p. 563. General principles and historical aspects
- David J. WaltonDavid J. WaltonCoventry University
- and J. Phillip LorimerJ. Phillip LorimerCoventry University
Abstract
This chapter examines chain polymerization. This class of polymer accounts for a large proportion of the synthetic polymer industry and includes the large-tonnage materials such as polyethene, polystyrene, polyvinylchloride (PVC), and acrylics. The reaction mechanisms, which affect the build-up of polymer molar mass (RMM), and other factors are different for alkene polymers and polyurethanes. The alkene systems involve chain reaction mechanisms and the class of materials is called chain polymers. Chain polymers can be prepared in one of three ways. In free-radical polymerization, the alkene double bond opens homolytically. In cationic polymerization, an electron-deficient species removes both electrons from the electron-rich double bond. In anionic polymerization, a species more electron-rich than the double bond increases electron density of the π bonds such that heterolytic fission gives a negatively charged propagating chain end-group. The chapter then considers commercial chain polymer syntheses; the synthesis of monomers; and the properties of chain-growth polymers.
