A circular polyester platform based on simple gem-disubstituted valerolactones

Li, Xinlei; Clarke, Ryan W.; Jiang, Jingyang; Xu, Tao; Chen, Eugene Y.‐X.

doi:10.1038/s41557-022-01077-x

Cited by 64 publications

(54 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We envisioned another synergistic benefit of a,a-disubstitution that could endow the a,a-dialkylated PHA with chemical recyclability by direct depolymerization to its monomer, enabled by the gem-disubstituted Thorpe-Ingold effect that promotes ring closure and stabilization of strained rings (40)(41)(42)(43)(44). At the outset, depolymerization of a ROP-derived P3H(Me) 2 B sample was screened at temperatures below 240°C under vacuum with different base catalysts (table S2), affording (Me) 2 BL and sideproduct 2-methyl-2-butene with different ratios (fig.…”

Section: Dual Closed Loops To Achieve Chemical Circularitymentioning

confidence: 99%

Chemically circular, mechanically tough, and melt-processable polyhydroxyalkanoates

Zhou

Zhang

Shi

et al. 2023

Science

Self Cite

View full text Add to dashboard Cite

Polyhydroxyalkanoates (PHAs) have attracted increasing interest as sustainable plastics because of their biorenewability and biodegradability in the ambient environment. However, current semicrystalline PHAs face three long-standing challenges to broad commercial implementation and application: lack of melt processability, mechanical brittleness, and unrealized recyclability, the last of which is essential for achieving a circular plastics economy. Here we report a synthetic PHA platform that addresses the origin of thermal instability by eliminating α-hydrogens in the PHA repeat units and thus precluding facile cis-elimination during thermal degradation. This simple α,α-disubstitution in PHAs enhances the thermal stability so substantially that the PHAs become melt-processable. Synergistically, this structural modification also endows the PHAs with the mechanical toughness, intrinsic crystallinity, and closed-loop chemical recyclability.

show abstract

Section: Dual Closed Loops To Achieve Chemical Circularitymentioning

confidence: 99%

Chemically circular, mechanically tough, and melt-processable polyhydroxyalkanoates

Zhou

Zhang

Shi

et al. 2023

Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…Plastics released to the environment can persist for many decades or longer. Even in conjunction with a more responsible, circular plastics econonomy, degradability is desirable as a backstop to plastic accumulation in the environment. − The degradation rates of polymer materials depend strongly on their specific environment. Especially rates of biodegradation vary enormously depending on the microbial environment .…”

Section: Introductionmentioning

confidence: 99%

Polyethylene-Like Blends Amenable to Abiotic Hydrolytic Degradation

Eck

Bernabeu

Mecking

2023

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

18) exhibits high density polyethylene-like material properties and, as opposed to high density polyethylene (HDPE), can be recycled in a closed loop via depolymerization to monomers under mild conditions. Despite the in-chain ester groups, its high crystallinity and hydrophobicity render PE-18,18 stable toward hydrolysis even under acidic conditions for one year. Hydrolytic degradability, however, can be a desirable material property as it can serve as a universal backstop to plastic accumulation in the environment. We present an approach to render PE-18,18 hydrolytically degradable by melt blending with long-chain aliphatic poly(H-phosphonate)s (PP). The blends can be processed via common injection molding and 3D printing and exhibit HDPE-like tensile properties, namely, high stiffness (E = 750−940 MPa) and ductility (ε tb = 330−460%) over a wide range of blend ratios (0.5−20 wt % PP content). Likewise, the orthorhombic solid-state structure and crystallinity (χ ≈ 70%) of the blends are similar to HDPE. Under aqueous conditions in phosphate-buffered media at 25 °C, the blends' PP component is hydrolyzed completely to the underlying long-chain diol and phosphorous acid within four months, as evidenced by NMR analyses. Concomitant, the PE-18,18 major blend component is partially hydrolyzed, while neat PE-18,18 is inert under identical conditions. The hydrolysis of the blend components proceeded throughout the bulk of the specimens as confirmed by gel permeation chromatography (GPC) measurements. The significant molar mass reduction upon extended immersion in water (M n (virgin blends) ≈ 50−70 kg mol −1 ; M n (hydrolyzed blends) ≈ 7−11 kg mol −1 ) resulted in embrittlement and fragmentation of the injection molded specimens. This increases the surface area and is anticipated to promote eventual mineralization by abiotic and biotic pathways of these HDPE-like polyesters in the environment.

show abstract

“…CO2/OX ROCOP. 60 Here, cyclic trimethylenecarbonate by-products are formed due to establishing (de)polymerisation equilibria between poly(trimethylenecarbonate) and the cyclic six-membered carbonates. 45,[61][62][63][64] As this observation is most pronounced in geminally disubstituted derivatives due to the Thorpe-Ingold effect, we compared the relative energies of formation of the carbonate polymer carbonate P and the cyclic carbonate C from OX Me and CO2 as well as the alternating dithiocarbonate polymer P T and the cyclic dithiocarbonates C T from OX Me and CS2 on the B3LYP/cc-pVDZ level of theory (Figure 5(a1/2)) with periodic boundary conditions for P and P T (ESI Section S11), i.e.…”

Section: Resultsmentioning

confidence: 99%

Cooperative taming of CS2/oxetane copolymerisation: Consequences of main-chain sulfuration on polymer properties and catalysis

Plajer

Fornacon-Wood

Gallizioli

et al. 2023

Preprint

View full text Add to dashboard Cite

CS2 promises easy access to degradable sulfur-rich polymers and insights into how main-group derivatisation affects polymer formation and properties, though its ring-opening copolymerisation is plagued by low linkage selectivity and small-molecule by-products. We demonstrate that a cooperative Cr(III)/K catalyst selectively delivers poly(dithiocarbonates) from CS2 and oxetanes while state-of-the-art strategies produce linkage scrambled polymers and heterocyclic by-products. The formal introduction of sulfur centres into the parent polycarbonates results in a net shift of the polymerisation equilibrium towards, and therefore facilitating, depolymerisation. During copolymerisation however the catalyst enables near quantitative generation of the metastable polymers in high sequence selectivity by limiting the lifetime of alkoxide intermediates. Furthermore, linkage selectivity is key to obtain semi-crystalline materials that can be moulded into self-standing objects. Our report demonstrates the potential of cooperative catalysis to produce previously inaccessible main-group rich materials with beneficial chemical and physical properties

show abstract

A circular polyester platform based on simple gem-disubstituted valerolactones

Cited by 64 publications

References 58 publications

Chemically circular, mechanically tough, and melt-processable polyhydroxyalkanoates

Chemically circular, mechanically tough, and melt-processable polyhydroxyalkanoates

Polyethylene-Like Blends Amenable to Abiotic Hydrolytic Degradation

Cooperative taming of CS2/oxetane copolymerisation: Consequences of main-chain sulfuration on polymer properties and catalysis

Contact Info

Product

Resources

About