Robust thermoplastic polyurethane elastomers prepared from recycling polycarbonate

Abstract

Polymer properties along with recycling processes remain a constant challenge for post-recycled polymers. In this study, the development of recycling feasibility, monomers reactivity, and the chemical-recycled polymer properties from polycarbonate (PC) waste were demonstrated. Through selective aminolysis under mild conditions, the reduced molecular-weight products (or monomer mixtures) with newly incorporated flexible-ether linkages as building blocks were realized. By using the commodity monomers such as isocyanate reagents, monomer mixtures were readily to be re-connected into polyurethanes in one-pot process without prior purification of the recycled monomer mixtures. Due to the presence of urethane groups, the enhanced reactivity of the terminal phenolic hydroxyl groups of the monomer mixtures toward isocyanate groups would afford high molecular weights over ~80,000 g/mol for thermoplastic polyurethanes (TPUs). Moreover, by taking advantage of low melting point polyether-type polyols along with optimizing processing conditions, the TPUs exhibited a unique phase separation morphology with domain sizes ranging from ~10 nm to ~25 nm as investigated by using small angle X-ray scattering (SAXS) measurements. This work demonstrate that the PC waste was fully transformed into TPUs which exhibited improved elastomeric properties.