Nylon-6,6 is a condensation polymer used to make clothing fibres and parachute fabric. Explain why nylon-6,6 is described as a condensation polymer and outline the structural features of the monomers needed to form it.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Nylon-6,6 is made from two different monomers: hexanedioic acid (a dicarboxylic acid) and hexane-1,6-diamine (a diamine). It is widely used in textiles and engineering applications.
Model answer (5 marks)
Nylon‑6,6 is a condensation polymer because each time a monomer unit joins the growing chain a small molecule, water, is released.
The polymer is formed by repeated condensation reactions between the two monomers, giving a long chain backbone.
Both monomers are bifunctional, each possessing two reactive groups so that they can link to two other monomers.
Hexanedioic acid supplies two carboxylic acid (–COOH) groups.
Hexane‑1,6‑diamine supplies two amine (–NH₂) groups.
The –COOH groups of the acid react with the –NH₂ groups of the diamine to give an amide linkage (–CO–NH–) and release water.
The polymer is formed by repeated condensation reactions between the two monomers, giving a long chain backbone.
Both monomers are bifunctional, each possessing two reactive groups so that they can link to two other monomers.
Hexanedioic acid supplies two carboxylic acid (–COOH) groups.
Hexane‑1,6‑diamine supplies two amine (–NH₂) groups.
The –COOH groups of the acid react with the –NH₂ groups of the diamine to give an amide linkage (–CO–NH–) and release water.
Examiner tips
- Use the word "condensation" and mention water release; link each point to the marks; keep the answer concise and use the exact terminology (amide, bifunctional).
Common mistakes
- Forgetting to state that water is released; confusing the functional groups or not specifying both monomers; using vague terms like "link" instead of "amide linkage".
Mark scheme (5 marks)
- A small molecule (water) is released/eliminated each time a monomer unit joins the growing chain
- Monomers join together to form a longer chain / polymer backbone via repeated condensation reactions
- Each monomer must have two functional groups (bifunctional) so that it can bond to two other monomers / form a chain
- Hexanedioic acid provides two carboxylic acid (–COOH) groups
- Hexane-1,6-diamine provides two amine (–NH₂) groups, and the –COOH and –NH₂ groups react together to form an amide/peptide linkage (–CO–NH–)
Key terms in this question
Related
- All Edexcel A-Level Chemistry (9CH0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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