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

摘要

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 (NH_2)_2CO/CH_3CH_2OH 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 alue-added products including aromatic polyamines and polyether poiyols were retrieved. A feasible mechanism for degradation was proposed based on the NMR observations.