18 Questions
What is the trade name of the high tenacity and modulus fiber developed by DuPont in 1971?
Kevlar
What is the aromatic co-polyamide that appeared on the market towards the end of the 1980s, similar to Kevlar?
Twaron
What technique is used to prepare the polymer Nomex by low-temperature solution polymerization?
Solution polymerization
What is the solvent used for interfacial polymerization in the production of Nomex?
Solvent with limited water solubility
Why is it important to carry out the polymerization reaction of Nomex at low temperatures?
To avoid side reactions that produce unreactive ends
What can high temperatures during the polymerization of Nomex lead to?
Side reactions
What is the strength of Kevlar at cryogenic temperatures?
Maintains its strength and resilience
How does the tensile strength of Kevlar change at higher temperatures?
Reduced by about 10–20%
What happens to Kevlar's strength after 500 hours at 160°C (320°F)?
10% reduction in strength
At what temperature does Kevlar experience a 50% strength reduction after 70 hours?
260°C (500°F)
What are some applications of Para-aramids like Kevlar?
Used in brake linings, tyre reinforcement, composites for aircraft and protective clothing
Where are PPTA fibers, like Kevlar, commonly used?
In protective clothing like bulletproof vests and composites manufacturing
What is the basis for the high modulus versions of Kevlar and Twaron?
High crystallinity
How is radial crystalline orientation achieved in Para-aramid fibers?
Using the dry-jet wet-spinning process
What is the relationship between molecular orientation and fiber modulus in Para-aramid products?
Almost directly proportional
What are some properties of Kevlar related to insulation?
Good thermal insulation and electrical insulation
How does the strength of p-aramid fibers compare to steel?
5 times stronger
What is the dimensional stability like for aramid fibers?
Excellent
Test your knowledge on high performance fibers and polymers such as Kevlar®, Twaron®, and Meta Aramid. Explore topics including polymerization, modulus fiber development, and commercial applications.
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