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Switchable catalysis improves the properties of co 2 -derived polymers: Poly(cyclohexene carbonate- b -ε-decalactone- b -cyclohexene carbonate) adhesives, elastomers, and toughened plastics

DOI: 10.1021/jacs.9b13106 DOI Help

Authors: Gregory S. Sulley (University of Oxford) , Georgina L. Gregory (University of Oxford) , Thomas T. D. Chen (University of Oxford) , Leticia Peña Carrodeguas (University of Oxford) , Gemma Trott (University of Oxford) , Alba Santmarti (Imperial College London) , Koon-Yang Lee (Imperial College London) , Nicholas J. Terrill (Diamond Light Source) , Charlotte K. Williams (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The American Chemical Society

State: Published (Approved)
Published: February 2020
Diamond Proposal Number(s): 23087

Open Access Open Access

Abstract: Carbon dioxide/epoxide copolymerization is an efficient way to add value to waste CO2 and to reduce pollution in polymer manufacturing. Using this process to make low molar mass polycarbonate polyols is a commercially relevant route to new thermosets and polyurethanes. In contrast, high molar mass polycarbonates, produced from CO2, generally under-deliver in terms of properties, and one of the most widely investigated, poly(cyclohexene carbonate), is limited by its low elongation at break and high brittleness. Here, a new catalytic polymerization process is reported that selectively and efficiently yields degradable ABA-block polymers, incorporating 6–23 wt % CO2. The polymers are synthesized using a new, highly active organometallic heterodinuclear Zn(II)/Mg(II) catalyst applied in a one-pot procedure together with biobased ε-decalactone, cyclohexene oxide, and carbon dioxide to make a series of poly(cyclohexene carbonate-b-decalactone-b-cyclohexene carbonate) [PCHC-PDL-PCHC]. The process is highly selective (CO2 selectivity >99% of theoretical value), allows for high monomer conversions (>90%), and yields polymers with predictable compositions, molar mass (from 38–71 kg mol–1), and forms dihydroxyl telechelic chains. These new materials improve upon the properties of poly(cyclohexene carbonate) and, specifically, they show good thermal stability (Td,5 ∼ 280 °C), high toughness (112 MJ m–3), and very high elongation at break (>900%). Materials properties are improved by precisely controlling both the quantity and location of carbon dioxide in the polymer chain. Preliminary studies show that polymers are stable in aqueous environments at room temperature over months, but they are rapidly degraded upon gentle heating in an acidic environment (60 °C, toluene, p-toluene sulfonic acid). The process is likely generally applicable to many other lactones, lactides, anhydrides, epoxides, and heterocumulenes and sets the scene for a host of new applications for CO2-derived polymers.

Journal Keywords: Catalysts; Inorganic carbon compounds; Plastics; Organic polymers; Polymers

Diamond Keywords: Plastics

Subject Areas: Chemistry, Materials

Instruments: I22-Small angle scattering & Diffraction

Added On: 24/02/2020 14:10


Discipline Tags:

Physical Chemistry Soft condensed matter physics Catalysis Chemistry Materials Science Metal-Organic Frameworks Polymer Science Metallurgy Organometallic Chemistry

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)