Polymer materials — commercial name of polycaprolactam In industrial polymer science, polycaprolactam is commonly marketed under which fibre name used in textiles and engineering plastics?

Introduction / Context:
This question checks your understanding of polymer nomenclature and trade names, especially as used in the textile and engineering plastics industries. Many polymers have systematic chemical names as well as commercial names that appear on product labels.

Given Data / Assumptions:

• Polycaprolactam is the polymer formed by ring-opening polymerization of caprolactam.
• The options list common commercial fibres and plastics: nylon-6, nylon-66, dacron, and rayon.
• We assume standard industrial naming conventions.

Concept / Approach:
Nylons are polyamides. Nylon-6 comes from caprolactam, while nylon-66 is from hexamethylenediamine and adipic acid. Dacron is a trade name for polyethylene terephthalate (a polyester). Rayon is regenerated cellulose. Therefore, linking the correct commercial name requires recognizing the monomer and polymer family relationships.

Step-by-Step Solution:
Identify polycaprolactam → produced from caprolactam via ring-opening polymerization.Recall commercial naming: polycaprolactam is sold as nylon-6.Eliminate distractors: nylon-66 (different monomers), dacron (PET polyester), rayon (regenerated cellulose).

Verification / Alternative check:
Standard materials references and polymer textbooks uniformly equate polycaprolactam with nylon-6, used in fibres, films, and engineering parts (gears, bearings).

Why Other Options Are Wrong:

• nylon-66: a different polyamide made from adipic acid and hexamethylenediamine.
• dacron: PET polyester, not a polyamide.
• rayon: regenerated cellulose, not a synthetic polyamide.

Common Pitfalls:

• Confusing nylon-6 with nylon-66 because both are polyamides; the “6” vs “66” indicates monomer origin.

Final Answer:
nylon-6