Versatile Chemical Recycling Strategies: Value‐Added Chemicals from Polyester and Polycarbonate Waste

Abstract

ZnII‐complexes bearing half‐salan ligands were exploited in the mild and selective chemical upcycling of various commercial polyesters and polycarbonates. Remarkably, we report the first example of discrete metal‐mediated poly(bisphenol A carbonate) (BPA‐PC) methanolysis being appreciably active at room temperature. Indeed, Zn(2)2 and Zn(2)Et achieved complete BPA‐PC consumption within 12–18 mins in 2‐Me‐THF, noting high bisphenol A (BPA) yields (SBPA=85–91 %) within 2–4 h. Further kinetic analysis found such catalysts to possess kapp values of 0.28±0.040 and 0.47±0.049 min−1 respectively at 4 wt%, the highest reported to date. A completely circular upcycling approach to plastic waste was demonstrated through the production of several renewable poly(ester‐amide)s (PEAs), based on a terephthalamide monomer derived from bottle‐grade poly(ethylene terephthalate) (PET), which exhibited excellent thermal properties.

Trends in Polyester Upcycling for Diversifying a Problematic Waste Stream

“…Not only does this require better collection and sorting, but technological breakthroughs in terms of catalytic efficiency in recycling/upcycling are critically important. 40,50,94,139 Ingenuity in labeling of bottles, for example, can lead to improved sorting capabilities and therefore increase the rate at which this large postconsumer source is collected and effectively reutilized. 140 There also deserves to be significant development in terms of reutilizing particular sources of postconsumer polyesters.…”

Homoleptic phenoxy-imine pyridine zinc complexes: efficient catalysts for solvent free synthesis and chemical degradation of polyesters

“…In this context, discrete homogeneous metal complexes with defined structures may offer great opportunities but they are still poorly investigated as catalysts. 37–41…”

“…In this context, discrete homogeneous metal complexes with defined structures may offer great opportunities but they are still poorly investigated as catalysts. [37][38][39][40][41] Recently, several homoleptic zinc complexes stabilized by monoanionic (NNO) ligands have been reported by Jones as efficient catalysts for the synthesis and alcoholysis of PLA. [42][43][44] For these systems the neutral amine of the ligands seems to have a crucial role in assisting the depolymerization via H bond activation of the alcohol.…”

Upcycling of polyester wastes blended bio-based alginate fiber to fire-safety composite applied in the construct field

“…Alternatively, the industrial engineering as an ideal process to recover textile waste has been largely overlooked, which may offer an imperative strategy to realize the PET waste ber upcycling. Currently, the waste management of PET product is mainly using the traditional chemical process to separate, purify and produce PET monomer or long chain polymer 11,12 , during which treating process includes enzymatic degradation method 13,14 , acid treatment coupling with mechanical treatment 15 , glycolysis along with microwave irradiation 13,16 , aminolysis and electron beam radiations [17][18][19] . The chemical recovery strategy indeed yields a good result in the recycling PET waste ber or fabric, assisting to environment pollution reduction compared with the land ll or incineration.…”