1133984 (Zhang). Widespread use of electronic equipment and shortening of product life cycles have created the challenging task of dealing with the ever-increasing quantity of obsolete electronic equipment. The huge amount of electronic waste (E-waste) generated each year and the lack of established methodologies capable of handling the increasing volumes of E-waste pose a severe environmental threat. Among the challenges to successful electronic equipment recycling, printed circuit board (PCB, primary components in every type of electronic product) recycling is recognized as one of the most difficult problems because of the complex construction and complicated materials composition of PCBs. The current PCB recycling industry uses traditional metallurgical technologies in which the fiber reinforced polymer matrix materials are incinerated. Although great effort has been made in the traditional metallurgical technologies for increasing the recycling efficiency for the end-of-life electronic products, the PCB recycling industry still faces the problems of poor environmental performance and limited economic returns. Recently, under an EAGER grant, the PIs of this award demonstrated proof-of-concept preliminary work for developing a novel supercritical fluid (SCF) CO2-based PCB recycling process at relatively low/medium temperatures and pressures. The exploratory experiments demonstrated that PCBs are delaminated with metals and glass fiber maintain their original form, making it possible to increase recovery rates not only for precious metals but also for non-metal materials. Such a process opens a new dimension for recycling of PCB and provides the possibility of satisfying economical and environmental demands. In the current project, the research team will systematically investigate the delamination mechanism of the bonding materials in PCBs under supercritical fluid processes and seek to understand structure/process relationships. Although literature documents the application of supercritical fluids in polymer synthesis and processing, there is limited existing work on revealing the performance of polymeric materials in supercritical fluids. In addition, the research team will optimize the SCF process by implementing process conditions based on the mechanism study and systematically evaluate process performance. Finally, the team will model and validate the recycling process for scale-up in terms of cost, energy, and environmental impact. The team will collaborate with industrial collaborators to promote transferring fundamental research to practical application. In addition, research and education will be integrated throughout the entire project duration.