Ring-opening polymerization

IUPAC definition

A polymerization in which a cyclic monomer yields a monomeric unit which is acyclic or contains fewer cycles than the monomer. Note: If monomer is polycyclic, the opening of a single ring is sufficient to classify the reaction as ring-opening polymerization.

Modified from the earlier definition.[1][2]

Penczek S.; Moad, G. Pure Appl. Chem., 2008, 80(10), 2163-2193

General scheme ionic propagation. Propagating center can be radical, cationic or anionic.

In polymer chemistry, ring-opening polymerization (ROP) is a form of chain-growth polymerization in which the terminus of a polymer chain attacks cyclic monomers to form a longer polymer (see figure). The reactive center can be radical, anionic or cationic. Some cyclic monomers such as norbornene or cyclooctadiene can be polymerized to high molecular weight polymers by using metal catalysts. ROP is a versatile method for the synthesis of biopolymers.

Ring-opening of cyclic monomers is often driven by the relief of bond-angle strain. Thus, as is the case for other types of polymerization, the enthalpy change in ring-opening is negative.[3]

  1. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "Ring-opening polymerization". doi:10.1351/goldbook.R05396
  2. ^ Jenkins, A. D.; Kratochvíl, P.; Stepto, R. F. T.; Suter, U. W. (1996). "Glossary of basic terms in polymer science (IUPAC Recommendations 1996)". Pure and Applied Chemistry. 68 (12): 2287–2311. doi:10.1351/pac199668122287.
  3. ^ Young, Robert J. (2011). Introduction to Polymers. Boca Raton: CRC Press. ISBN 978-0-8493-3929-5.