Dimethyl sulfoxide separating waste printed circuit boards by dissolving polymer materials

The 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 in size were placed in DMSO at 60 degrees C for 45min. A metallographic microscope verified that the WPCBs produced the delamination. When the incubation time was increased from 45 to 210min, 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 , the temperature of separating completely the copper foils and glass fibers in WPCBs increased from 60 to 90 degrees C, but the separating time decreased from 210 to 90min. 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 obtained. This new technology offers a new way to separate valuable materials from WPCBs.