Difference Between Amorphous and Crystalline Polymers

Main Difference – Amorphous vs Crystalline Polymers

Polymers are large macromolecules formed by joining a large number of smaller units called monomers. There are various types of polymer classifications. The most primary classification is based on the types of monomers that form the polymer. According to this classification, there are two types of polymers; (a) homopolymers, formed by the joining of single type of monomer (ex: polyvinyl chloride) and (b) heteropolymer, formed by the joining of two or more different types of monomer molecules (ex: poly (ethylene, propylene) copolymer). Another classification is based on the material properties of the polymer, namely; crystalline and amorphous. However, this classification is rather confusing because polymers can generally be both crystalline and amorphous. Although there are no 100% crystalline polymers, some polymers may be 100% amorphous under certain conditions. Polymer chains are arranged in  crystallized regions with specific patterns. Since there are no completely crystallised polymers, polymers with more crystalline regions are called semicrystalline polymers. Amorphous polymers are the polymers that have no crystalline regions and no uniformly packed molecules. Instead, amorphous regions of a polymer have randomly packed molecules with no sharp melting point. Thus, the main difference between amorphous and crystalline polymers is that amorphous polymers do not have uniformly packed molecules whereas crystalline polymers have uniformly packed molecules.

This article  describes,

1. What is Amorphous Polymer?

2. What is Crystalline Polymer?

3. Difference Between Amorphous and Crystalline Polymers

Difference Between Amorphous and Crystalline Polymers - Comparison Summary

What is Amorphous Polymer

Amorphous polymers are polymers that are composed of amorphous regions where molecules are randomly arranged. Polymers can be either completely amorphous or mixed with both amorphous and crystalline regions. Amorphous polymers possess widely different mechanical and physical properties owing to their structure and temperature. Below glass transition temperature (Tg), amorphous polymers exhibit glassy, hard and brittle properties. As the temperature is increased, while it passes the Tg, amorphous polymers form cross-links and show elastic properties. Tg is defined as the temperature at which the polymer becomes soft due to the long-range coordinated molecular motion. Natural rubber latex, styrene-butadiene rubber (SBR) are good examples of amorphous polymers below the glass transition temperature.

Difference Between Amorphous and Crystalline Polymers

What is Crystalline Polymer

Not a single polymer is crystalline because all the crystalline polymers contain considerable amounts of amorphous material. Thus, crystalline polymers are generally called semicrystalline polymers. Crystalline polymers show X-ray diffraction patterns due to the existence of specific partial patterns of molecules in the polymer chains and exhibit a crystalline melting temperature. X-ray diffraction, density measurements and heat of fusion are detected in order to determine the fraction of crystalline substances present in a particular polymer.

Difference Between Amorphous and Crystalline Polymers


Amorphous polymers are the polymers that contain amorphous regions where molecules are arranged randomly.

Crystalline polymers are the polymers with crystalline regions where molecules are arranged in a partial pattern.

Arrangement of Molecules

Amorphous polymers do not have uniformly packed molecules.

Crystalline polymers have uniformly packed molecules.

Melting Point

Amorphous polymers do not have a sharp melting point.

Crystalline polymers have a sharp melting point.


Amorphous polymers are transparent.

Crystalline polymers are opaque/ translucent.


Amorphous polymers have a low shrinkage.

Crystalline polymers have a high shrinkage.

Chemical Resistance

Amorphous polymers have a poor chemical resistance.

Crystalline polymers have a good chemical resistance.


Amorphous polymers are soft.

Crystalline polymers are hard.

Energy to Melt

Amorphous polymers have low energy.

Crystalline polymers have high energy.

Unlike crystalline polymers, amorphous polymers are brittle and glassy below Tg, while elastomeric above Tg.

Gas Permeability

Amorphous polymers have a high gas permeability.

Crystalline polymers have a low gas permeability.

Unlike amorphous polymers, crystalline polymers exhibit a melting transition temperature (Tm), glass transition temperature (Tg) and crystalline order.


Chalmers, J. M., & Meier, R. J. (Eds.). (2008). Molecular characterization and analysis of polymers. Amsterdam: Elsevier.
Giles, H. F., Wagner, J. R., & Mount, E. M. (2005). Extrusion: The definitive processing guide and handbook. Norwich, NY: William Andrew Pub.
Sperling, L. H. (1997). Polymeric multicomponent materials: An introduction. New York: Wiley.
Image Courtesy: 

“Amorphous vs Crystalline” By CPNikadee – Own work via

About the Author: Yashoda

Yashoda has been a freelance writer in the field of biology for about four years. He is an expert in conducting research related to polymer chemistry and nano-technology. He holds a B.Sc. (Hons) degree in Applied Science and a Master of Science degree in Industrial Chemistry.

Related pages

what is the difference between straightening and smoothing of hairchloroplast wikipediadefinition prepositional phraseinitiation of translation in prokaryotes and eukaryoteshetzel and gretelfungus vs yeast infectionam vs fm modulationstatic character examples in literaturerevenge hindi meaningrace culture and ethnicitywhats the difference between pansexual and bisexualdynamic round characterdefine omniscient narratordefinition of electrical insulatorwhat is the difference between miles and nautical milesdefinition cold bloodedhomophones vs homographsdifference between rmr and bmrleast count of micrometer caliperwhat is nucleolus functiondiploblastic definitioneagerly awaiting meaningnormative economics definitionromantics and victorianswhat are monounsaturated and polyunsaturated fatsnormal air pressure measured in kilopascalsrepetition anaphorathylakiodwhat is totipotentthe chemical name for vitamin cdistinguish between minerals and rocksproton neutronswhat does the parable of the good samaritan teach usconcept of diminishing marginal returnsassimilation child developmentchiral and achiral differenceinduction and orientation program for the new employeesorthopniainquiry enquiry differenceidiom or phrasedeoxyribose ribosegerman shepherd and alsatian differencedifference between dominant and recessive genesdifference between a nutritionist and dietitianexample of oxymoron in literaturewhat is the difference between ham and porkactivity based overhead rate formulahow to calculate polar moment of inertiamaltose molecular structureinfluences on modernismcytoplasm cytosolalpha helices and beta pleated sheetswhat is the meaning of cold blooded animalsapa citation footnotespredicate nomnativewhat is a noun or pronounis ia noun or pronounmeaning of confectionerwhat is the difference between etiquette and mannersrestraint deftracheostomy or tracheotomywhatisnounexamples of suspensions and colloidsisotonic definition chemistrystanzas and versesfunction of thylakoidironic satiredefine structuralism psychologydifference between cashmere and woolfeminism gender equalitydefine kinematics physicsbeta amylase