ABSTRACT
This chapter aims to present some unifying thoughts on the “why’s” and “how’s” of multiphase systems. It examines specific techniques for utilizing discrete phases and considers the factors that go into choosing a technique and give some examples of the technique. Multiphase materials are usually developed in order to give combinations of properties that are superior to single component materials. These properties can include toughness, heat distortion, processability, cost, or any of a host of other properties we deem necessary. Three basic mechanisms of energy absorption are available within a single material: shear yielding, crazing, and crack formation. Special structures can be produced via clever polymerization or processing, in which an intrinsically tough material forms a continuous layer or network. Dispersions of toughening agents are used to nucleate whatever energy-absorbing mechanism is available. Frequently, this will be crazing or shear banding in thermoplastics and multiple crack formation in thermosets.
