THE MORPHOLOGY OF SEMICRYSTALLINE POLYMERS

Polymeric material are now finding applications in all sectors of industry and, increasingly, inroads are being made into areas where other materials, such as glass or metals, have been used in the post. Although economic factors are inevitably playing their part in this expansion in the market for plastics, the development of new molecular architectures and novel processing routes are also opening up fresh possibilities for these materials in demanding, high technology applications. Ultimately, in polymers, as in other materials, the processing parameters chosen in a manufacturing process determine the structural features that develop within the final product and it is these same features that, ultimately, determine the macroscopic physical properties exhibited by the material. An understanding of morphology therefore at the heart of the development of materials and products with enhanced properties. However. potential applications are not the only reason,for the interest in polymer microstructure. Many polymers exhibit complex, hierarchical morphologies and much effort has been expended in attempting to understand the physical and chemical processes that occur in macromolecular systems. In this article, a survey is presented which covers the main structural elements associated with semi-crystalline polymers; molecular factors, crystal habits and polycrystalline structures are considered. In addition, some morphologies exhibited by less well ordered systems are also briefly described, as are the electron microscopy techniques that have made a major contribution to the development of current understanding.