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Amorphous Polymers

Amorphous Polymers are polymers that have no defined molecular structure, very similar to the molecular arrangement to molecules in a liquid. Some examples of these polymers include ABS, Polystyrene, Polyethylene therephthalate, (PET)

Structure of Amorphous Polymers

They are characterized by 2 to 3 dimensional structure, with chemical bonds between them, and they have a lot of randomness in the spatial arrangement of their molecules. They also have a "glassy" looking appearance, whilst crystalline polymers have an "opaque" looking structure due to the ordered arrangement in their crystal lattice. These features are quite different from that of a crystalline polymer, that which has a properly defined lattice structure, 3- dimensional and well-formed.

The arrangement of amorphous polymers greatly influences how the molecules react to different stress and strain impacts how the molecules of this material reacts to different influences such as shear stress, strain, boiling, heating, melting, etc. Because of this said instability, amorphous polymers are more unpredictable than their crystalline counterparts. Amorphous polymers have stronger resistance to mechanical impact, better than their crystalline counterparts. The structure of amorphous polymers can be studies more by using X-ray diffraction techniques, and electron scattering experiments. These experiments have shown the "noodle-like" appearance of amorphous polymers, and the structure of the amorphous polymer helps to absorb light, whilst that crystalline polymers scatters light due to the organisation in the crystal arrangement.

Structure of Amorphous polymer. Note the difference between the crystalline and Amorphous sections

Production and Processing of Amorphous Polymers

There are various methods used the production and processing of amorphous polymers. When making an amorphous polymer from polymer materials after undergoing the basic polymerisation chemical reactions necessary for producing a polymer from its primary monomer, the polymer has to undergo cooling at a super-fast rate, otherwise it will attain chemical equilibrium and becomes a crystalline polymer, and defeating the purpose to which it can be applied. Some of the methods used in the processing of amorphous polymers include Injection Moulding, Extrusion Moulding, Rotational Moulding, Thermoforming.

An injection moulder showing the injection mouding process

Applications of Amorphous Polymers

The varied uses of amorphous polymers cuts across major fields; home, and industrial. They offer greater cost effective alternatives to other materials, and they are very resistant to changes in mechanical stress and strain, and wear and tear. Acrylonitrile-butadiene-styrene (ABS) is very useful in making electrical products, refrigerator parts, gardening equipment and machinery. Acrylics (poly-methyl-methacrylate) can be used for enclosing aircrafts, optic materials like lenses. Fluorocarbons (PTFE or TFE) can be used for anti-corrosive sealing, making pipes and coatings. , anti-adhesive coatings, extreme temperature resistant electronic parts. Polyethylene is widely used in making kitchen wares such as plates, spoons, tumblers, battery parts, wrapping materials.

Amorphous polymers are also widely applied for various military applications especially in the US Military as a suitable replacement for other most costly machine and equipment parts. Amorphous polymers are well adapted for use as transparent armory materials, most especially the polycarbonates and the polyutheranes. They are also used in the preparation of bullets in guns, in particular the manufacture of sabot materials. These are majorly used in US Military to support the use of uranium penetrators. Because these materials also have good resistance to wear and tear and toughening, they are useful also as kinetic energy penetrators.