growing by 10% every year and the total production of e-waste has reached more than 50 million tons annually [1,2]. An effective method to resolve the increasingly serious environmental pollution problems is to realize the recycling and reuse of these e-wastes. The metal in waste printed circuit boards (WPCBs) is easy to recycle and reuse, providing high economic benefits which have been effectively realized in industry [5,6], whereas the non-metallic portions of WPCBs are difficult to effectively reutilize owing to their complex composition, and are consigned to landfill or combustion [7]. It is important to achieve the high-value recycling of WPCBP. The intrinsic complexity of WPCBP components makes their recovery very difficult, and their economic value is low [10,11]. The short glass fibers contained in WPCBP could be used as filler to improve the properties of a polymer matrix, providing a new alternative for recycling and reusing WPCBP while reducing production costs [12,13]. The chemical structures of WPCBP and WPCBP-reinforced polymer composites exhibit poor interfacial properties, narrowing the scope of their application in certain fields

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Conclusion