Difference Between Amorphous Polymers and Crystalline Polymers

Main Difference

The main difference between amorphous polymers and crystalline polymers is that the amorphous polymers refer to the polymers which do not have uniformly packed molecules, whereas the crystalline polymers refer to the polymers which have uniformly packed molecules.

Amorphous Polymers vs. Crystalline Polymers

Amorphous polymers are the polymers which do not have uniformly packed molecules, whereas the crystalline polymers are the polymers which have uniformly packed molecules. Amorphous polymers have molecules that are arranged randomly that refer to the amorphous regions, whereas the crystalline polymers have molecules that are arranged in the definite patterns that refer to the crystalline regions. Amorphous polymers do not have definite or sharp melting points, whereas the crystalline polymers have definite and sharp melting points. Amorphous polymers are usually transparent and clear, whereas the crystalline polymers are usually translucent or opaque. Amorphous polymers usually have less chemical resistance, whereas the crystalline polymers usually have high chemical resistance. Amorphous polymers are usually soft, whereas the crystalline polymers are usually hard. Amorphous polymers usually have very low energy, whereas the crystalline polymers usually have very high energy. Amorphous polymers usually have a very high gas permeability, whereas crystalline polymers usually have a very low gas permeability. Amorphous polymers usually have a low shrinkage ability, whereas the crystalline amorphous usually have a high shrinkage ability.

Comparison Chart

Amorphous PolymersCrystalline Polymers
Amorphous polymers are the polymers which do not have uniformly packed molecules.Crystalline polymers are the polymers which have uniformly packed molecules.
Melting Point
No sharp melting pointSharp melting point
Clarity
TransparentOpaque
Shrinkage
Low shrinkageHigh shrinkage
Chemical Resistance
Poor chemical resistanceGood chemical resistance
Hardness
SoftHard
Energy to Melt
Low energyHigh energy
Gas Permeability
High permeabilityLow permeability

What are Amorphous Polymers?

Amorphous polymers are the polymers that have molecules that are arranged in a random manner that refer to the amorphous region. Amorphous polymers usually do not have packed molecules. Amorphous polymers also do not possess definite and sharp melting points. Amorphous polymers are usually clear, obvious and transparent. Amorphous polymers always have low shrinkage ability. Amorphous polymers usually have less chemical resistance. They are soft and have very low energy to melt. They also have very high permeability of gas. Due to structure difference, amorphous polymers usually have a very clear and different physical and mechanical properties. Amorphous polymers are very brittle, hard and glassy. Amorphous polymers always show elastic properties and also form cross-linkages. Amorphous polymers are soft usually due to long-ranged coordination. The behavior of amorphous polymers is that they become soft slowly as the temperature increases. Amorphous polymers have less dimensional stability and it can easily deform. Amorphous polymers are tough at low temperatures. It usually has the ability to creep down. Amorphous polymers usually have a low resistance to heat. The degree of order in the structure of amorphous polymers is random. This structure gives the amorphous polymers extra stability or different physical and mechanical properties. The structure of amorphous polymers is atactic. Amorphous polymers also have elasticity and flexibility. Amorphous polymers may also contain some areas or portions of crystallinity. Amorphous polymers usually have less clear appearance so they also cannot reflect the light.

Example

Natural rubber latex, Styrene-butadiene rubber, etc

What are Crystalline Polymers?

Crystalline polymers are the polymers that have molecules that are arranged in a regular manner that refer to the crystalline regions or portions. Crystalline polymers usually have packed molecules. The crystalline polymers also have sharp and definite fusion points. Crystalline polymers are always translucent and opaque. Crystalline polymers have a very high shrinkage ability. Crystalline polymers have a very high chemical resistance. They also have very high energy to melt. They also have a very low permeability of gases. Due to structure differences, crystalline polymers have very clear and different and unique physical and mechanical polymers. Crystalline polymers always show fewer elastic properties an also form tight cross-linkages. Crystalline polymers are very hard due to short-ranged coordination. Crystalline polymers have very high 3-D dimensional specific properties. Crystalline polymers also have a high abrasion to heat. The degree of order in the crystalline polymers is always regular. This structure crystalline polymer provides extra stability and specific properties such as physical and mechanical properties. The structure of crystalline polymers is also known as the tactic. Crystalline polymers have less elasticity and flexibility. Crystalline polymers always contain areas of crystallinity. Crystalline polymers have a full clear appearance and they have a clear appearance.

Example

Polyethylene, Polyethylene terephthalate, etc

Key Differences

  1. Amorphous polymers usually have amorphous regions, whereas the crystalline polymers usually have crystalline regions.
  2. Amorphous polymers do not have definite and sharp melting points, whereas the crystalline polymers have definite and sharp melting points.
  3. Amorphous polymers always have very high gas permeability, whereas the crystalline polymers always have very low gas permeability.
  4. Amorphous polymers have very low chemical resistance to heat, whereas the crystalline polymers have very high chemical resistance to heat.
  5. Amorphous polymers are usually soft, whereas the crystalline polymers are usually hard.
  6. Amorphous polymers are always very clear and transparent, whereas the crystalline polymers are always translucent and opaque.
  7. Amorphous polymers have very low shrinkage permeability, whereas the crystalline polymers have very high shrinkage ability.
  8. Amorphous polymers have high elasticity and flexibility, whereas the crystalline polymers have very low elasticity and flexibility.
  9. Amorphous polymers usually do not have packed molecules, whereas the crystalline polymers usually have packed molecules.

Conclusion

The above discussion concludes that both amorphous polymers and crystalline polymers are macromolecules. Amorphous polymers are the polymers that have molecules that are arranged in a random manner and have amorphous regions, whereas the crystalline polymers are the polymers that have molecules that are arranged in a regular manner and have crystalline regions.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss

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