Harald Cherdron

Polymer Synthesis: Theory and Practice

Introduction.- Methods and Techniques for the Synthesis, Characterization, Processing and Modification of Polymers.- Synthesis of Macromolecular Substances by Addition Polymerization.- Synthesis of Macromolecular Substances by Condensation Polymerization and Stepwise Addition Polymerization.- - Modification of Macromolecular Substances.

Modification of Macromolecular Substances

The term “modification of macromolecular substances” is used for chemical and physical processes that are carried out after the actual synthesis, i.e., on the finished macromolecule. Chemical modifications are, for example, the conversion of ester side groups to hydroxy groups, chemical degradation and crosslinking reactions. Physical modifications are also of great importance in industrial practice. The utilization of additives to improve the processability (processing agents) or to increase the resistance to oxygen and light (oxidation inhibitors, photostabilizers) are among such modifications. Finally, there are some procedures to subsequently influence the mechanical properties of polymers above all. These include the admixing of inorganic fillers (“filled polymers”), the introduction of inorganic or organic fibers (“reinforced polymers”), the admixing of other polymers (“polymer blends”), as well as stretching and foaming.

Methods and Techniques for Synthesis, Characterization, Processing, and Modification of Polymers

In this chapter, the fundamentals and the most common methods and techniques for the synthesis, processing, characterization, and modification of macromolecular materials are described briefly, as an introduction to the special Chaps. 3, 4, and 5. The main emphasis is on the description of methods and techniques used in laboratories, but some examples from industrial practice are also mentioned.

Synthesis of Macromolecular Substances by Addition Polymerization

As already explained, polymerization reactions can proceed by various mechanisms and can be catalyzed by initiators of different kinds. For addition polymerization of single compounds, initiation of chains may occur via radical, cationic, anionic, or so-called coordinative-acting initiators, but some monomers will not polymerize by more than one mechanism. Both thermodynamic and kinetic factors can be important, depending on the structure of the monomer and its electronic and steric situation. The most important initiators are summarized in Table 3.1.