A new strategy for efficient chemical degradation and recycling of polyurethane materials: a multi-stage degradation method

Abstract

A new strategy of multi-stage degradation of PUFs attained gradient deconstruction of PUFs at low temperatures with low energy consumption.

Depolymerization within a Circular Plastics System

“…He et al combined an initial ammonolysis with a subsequent acidolysis, taking advantage of the increased reactivity of ammonolysis for milder conditions followed by acidolysis to yield suitably terminated polyols. 309 Dynamic polyurethane networks have been reported as a novel PU material type with enhanced chemical recyclability. 310 monomer, 25 °C, 4 h) of these thiourethanes shows their promise to circumvent the use of problematic isocyanates.…”

“…Under these conditions, competing esterification and other side reactions were disfavored by the lack of catalyst, solvent, and lower temperature used. He et al combined an initial ammonolysis with a subsequent acidolysis, taking advantage of the increased reactivity of ammonolysis for milder conditions followed by acidolysis to yield suitably terminated polyols …”

Multimethod Recyclable Thermoset Polybutadiene Polyurethane–Urea via Reversible Disulfide Bonds

“…Degradation–recycling of thermoset polyurethanes is mainly performed through chemical routes, such as alcoholysis, , aminolysis, acidolysis, , and hydrolysis . These processes can be used to recycle small molecules and low molecular oligomers containing amino or hydroxyl groups by breaking the urethane/urea bonds in the polyurethane network at high temperatures .…”

“…21 cystamine and tris(2-aminoethylamine), and the disulfide exchange in the main chain enabled the material to be reprocessed via hot-pressing at 150 °C for 30 min. 16 Degradation−recycling of thermoset polyurethanes is mainly performed through chemical routes, 5 such as alcoholysis, 22,23 aminolysis, 24 acidolysis, 25,26 and hydrolysis. 27 These processes can be used to recycle small molecules and low molecular oligomers containing amino or hydroxyl groups by breaking the urethane/urea bonds in the polyurethane network at high temperatures.…”

Chemical separation of polyurethane via acidolysis – combining acidolysis with hydrolysis for valorisation of aromatic amines

“…24–26 Nonetheless, the industrial acidolysis of PU, as implemented by H&S Anlagentechnik, Ikea, and Dow, 17 incorporates the diamines in the new lower value polyol, thereby circumventing separation and purifications steps. 27–33 Lastly, catalytic hydrogenation, 34–38 hydrolysis, 39–41 and solvolysis using tert -amyl alcohol all provide a mixture of polyol and aniline, which can be separated by e.g. liquid–liquid extraction.…”