title: Dissolution of brominated epoxy resins by dimethyl sulfoxide to separate waste printed circuit boards.
abstract: Improved methods are required for the recycling of waste printed circuit boards (WPCBs). In this study, WPCBs (1-1.5 cm(2)) were separated into their components using dimethyl sulfoxide (DMSO) at 60 °C for 45 min and a metallographic microscope was used to verify their delamination. An increased incubation time of 210 min yielded a complete separation of WPCBs into their components, and copper foils and glass fibers were obtained. The separation time decreased with increasing temperature. When the WPCB size was increased to 2-3 cm(2), the temperature required for complete separation increased to 90 °C. When the temperature was increased to 135 °C, liquid photo solder resists could be removed from the copper foil surfaces. The DMSO was regenerated by rotary decompression evaporation, and residues were obtained. Fourier transform infrared spectroscopy (FT-IR), thermal analysis, nuclear magnetic resonance, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to verify that these residues were brominated epoxy resins. From FT-IR analysis after the dissolution of brominated epoxy resins in DMSO it was deduced that hydrogen bonding may play an important role in the dissolution mechanism. This novel technology offers a method for separating valuable materials and preventing environmental pollution from WPCBs.
authors: Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China. xhnzp@shu.edu.cn
authors: Ping
authors: P
authors: Zhu
authors: Yan
authors: Y
authors: Chen
authors: Liangyou
authors: L
authors: Wang
authors: Guangren
authors: G
authors: Qian
authors: Wei Jie
authors: WJ
authors: Zhang
authors: Ming
authors: M
authors: Zhou
authors: Jin
authors: J
authors: Zhou
mesh_terms: D003300:Copper / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D004581:Electronics / Q000295:instrumentation; D004853:Epoxy Resins / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D054879:Halogenation; D059027:Recycling / Q000379:methods*; D012995:Solubility; D013696:Temperature
chemical_list: D004853:Epoxy Resins; C009753:fiberglass; D003300:Copper; D004121:Dimethyl Sulfoxide