amorphous

Examples of amorphous in the following topics:

• Amorphous Solids

  • Solids can be divided into two classes: crystalline and amorphous.
  • Most amorphous solids have some short-range order.
  • However, amorphous solids are common to all subsets of solids.
  • Samples of amorphous metallic glass are shown below.
  • Most classes of solid can be found in an amorphous form.

• Characteristics of Condensation Polymers

  • The high Tg and Tm values for the amorphous polymer Lexan are consistent with its brilliant transparency and glass-like rigidity.
  • This cold-drawing procedure organizes randomly oriented crystalline domains, and also aligns amorphous domains so they become more crystalline.
  • This contrasts with elastomeric polymers, for which the stretched or aligned morphology is unstable relative to the amorphous random coil morphology.
  • Step-growth polymerization is also used for preparing a class of adhesives and amorphous solids called epoxy resins.

• Properties of Macromolecules

  • In some cases the entire solid may be amorphous, composed entirely of coiled and tangled macromolecular chains.
  • Natural rubber is a completely amorphous polymer.
  • The following illustration shows a cross-linked section of amorphous rubber.
  • Tg is the temperature below which amorphous domains lose the structural mobility of the polymer chains and become rigid glasses.
  • Elastomers are amorphous polymers that have the ability to stretch and then return to their original shape at temperatures above Tg.

• Aluminosilicates

  • These can be found as synthetic, amorphous, sodium aluminosilicates, a few naturally-occurring minerals, and synthetic zeolites.
  • Synthetic, amorphous, sodium aluminosilicate is widely used as a food additive, E-554.

• Thermosetting vs. Thermoplastic Polymers

  • Lignin is the amorphous matrix in which the cellulose fibers of wood are oriented.

• Properties of Carbon

  • Allotropes of carbon are not limited to diamond and graphite, but also include buckyballs (fullerenes), amorphous carbon, glassy carbon, carbon nanofoam, nanotubes, and others.
  • Some allotropes of carbon: a) diamond, b) graphite, c) lonsdaleite, d–f) fullerenes (C60, C540, C70); g) amorphous carbon, h) carbon nanotube.

• Allotropes of Carbon

  • Even though amorphous carbon can be manufactured, there still exist some microscopic crystals of graphite-like or diamond-like carbon.
  • The properties of amorphous carbon depend on the ratio of sp2 to sp3 hybridized bonds present in the material.
  • Materials that are high in sp3 hybridized bonds are referred to as tetrahedral amorphous carbon (owing to the tetrahedral shape formed by sp3 hybridized bonds), or diamond-like carbon (owing to the similarity of many of its physical properties to those of diamond).

• Radical Chain-Growth Polymerization

  • As a result, the morphology of LDPE is an amorphous network of highly branched macromolecules.

• Properties of Phosphorus

  • Phosphorus after this treatment is amorphous.

• Properties of Quartz and Glass

  • Glass is an amorphous (non-crystalline) solid material.