# Polymers

> CIE A-Level Chemistry · 9701
> Source: https://www.owlsprep.com/study/cie-9701-u24-overview/
> Weight: n/a

This unit introduces the classification, synthesis, structure, and applications of synthetic and natural polymers, a key organic chemistry topic with major industrial and biological relevance.

**Prerequisites:** Basic organic functional group chemistry; Alkene addition reactions; Condensation reactions of carboxylic acid derivatives

## Learning objectives

- Distinguish between addition and condensation polymerisation mechanisms and product structures
- Draw repeat units for common polymers and deduce monomer structures from given polymer chains
- Recognise key linkages in synthetic and natural polymers

## 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](https://www.owlsprep.com/study/cie-9701-u24-addition-polymers/) — Learn how addition polymers form from alkene monomers, draw repeat units, and identify monomers from polymer structures.
- [Condensation polymers](https://www.owlsprep.com/study/cie-9701-u24-condensation-polymers/) — Explore condensation polymerisation of different monomer pairs, including polyesters, polyamides and natural biological polymers.

## Common pitfalls

- **Wrong:** Confusing addition and condensation polymer types when analysing an unknown polymer structure
  - Why it fails: Addition polymers only have carbon in their backbone, while condensation polymers have heteroatoms from functional linkages
  - Correct: Check for ester/amide linkages (O/N in the backbone) to confirm a condensation polymer
- **Wrong:** Including leaving group atoms in condensation polymer repeat units
  - Why it fails: Small molecules like water are eliminated during polymerisation and are not part of the repeating structure
  - Correct: Remove -OH from the acid end and -H from the alcohol/amine end when constructing the repeat unit

## Cheatsheet

| Concept | Key Rule/Structure |
| --- | --- |
| Addition polymerisation general form | $n \text{CH}_2=\text{CHR} \rightarrow -[\text{CH}_2-\text{CHR}]_n-$ |
| Polyester linkage | $-\text{COO}-$ |
| Polyamide linkage | $-\text{CONH}-$ |
| 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.

- [Addition polymers](https://www.owlsprep.com/study/cie-9701-u24-addition-polymers/)
- [Condensation polymers](https://www.owlsprep.com/study/cie-9701-u24-condensation-polymers/)
- [Amino acids, proteins and DNA](https://www.owlsprep.com/study/cie-9701-u25-overview/)

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