Abstract

A plasticizer is a substance the addition of which to another material makes that material softer and more flexible. Most often plasticizers are materials which, when added to a polymer, cause an increase in the flexibility and workability, brought about by a decrease in the glass-transition temperature, T_g, of the polymer. The most widely plasticized polymer is poly(vinyl chloride) (PVC) due to its excellent plasticizer compatibility characteristics, and the development of plasticizers closely follows the development of this commodity polymer. This article provides an overview of the important types of plasticizers which exist, and gives details of manufacture and how different production methods and starting materials affect the properties of the plasticizers. The mechanism of action of plasticizers is described, in terms of plasticization theory and the chemical modifications that occur during this process, which account for the excellent performance of some plasticizer molecules and the apparently poor softening ability of others. These effects are used to make products that are familiar to daily life and a change of plasticizer can produce changes in the properties of a wallcovering, a cable sheathing, etc. The current legislative and toxicological status of plasticizers are thoroughly reviewed to provide information about the environmental effects of this widespread use of these products.