Ren-Jian Wei

Functional poly(carbonate-co-ether) synthesis from glycidyl methacrylate/CO2 copolymerization catalyzed by Zn–Co(III) double metal cyanide complex catalyst

Polycarbonates with pendant functional groups have attracted much attention due to their capability for further chemical modification and post-polymerization. This work describes the synthesis of a poly(carbonate-co-ether) with massive pendant acrylate groups from the copolymerization of glycidyl methacrylate (GMA) with carbon dioxide (CO2), using a nanolamellar zinc-cobalt double metal cyanide complex (Zn–Co(III) DMCC) catalyst. The carbonate linkage content (FCO2) of the poly(carbonate-co-ether) could be varied from 42.2 to 68.0% by changing the polymerization conditions. Of importance, 4-methoxyphenol was applied for regulating the copolymerization. It could not only act as an inhibitor for completely depressing the self-polymerization of GMA via free radical polymerization of the double bond, but also modulate the molecular weight of the resultant copolymers. The obtained copolymer had two terminal hydroxyl groups, which were confirmed by the electrospray ionization-tandem mass spectrometry (ESI-MS) technique. A new thermoset with high glass transition temperature (Tg: 105 or 120 °C) and massive carbonate units as well as hydroxyl (or carboxylic) groups was prepared by the curing reaction of the GMA–CO2 copolymer with allyl alcohol or acrylic acid in the presence of 2,2′-azobisisobutyronitrile (AIBN).

Synthesis of bis(cyclic carbonate) and propylene carbonate via a one-pot coupling reaction of CO2, bisepoxide and propylene oxide

The effective transformation of carbon dioxide (CO2) into valuable products is promising in green and sustainable chemistry. The coupling reaction of CO2 with epoxides to afford cyclic carbonates is an atom-economic pathway for CO2 fixation. Many catalysts have been developed for this coupling reaction, however, very few of them were reported for the coupling reaction of CO2 with bisepoxides. This work describes an efficient one-pot coupling reaction of CO2, propylene oxide (PO) and bisepoxides without the addition of external organic solvents by using a nanolamellar zinc-cobalt double metal cyanide complex (Zn–Co(III) DMCC) as the catalyst and cetyltrimethyl-ammonium bromide (CTAB) as the co-catalyst. Propylene carbonate (PC) and bis(cyclic carbonate)s were obtained at the same time with high monomer conversions (PO: 93.6%, bisepoxides: 82.9%). The in situ produced PC acted as a good solvent for the coupling reaction of CO2 with bisepoxides. Two products could be easily separated by distillation or precipitation. The application of the obtained bis(cyclic carbonate)s was also preliminarily investigated. A non-isocyanate route for synthesizing polyurethanes with massive hydroxyl groups was proposed.

Synthesis of fully alternating polycarbonate with low Tg from carbon dioxide and bio-based fatty acid

The selective copolymerization of CO2 and an epoxide to form fully alternating polycarbonates is a great challenge via catalysis with the zinc–cobalt(III) double metal cyanide complex [Zn–Co(III) DMCC]. We describe the first perfectly alternating copolymerization of CO2 with a bio-based epoxide. The resultant polycarbonate had a low Tgs of −38 to −44 °C and two end hydroxyl groups, which were then used to initiate ring-opening polymerization of L-lactide via metal-free catalysis, affording a biodegradable triblock copolymer. This study provides a new platform copolymer for making various advanced polymers with biodegradable properties.

Regio-selective synthesis of polyepichlorohydrin diol using Zn–Co(III) double metal cyanide complex

A simple one-pot ring-opening polymerization (ROP) of epichlorohydrin (ECH) was successfully performed by a heterogeneous Zn–Co(III) double metal cyanide complex (Zn–Co(III) DMCC) catalyst, affording regio-regular poly(ECH) diol with a head-to-tail content of >99% in the absence of organic solvent and/or protic compound. No cyclic or oligomer by-product was observed, and the employed Zn–Co(III) DMCC catalyst was recyclable. ROP of (R)- or (S)-ECH led to the generation of semi-crystalline poly(ECH) diol with a melting point of 81 °C or 102 °C, respectively. These regio-regular poly(ECH)s with two end hydroxyl groups are versatile platforms for ECH-based functionalized polymers.