Ring-opening polymerization of cyclic carbonates

Guillaume, S. M., and Carpentier, J-F. Recent Advances in Metallo/Qrgano-Catalyzed Immortal Ring-Opening Polymerization of Cyclic Carbonates, Catal. Sci. Technol. 2 (2012) 898-906. 

Ariga, T., Takata, T., Endo, T., 1997. Cationic ring-opening polymerization of cyclic carbonates with alkyl halides to yield polycarbonate without the ether unit by suppression of elimination of carbon dioxide 1. Macromolecules 30, 737—744. 

Matsuo, J., Nakano, S., Sanda, F., Endo, T., 1998a. Ring-opening polymerization of cyclic carbonates by alcohol-acid catalyst. Journal of Polymer Science Part A Polymer Chemistry 36, 2463-2471. 

Several decades later, in the early 1930s, work (and interest) once more revived on aliphatic polycarbonates when Carothers and van Natta were able to produce low-melting, low-molecular-weight, microcrystalline aliphatic polycarbonates via two different synthetic pathways [27]. The first method was the transesterification of aliphatic dihydroxylic compounds with diethyl carbonate. The second approach was via ring-opening polymerization of cyclic carbonates of aliphatic dihydroxylic... 

The ring-opening polymerization of cyclic carbonates with polyfunctional amines forms poly (hydroxy 1-urethanes). The most traditional syntheses of cyclic carbonates use phosgene chemistry, which involves environmental hazard issues [100]. 

Here, lipase-catalyzed ring-opening polymerization of cyclic compounds giving polymers other than polyesters is described. l,3-Dioxan-2-one, six-membered cyclic carbonate, was polymerized in the presence of lipase catalysts (Fig. 13)... 

The cationic ring-opening polymerization of cyclic ethers has been the subject of many recent investigations (1.. Nuclear magnetic resonance (NMR) methods, particularly carbon-13 techniques, have been found most useful in studying the mechanism of these polymerizations ( ). In the present review we would like to report some of our recent work in this field. 

Conventional ring-opening polymerization of cyclic anhydrides, carbonates, lactones, and lactides require extremely pure monomers and anhydrous conditions as well as metallic catalysts, which must be completely removed before use, particularly for medical applications. To avoid these difficult restrictions, an enzymatic polymerization may be one of the more feasible methods to obtain the polyesters. This method was first reported by two independent groups (Kobayashi [152] and Gutman [153]) who showed that lipases, enzymes capable of catalyzing the hydrolysis of fatty acid esters, can polymerize various medium-sized lactones. 

In addition to step and chain polymerizations, another mode of polymerization is of importance. This is the ring-opening polymerization of cyclic monomers such as cyclic ethers, esters (lactones), amides (lactams), and siloxanes. Examples of commercially important types are given in Table 10.1. Of those listed, only the polyalkenes are composed solely of carbon chains. Those that have enjoyed the longest history of commercial exploitation are polyethers prepared from three-membered ring cyclic ethers (epoxides), polyamides from cyclic amides (lactams), and polysiloxanes from cyclic siloxanes. 

Aliphatic polysulfides with two or more carbon atoms per monomeric unit are accessible through ring opening polymerization of cyclic sulfides or by the addition of thiol groups onto vinyl groups. In these cases, the anionic polymerization of cyclic sulHdes differs substantially from that of cyclic ethers. The ethyl anion attacks the carbon atom in cyclic ethers. But in the ethyl lithium initiated polymerization of propylene sulfide, a lithium ethane thiolate is first formed, and its anion then starts the polymerization of propylene sulfide ... 

A last example to be mentioned here is the case of peculiar abnormal NHC (143) in which the carbene centre is no longer located between the nitrogen atoms but between nitrogen and carbon atoms. Compound (143) has been established as an efficient organocatalyst for ring-opening polymerization of cyclic esters.This report represents the first use of an abnormal NHC as catalyst in an organic transformation. 

Free-Radical Copolymerization of Vinyl Compounds with Unsaturated Heterocyclic Monomers. Free-radical ring-opening polymerization of cyclic ketenacetals and their nitrogen analogous occurs via formation of carbonyl bond at the expense of a less stable carbon-carbon double bond as depicted in Scheme 14 [49-56] ... 

The ring-opening polymerization of dilactide (dimeric cyclic ester of lactic acid) allows the preparation of high molecular weight, optically active polyesters of lactic acid. The configuration of the asymmetric carbon atoms of the monomer is retained when the polymerization is initiated with SnCl4 or Et2Zn, for example ... 

Among the more common thermoplastics from ring opening polymerization of interest in composite processing are polylactams, polyethers, polyacetals, and polycycloolefins. It has also been shown that polycarbonates can be produced from cyclic carbonates [22], Anionic ring opening polymerization of caprolactam to nylon 6 is uniquely suited to form a thermoplastic matrix for fiber-reinforced composites, specifically by the reaction injection pultrusion process [23-25]. The fast reaction kinetics with no by-products and the crystalline... 

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