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Crystallinity In Macromolecules

Macromolecules are giant polymer molecules made up of long chains of repeating molecular units and bonded

Name Composition Impurity Common color Crystal system
Diamond carbon   colorless and other cubic
Ruby aluminum oxide chromium red hexagonal
Sapphire aluminum oxide titanium, iron blue and other hexagonal
Emerald beryllium-aluminum silicate chromium green hexagonal
Jade calcium-magnesium-iron silicate iron green and other monoclinic
Opal silicon oxide hydrates (scattered light) various none
Topaz aluminum fluoride-hydroxide-silicate unknown colorless and other orthorhombic
Turquoise copper-aluminum-hydroxide-phosphate copper blue and other none
Zircon zirconium silicate iron colorless and other tetragonal

covalently to one another. Macromolecules occur widely in nature as carbohydrates, proteins, and nucleic acids. Polymers, plastics, and rubber also are macromolecules.

Macromolecules may be likened to a plate of spaghetti, in which the individual strands of the macro-molecules are entangled. Notably, there is a lack of order in this system, and a lack of crystallinity. However, a marked degree of order does exist in certain regions of these entanglements where segments of neighboring chains may be aligned, or where chain folding may promote the alignment of a chain with itself. Regions of high order in macromolecules, called crystallites, are very important to the physical and chemical properties of macromolecules. The increased forces of attraction between chains in these regions give the polymer strength, impact resistance, and resistance to chemical attack. Polymers can be subjected to some form of heat treatment followed by controlled cooling and, sometimes, stretching, in order to promote greater alignment of chains, a higher degree of crystallinity, and a consequent improvement in properties.

Additional topics

Science EncyclopediaScience & Philosophy: Cosine to Cyano groupCrystal - Common Classes Of Crystalline Solids, Internal Structures Of Metallic Crystals, Common Internal Structures Of Crystals Of Ionic Solids