Nomenclature check: polyhexamethylene adipamide is commonly known as which engineering polymer?

Introduction / Context:Engineering polymers are sometimes referred to by systematic chemical names and sometimes by industry trade names. Recognising equivalences avoids confusion in specifications and material selection.

Given Data / Assumptions:

• Polyhexamethylene adipamide forms from hexamethylene diamine (six carbons) and adipic acid (six carbons).
• Common trade/designation name is nylon-66.

Concept / Approach:The “66” in nylon-66 denotes the number of carbons in the diamine and diacid monomers, respectively. This contrasts with nylon-6, which is produced from a single monomer (caprolactam).

Step-by-Step Solution:Map the systematic name to monomers: hexamethylene (6) + adipamide (6 derived) → nylon-66.Exclude unrelated thermosets (Bakelite, epoxy) and elastomers (silicone rubber).

Verification / Alternative check:Standards and datasheets list nylon-66 with the chemical repeat unit derived from HMDA and adipic acid.

Why Other Options Are Wrong:Bakelite and epoxy: thermosets.Silicone rubber: polysiloxane elastomer.Polycarbonate: carbonate-linked thermoplastic; different chemistry.

Common Pitfalls:Confusing nylon-6 with nylon-66 due to similar naming.

Final Answer:Nylon-66