Step 1: Understanding the Concept
Nylon polymers are named by the number of carbon atoms in their monomers. A single monomer with six carbons gives nylon 6.
Step 2: Reaction
Caprolactam is a seven-membered cyclic amide. Heating it with a little water opens the ring and the units join by amide linkages.
Step 3: Conclusion
The polymer formed is nylon 6, also called perlon.