Difference Between Homopolymer and Heteropolymer

Main Difference – Homopolymer vs Heteropolymer

Polymers are giant compounds made out of small basic units. These polymers are also called macromolecules. The building blocks of a polymer are called monomers. The process of producing a polymer through a monomer is called polymerization. Some polymers are made of the same type of monomers. These are called homopolymers. But some polymers are made of different types of monomers. They are called heteropolymers. Heteropolymers are also called copolymers when two types of monomers are involved in the polymerization process. The main difference between homopolymer and heteropolymer is that homopolymers are made from the polymerization of identical monomers whereas heteropolymers are made from the polymerization of two or more different monomers.

Key Areas Covered

1. What is a Homopolymer
      – Definition, Synthesis, and Properties of the Polymer with Examples
2. What is a Heteropolymer
      – Definition, Synthesis, and Properties of the Polymer with Examples
3. What are the Similarities Between Homopolymer and Heteropolymer
      – Outline of Common Features
4. What is the Difference Between Homopolymer and Heteropolymer
      – Comparison of Key Differences

Key Terms: Copolymer, Heteropolymer, Homopolymer, Monomer, Polymer, Polymerization, PVC, Polypropylene, Polystyrene, Thermoplastic

What is a Homopolymer

A homopolymer is a type of polymer that is made from identical monomers. Every basic unit of the polymer is similar to each other. A homopolymer is produced by the polymerization of the same type of monomers. This polymerization process is called homopolymerization.

There are a number of examples for homopolymers. All these are made out of a single type of monomer. The properties of homopolymers may vary with the type of monomer used in the polymerization.

Examples of Homopolymers

PVC

PVC or polyvinyl chloride is a homopolymer. It is produced by the polymerization of vinyl chloride monomer. It is a thermoplastic polymer. Therefore, it can be melted and molded for reuse several times.

Figure 1: Polymerization of vinyl chloride monomers give a homopolymer; polyvinyl chloride

Polystyrene

Polystyrene is another good example for homopolymers. The building block for polystyrene is styrene monomer.

Polypropylene

Polypropylene is a polymer made from propylene monomer. Therefore, it is a type of homopolymer. It is made by addition polymerization.

What is a Heteropolymer

A heteropolymer is a type of polymer that is made of two or more different types of monomers. If two monomers are involved in the polymerization process, the end product is called a copolymer. Copolymer is a type of heteropolymer. There are several types of copolymers.

• Alternating Copolymers
• Random Copolymers
• Block Copolymers
• Graft Copolymers

There are some polymers that are found in biological systems are heteropolymers. For example, DNA or any other polynucleotides are considered as heteropolymers. Polynucleotides are formed from different types of nucleotides. These nucleotides differ from each other according to the nitrogenous base that they are composed of. Proteins are also heteropolymers. Proteins are made of different types of amino acids.

Figure 2: A Polynucleotide

Examples of Heteropolymers

There are a number of examples for heteropolymers. Few are given below.

• SBS

SBS is a heteropolymer made from styrene monomers and buta-1,3-diene monomers. It is a block copolymer.

• Polycarbonate

Polycarbonate is a heteropolymer produced from the polymerization between bisphenol A and phosgene.

Similarities Between Homopolymer and Heteropolymer

• Homopolymer and heteropolymer are polymer materials.
• Both are made out of small molecules called monomers.
• Both types show linear polymer structures and branched structures.
• There are biomolecules that can be found as homopolymers and some other biomolecules are heteropolymers.

Difference Between Homopolymer and Heteropolymer

Definition

Homopolymer: Homopolymer is a type of polymer that is made from identical monomers.

Heteropolymer: Heteropolymer is a type of polymer that is made of two or more different types of monomers.

Number of Monomers Used

Homopolymer: A single type of monomer is used for the production of homopolymers.

Heteropolymer: More than one type of monomer is used for the production of heteropolymers.

Polymerization Process

Homopolymer: Homopolymers are produced by homopolymerization.

Heteropolymer: Heteropolymers are produced by copolymerization.

Conclusion

Homopolymers and heteropolymers are two broad categories of polymers. The chemical and physical properties of these polymers may vary according to the monomers used in the production. The main difference between homopolymer and heteropolymer is that homopolymers are made from the polymerization of identical monomers whereas heteropolymers are made from the polymerization of two or more different monomers.

References:

1.“Polymer Structures.” Virginia.edu, Available here. Accessed 28 Aug. 2017.
2.“Homopolymer.” Encyclopædia Britannica, Encyclopædia Britannica, inc., Available here. Accessed 28 Aug. 2017.

Image Courtesy:

1. “Polymerization of Vinyl Chloride to Polyvinyl Chloride” By Koh Wei Teck – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “DNA chemical structure” By Madprime (talk · contribs) – Own workiThe source code of this SVG is valid. This vector image was created with Inkscape.(CC BY-SA 3.0) via Commons Wikimedia