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1993 | Buch

Ionic Polymerization and Living Polymers

verfasst von: Michael Szwarc, Marcel Van Beylen

Verlag: Springer Netherlands

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Über dieses Buch

More than simply an up-to-date review of ionic polymerization, this book presents an in-depth and critical comparison of the anionic and cationic polymerization of vinyl monomers and heterocyclic compounds. These different modes of ionic polymerization are examined with regard to their capacity for producing living polymers. The concept of living polymers is re-examined and redefined in light of current knowledge of ionic polymerization and possible side reactions. Throughout, the authors offer perceptive insights into the basic concepts of polymerization chemistry and polymerization reaction mechanisms. The book begins with a review of ionic and radical polymerizations, the development of ionic polymerization, living and dormant polymers, and polymerizability. It goes on to consider important aspects of the structure and properties of ionic species; initiation and propagation of ionic polymerization; polymerization steps other than initiation or propagation, such as termination, isomerization, transfer, backbiting, and degraduation; and ionic copolymerization. Ionic Polymerization and Living Polymers is a much needed advanced text that will be widely read and referred to by polymer scientists, macromolecular chemists, and materials scientists.

Inhaltsverzeichnis

Frontmatter
1. Introduction
Abstract
Ionic polymerization, like the well-known radical polymerization, is a chain polyaddition. It starts with a reaction of a monomer with a species capable of forming an electrically charged or highly polar active group on the added monomer molecule. Interaction of this group with another molecule of the monomer results in the formation of a covalent bond linking these two species, and simultaneously regenerates the active group on the newly added molecule. Such a repetitive covalent bonding of the monomer molecules to the active end-group, and simultaneously the repeated regeneration of the latter on the added unit, produces a growing polymer chain.
Michael Szwarc, Marcel Van Beylen
2. Ionic Species
Abstract
Matter in bulk is electrically neutral and whenever it contains electrically charged species, i.e., ions or their aggregates, their opposite charges have to balance each other exactly. Conceptually, the simplest process converting electrically neutral molecules into electrically charged ions results from electron ejection (ionization) induced by photolysis or radiolysis (a process caused by the action of high-energy projectiles, e.g., γ rays, fast electrons, etc.). The ejected electrons are captured eventually by some neutral molecules yielding then the negative ions, while the ionized molecules constitute the positive ions.
Michael Szwarc, Marcel Van Beylen
3. Initiation and Propagation of Ionic Polymerization
Abstract
The process yielding the first species capable of being linked with a monomer molecule by a covalent bond while simultaneously endowing the added monomer unit with the activity associated with the initiator is the initiation of addition polymerization. The addition of an anion A - to a vinyl monomer CH2=CHX yielding a new A·CH2 CHX anion is an example of initiation of ionic polymerization. The addition of the next monomer molecule yields the same end-group but attached to a longer tail, i.e. A·CH2CHX·CH2 CHX. The sequence of the latter events constitutes the propagation of polymerization.
Michael Szwarc, Marcel Van Beylen
4. Elementary Steps of Polymerization Other Than Initiation or Propagation
Abstract
Propagation of polymerization continues until the activity of the growing ends of polymeric molecules is lost or the supply of monomer exhausted. The reactions that irreversibly deprive the growing polymeric molecules of their propensity for growth are known as terminations. They are classified as proper terminations resulting in cessation of all processes that consume the monomer by extending the length of the formed macro-molecules, and as chain-transfers—the events irreversibly terminating the propagation of some of the polymeric molecules growing at that time while simultaneously starting the growth of new ones. Both these processes should be distinguished from the formation of dormant polymers—the events temporarily terminating the growth of some polymeric molecules which, however, is resumed spontaneously at a later stage of the reaction.
Michael Szwarc, Marcel Van Beylen
5. Ionic Copolymerization
Abstract
A review of anionic copolymerization, covering the material available in 1968, was published by one of us.1 It dealt with the question of how to modify the concept of reactivity ratios to make it adaptable to ionic copolymerization, and how solvents and counterions affect the composition of the copolymers. Their magnitudes illustrated by Table 5.1 were surprising at that time.
Michael Szwarc, Marcel Van Beylen
Backmatter
Metadaten
Titel
Ionic Polymerization and Living Polymers
verfasst von
Michael Szwarc
Marcel Van Beylen
Copyright-Jahr
1993
Verlag
Springer Netherlands
Electronic ISBN
978-94-011-1478-3
Print ISBN
978-94-010-4649-7
DOI
https://doi.org/10.1007/978-94-011-1478-3