Abstract
A solid-state polymerization can be treated as a special case of a phase change which may proceed homogeneously or heterogeneously. If solid-state chemistry is understood in its broadest sense, also such reactions may be considered which occur at the interphase between a gaseous educt and the crystalline product where e.g. each step of crystal growth occurs with formation of a chemical bond. In polymer science such reactions are called simultaneous polymerization and crystallization.