Chemistry of ring-opening polymerizations

Formation of polymers through ring-opening reactions of cyclic compounds is an important process in polymer chemistry. In such polymerizations, chain-growth takes place through successive additions of the opened structures to the polymer chain  

An example of the above is a ring-opening polymerization of ethylene oxide that results in formation of poly (ethylene oxide), a polyether  

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The mechanism of ring-opening polymerization has received much attention in recent years. The studies of it has made control of the polymerization reactions possible resulting in desirable products. However, many problems still remain unsolved in this field. In fact, the situation is far less satisfactory than the fields of vinyl polymerization and polycondensation. Extensive studies of copolymerization should be useful for the establishment of the chemistry of ring-opening polymerization. 

This chapter reviewed the chemistry of ring opening polymerization of cyclic monomers that yield thermoplastic polymers of interest in composite processing. In addition, this chapter focuses on the chemistry, kinetics, and rheology of the ring opening polymerization of caprolactam to nylon 6. Finally, these rheokinetics models are applied to the reactive injection pultrusion (RIP) process. 

At a recent symposium in his honour, Bailey reviewed the theory and chemistry of ring-opening polymerizations with expansion in volume. Monomers in... 

Riva R, Schmeits S, Jerome C, Jerome R, Lecomte P (2007) Combination of ring-opening polymerization and click chemistry toward functionalization and grafting of poly( -caprolactone). Macromolecules 40 796-803... 

Rao, J., Zhang, Y., Zhang, J., Lin, S. (2008). Facile preparation of well-defined AB2 Y-shaped Miktoarm star polypeptide copolymer via the combination of ring-opening polymerization and chck chemistry. Biomacromolecules, 9, 2586-2593. 

Peng, S.-M., Chen, Y, Hua, C. etal. (2009) Dendron-hkepolypeptide/hnearpolyfethylene oxide)biohybiids with both asymmetrical and symmetrical topologies synthesized via the combination of click chemistry and ring-opening polymerization. Macromolecules, 42,104-113. 

Scheme 10 Mechanism of ring-opening polymerization of cyclic vinyl ethers (23). Reproduced from Moad, G. Rizzardo, E. Thang, S. H., Radical addition-fragmentation chemistry in polymer synthesis. Po/ymer2008, 49,1079-1131." ...

Nylon-6 is the polyamide formed by the ring-opening polymerization of S-caprolactam. The polymerization of S-caprolactam can be initiated by acids, bases, or water. Hydrolytic polymerization initiated by water is often used in industry. The polymerization is carried out commercially in both batch and continuous processes by heating the monomer in the presence of 5—10% water to temperatures of 250—280°C for periods of 12 to more than 24 h. The chemistry of the polymerization is shown by the following reaction sequence. 

The chemistry of polymerization of the oxetanes is much the same as for THE polymerization. The ring-opening polymerization of oxetanes is primarily accompHshed by cationic polymerization methods (283,313—318), but because of the added ring strain, other polymerization techniques, eg, iasertion polymerization (319), anionic polymerization (320), and free-radical ring-opening polymerization (321), have been successful with certain special oxetanes. 

Polylactides, 18 Poly lactones, 18, 43 Poly(L-lactic acid) (PLLA), 22, 41, 42 preparation of, 99-100 Polymer age, 1 Polymer architecture, 6-9 Polymer chains, nonmesogenic units in, 52 Polymer Chemistry (Stevens), 5 Polymeric chiral catalysts, 473-474 Polymeric materials, history of, 1-2 Polymeric MDI (PMDI), 201, 210, 238 Polymerizations. See also Copolymerization Depolymerization Polyesterification Polymers Prepolymerization Repolymerization Ring-opening polymerization Solid-state polymerization Solution polymerization Solvent-free polymerization Step-grown polymerization processes Vapor-phase deposition polymerization acid chloride, 155-157 ADMET, 4, 10, 431-461 anionic, 149, 174, 177-178 batch, 167 bulk, 166, 331 chain-growth, 4 continuous, 167, 548 coupling, 467 Friedel-Crafts, 332-334 Hoechst, 548 hydrolytic, 150-153 influence of water content on, 151-152, 154... 

Cypryk, M. Chojnowski, J. Kurjata, J. Tertiary Trisilyloxonium Ion and Silylenium Cation in Cationic Ring-opening Polymerization of Cyclic Siloxanes. In Organosilicon Chemistry VI From Molecules to Materials Auner, N., Weis, J., Eds. Wiley-VCH Weinheim, 2005 pp 85-92. 

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