Dimethyl Sulfoxide Separating Waste Printed Circuit Boards by Dissolving Polymer Materials

Abstract

AbstractThe separation of waste printed circuit boards (WPCB) has been a bottleneck in WPCB resource processing. In this study, the separation of WPCBs was performed using dimethyl sulfoxide (DMSO) as a solvent by dissolving polymer materials. Waste printed circuit boards of 1–1.5 cm2 in size were placed in DMSO at 60°C for 45 min. A metallographic microscope verified that the WPCBs produced the delamination. When the incubation time was increased from 45 to 210 min, polymer materials in WPCBs were dissolved by DMSO, and copper foils and glass fibers in WPCBs were separated completely. When the size of the WPCBs was increased from 1–1.5 to 2–3 cm2, the temperature of separating completely the copper foils and glass fibers in WPCBs increased from 60 to 90°C, but the separating time decreased from 210 to 90 min. The liquid photo solder resists (LPSR) were still adhered to the copper foils. The used DMSO was treated by rotary decompression evaporation, and the regenerated DMSO and solid residues were obtai...