The key difference between homochain and heterochain polymer is that homochain polymer has its main chain made of the atoms of the same chemical element whereas heterochain polymer has its main chain made of atoms of different chemical elements.
A polymer is a macromolecular compound composed of a number of repeating units linked to each other via covalent chemical bonds. These are heavy materials with exceptional chemical and physical properties. There are many ways to classify polymer materials. Categorizing the polymers based on the nature of the backbone gives us two categories as homochain and heterochain polymers.
CONTENTS
1. Overview and Key Difference
2. What is a Homochain Polymer
3. What is a Heterochain Polymer
4. Side by Side Comparison – Homochain vs Heterochain Polymer in Tabular Form
5. Summary
What is a Homochain Polymer?
Homochain polymer is a type of polymer material in which the backbone of the polymer is made of atoms of the same chemical element. And, this term mainly applies to inorganic polymers.
Figure 01: A Homochain Polymer made of Sulfur Atoms in the Backbone
Furthermore, inorganic polymers are macromolecules made of many repeating units, and they do not include carbon atoms in their backbone (main chain). For example, polymeric sulfur contains only sulfur atoms in the backbone. E.g. polysilane.
What is a Heterochain Polymer?
Heterochain polymer is a type of polymer material in which the backbone of the polymer is made of atoms different chemical elements. Typically, there are two types of atoms arranged in an alternating pattern.
Heterochain polymers can be found in different types as follows:
- Si-based heterochain polymers: Polysiloxane polymers with Si and oxygen atoms in an alternating pattern are categorized into this group. Here, each Silicon base (Si-base) has two substituents: methyl and phenyl groups.
- P-based: Polyphosphazenes are categorized into this group. These polymer materials have phosphorous and nitrogen atoms making up the backbone of the polymer material. Here, the P and N atoms are in an alternating pattern.
Figure 02: A Heterochain Polymer with an Alternating Pattern of Phosphorous and Nitrogen Atoms in the Backbone. This is a P-based Heterchain Polymer.
- B-based: Polymers containing backbones with an alternating pattern of boron and nitrogen are classified as B-based heterochain polymers.
- S-based: Polythiazyls have a backbone of sulfur and nitrogen atoms in an alternating pattern. Unlike the other types, these polymers lack other substituents that are attached to the backbone.
What is the Difference Between Homochain and Heterochain Polymer?
There are many ways to classify polymer materials. Categorizing the polymers based on the nature of the backbone gives us two categories as homochain and heterochain polymers. The key difference between homochain and heterochain polymer is that homochain polymer has its main chain made of the atoms of the same chemical element, whereas heterochain polymer has its main chain made of atoms of different chemical elements. The most common examples of homochain polymers are polysilanes, while the common heterochain polymer materials include polysiloxanes, polyphosphazene, polythiazyls, etc.
The following infographic summarizes the difference between homochain and heterochain polymer.
Summary – Homochain vs Heterochain Polymer
Categorizing the polymers based on the nature of the backbone gives us two categories as homochain and heterochain polymers. The key difference between homochain and heterochain polymer is that homochain polymer has its main chain made of the atoms of the same chemical element, whereas heterochain polymer has its main chain made of atoms of different chemical elements.
Reference:
1. “Inorganic Polymer.” Wikipedia, Wikimedia Foundation, 15 Mar. 2020, Available here.
2. “Homochain Polymer (H02840).” IUPAC, Available here.
Image Courtesy:
1. “Selenium original” By Materialscientist at English Wikipedia (CC BY-SA 3.0) via Commons Wikimedia
2. “Polyphosphazene General Structure” By Author: Harry R. Allcock – HRAPSU (talk) (Uploads) (CC BY-SA 3.0) via Commons Wikimedia
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