Unit Overview

Polymers

CIE A-Level Chemistry· 5 min read 📊 n/a

1. Unit at a glance

Polymers are large macromolecules built from repeating smaller monomer units, divided into two main classes based on their formation mechanism. This unit starts with addition polymers, which build on your existing knowledge of alkene chemistry, then progresses to condensation polymers that include both common synthetic materials and important biological polymers.

This unit covers two core sub-topics outlined below:

Addition polymers

Learn how addition polymers form from alkene monomers, draw repeat units, and identify monomers from polymer structures.

★★⏱ 10 min

Condensation polymers

Explore condensation polymerisation of different monomer pairs, including polyesters, polyamides and natural biological polymers.

★★★⏱ 15 min

2. Common Pitfalls

Wrong move:

Confusing addition and condensation polymer types when analysing an unknown polymer structure

Why:

Addition polymers only have carbon in their backbone, while condensation polymers have heteroatoms from functional linkages

Correct move:

Check for ester/amide linkages (O/N in the backbone) to confirm a condensation polymer

Wrong move:

Including leaving group atoms in condensation polymer repeat units

Why:

Small molecules like water are eliminated during polymerisation and are not part of the repeating structure

Correct move:

Remove -OH from the acid end and -H from the alcohol/amine end when constructing the repeat unit

3. Quick Reference Cheatsheet

Concept	Key Rule/Structure
Addition polymerisation general form	$n CH_{2} = CHR \to - [CH_{2} - CHR]_{n} -$
Polyester linkage	$- COO -$
Polyamide linkage	$- CONH -$
Find addition polymer monomer	Split the carbon backbone to reform the alkene double bond on the monomer
Find condensation polymer monomer	Split the linkage, add -OH to the carbonyl end and -H to the O/N end

What's Next

Begin this unit with addition polymers to build your foundational knowledge of polymer structure and synthesis, then move on to the more complex condensation polymer topic, which is heavily featured in exam questions. After completing both sub-topics in this unit, you will be ready to progress to the next unit on organic synthesis.