Efficient and green catalytic degradation of high crosslinked rigid PU foam and recovery value-added products via selective cleavage of C–O and C–N bonds

Abstract

The degradation and recovery of waste rigid polyurethane foam (RPUF) have confronted enormous challenge because of its three-dimensional network. An efficient strategy was developed for chemical recycling of high value-added aromatic polyamines and polyether polyols via selective cleavage of carbamate and urea bonds from RPUF and characterized by Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Ray (FT-IR). The carbamate and urea bonds were readily cleaved using (NH2)2CO/CH3CH2OH as degradation system at 180 °C for 10 h. Nevertheless, the C–C bonds and C–O–C of ether linkages as framework structure remained intact in the degradation process. Eventually, the high value-added products including aromatic polyamines and polyether polyols were retrieved. A feasible mechanism for degradation was proposed based on the NMR observations.