Overview of Polymeric Compounds

In the form of raw materials, polymers exhibit a wide range of compositions and properties. These properties can be enhanced or tuned to specific applications through the preparation of compounds. This section addresses three basic classes of polymers and the approaches for the preparation of compounds. 

Thermoplastics are polymers that can be melted, made into a desired form, and then re-melted. Thermoplastics can be processed into a desired shape through many processes, the most common of which are injection molding and extrusion. Blow molding, transfer molding, calendaring, casting, and other forming operations are all possible with thermoplastics. 

The properties that define polymers as an elastomer are that they must be amorphous when unstretched and must be above their glass transition temperature to be elastic. This can be compared to thermoplastics that must be crystalline or must be used below this temperature to preserve dimensional stability. 

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