High Performance Fibers and Polymers Quiz

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 Signup and view all the answers

Why is it important to carry out the polymerization reaction of Nomex at low temperatures?

To avoid side reactions that produce unreactive ends Signup and view all the answers

What can high temperatures during the polymerization of Nomex lead to?

Side reactions Signup and view all the answers

What is the strength of Kevlar at cryogenic temperatures?

Maintains its strength and resilience Signup and view all the answers

How does the tensile strength of Kevlar change at higher temperatures?

Reduced by about 10–20% Signup and view all the answers

What happens to Kevlar's strength after 500 hours at 160°C (320°F)?

10% reduction in strength Signup and view all the answers

At what temperature does Kevlar experience a 50% strength reduction after 70 hours?

260°C (500°F) Signup and view all the answers

What are some applications of Para-aramids like Kevlar?

Used in brake linings, tyre reinforcement, composites for aircraft and protective clothing Signup and view all the answers

Where are PPTA fibers, like Kevlar, commonly used?

In protective clothing like bulletproof vests and composites manufacturing Signup and view all the answers

What is the basis for the high modulus versions of Kevlar and Twaron?

High crystallinity Signup and view all the answers

How is radial crystalline orientation achieved in Para-aramid fibers?

Using the dry-jet wet-spinning process Signup and view all the answers

What is the relationship between molecular orientation and fiber modulus in Para-aramid products?

Almost directly proportional Signup and view all the answers

What are some properties of Kevlar related to insulation?

Good thermal insulation and electrical insulation Signup and view all the answers

How does the strength of p-aramid fibers compare to steel?

5 times stronger Signup and view all the answers

What is the dimensional stability like for aramid fibers?

Excellent Signup and view all the answers