Comparing nylons: relative to nylon-66, nylon-6 is generally… (choose the correct statement).

Introduction / Context:
Nylon-6 and nylon-66 are two widely used polyamides with similar structures and overlapping applications. Subtle differences in melting point, abrasion resistance, and hardness influence material selection.

Given Data / Assumptions:

• Nylon-66 typically melts around 255–265 °C; nylon-6 around 215–225 °C.
• Nylon-66 often shows slightly higher stiffness, hardness, and abrasion resistance.
• Nylon-6 is noted for better dye uptake and impact at low temperatures.

Concept / Approach:
The higher melting point and crystallinity of nylon-66 stem from its even-numbered monomers (HMDA + adipic acid) enabling efficient hydrogen bonding and packing. Nylon-6 (from caprolactam) has lower Tm and generally slightly lower hardness and abrasion resistance relative to nylon-66.

Step-by-Step Solution:
Check melting point claim: nylon-6 does not exceed nylon-66 → (c) false.Check hardness/abrasion: nylon-66 commonly superior → (a) and (b) false.Thus, the correct choice among the given is “None of these.”

Verification / Alternative check:
Datasheets and handbooks consistently report nylon-66 higher Tm and often higher wear resistance; nylon-6 better dyeability.

Why Other Options Are Wrong:
(a), (b), (c) contradict typical property data.Option (e) is true in many cases, but it is not among the choices for the main selection—hence (d) fits the question’s intent.

Common Pitfalls:
Overgeneralising across grades filled with glass/minerals; mixing copolyamides with homopolymers.

Final Answer:
None of these