Ring-opening polymerization

Stanislaw Penczek,Julia Pretula,Stanislaw Slomkowski

doi:10.1515/cti-2020-0028

Abstract

Abstract Ring-opening polymerization is defined by IUPAC (Penczek, S., Moad, G. (2008). Glossary of the terms related to kinetics, thermodynamics, and mechanisms of polymerization. (IUPAC Recommendations 2008), Pure and Applied Chemistry, 80(10), 2163–2193) as (cit.) “Ring-opening polymerization (ROP): Polymerization in which a cyclic monomer yields a monomeric unit that is either acyclic or contains fewer rings than the cyclic monomer”. The large part of the resulting polymerizations is living/controlled; practically all belong to chain polymerizations. After the introduction, providing basic information on chain polymerizations, the paper presents the concise overview of major classes of monomers used in ROP, including cyclic ethers, esters, carbonates, and siloxanes as well as cyclic nitrogen, phosphorus, and sulfur containing monomers. There are discussed also thermodynamics, kinetic polymerizability, and major mechanisms of ROP. Special attention is concentrated on polymers prepared by ROP on industrial scale.

Highlights

Polymers are macromolecules that are often compared to the string of pearls
Glossary of the terms related to kinetics, thermodynamics, and mechanisms of polymerization. (IUPAC Recommendations 2008), Pure and Applied Chemistry, 80(10), 2163–2193) as “Ring-opening polymerization (ROP): Polymerization in which a cyclic monomer yields a monomeric unit that is either acyclic or contains fewer rings than the cyclic monomer”
The most important monomers include cyclic ethers, esters, carbonates, amides, acetals, and cyclic siloxanes. These polymers have a number of properties not present in the vinyl polymers

Summary

Introduction

Polymers are macromolecules that are often compared to the string of pearls. there is a backbone, in which there are repeating units – former monomers. There are certain polymer molecules having the lower limit of the molar mass around 10,000 We are giving this number being aware, that there are large differences in required sizes, depending on the molecular structures. There are two large groups of monomers that form polymers via chain polymerization (Penczek & Pretula, 2012). These are monomers with multiple bonds, mostly vinyl compounds, like styrene or methyl methacrylate (Scheme 1) and cyclic compounds used in ROP. E.g., in anionic polymerization of ethylene oxide, initiated by an alcoholate anion (aka, alkoxide anion), ring opening regenerates the anion that becomes the active species (Slomkowski & Duda, 1993) Β-propiolactone was extensively studied in the 1960s and 70s but studies were stopped when it was found to be cancerogenic

H C O CH3

C CH2 H2

Findings

Concluding remarks