Chemical recovery of thermosetting unsaturated polyester resins

Polymer materials are promoting the rapid development of society, but they cause serious environmental pollution and waste of resources due to improper treatment after disposal. Chemical recovery is becoming a promising solution since it can transform the waste polymers into useful chemicals or materials. However, it is a very big challenge to recover thermosetting resins due to their stable three-dimensional network structure. Uncontrolled degradation always leads to complex separation and low reutilization of degradation products. This review focuses on the progress in chemical recovery of most productive thermosetting unsaturated polyester resins (UPR) and highlights the efforts towards the selective breaking of ester bonds. It presents a new strategy of reconstruction-oriented recovery by which the degradation reaction is designed in combination with the reutilization of degradation products. We also give promising prospects for the chemical recovery of UPR. This review addresses advances and challenges in the chemical recovery of waste unsaturated polyester resins, presents a new strategy of reconstruction-oriented recovery, and gives promising prospects on the recovery of the wastes.