Compare nylon 6 with nylon 6,6: which property is generally lower for nylon 6?

Introduction / Context:
Nylon 6 (from caprolactam) and nylon 6,6 (from adipic acid and hexamethylene diamine) are closely related polyamides with similar mechanical profiles but different melting points and thermal stability. Knowing their differences guides fibre, film, and engineering plastic selection.

Given Data / Assumptions:

• Nylon 6 has a lower melting temperature (≈220–225°C) than nylon 6,6 (≈260–265°C).
• Thermal-oxidative stability and heat deflection are generally higher for nylon 6,6.
• Other properties may be grade-dependent and close in value.

Concept / Approach:
The amide group density and crystallinity differences give nylon 6,6 a higher melting point and better high-temperature strength retention than nylon 6. Thus, “thermal stability” is the most consistent differentiator. Abrasion resistance, adhesion, and hardness depend on specific formulations and can overlap significantly between the two.

Step-by-Step Solution:
Identify robust differentiator: melting point and heat resistance.Relate to stability: nylon 6,6 > nylon 6 for thermal stability.Select “thermal stability” as lower for nylon 6.

Verification / Alternative check:
Datasheets for unfilled grades consistently show higher melting point and higher heat deflection temperature for nylon 6,6.

Why Other Options Are Wrong:
Abrasion/adhesion/hardness: not universally lower; depend strongly on additives, conditioning, and processing.

Common Pitfalls:
Assuming a single property trend covers all grades; fillers and moisture conditioning influence mechanical data significantly.

Final Answer:
Thermal stability