Polymers are thermoplastic or thermosetting according to their behavior with ris
ID: 1850363 • Letter: P
Question
Polymers are thermoplastic or thermosetting according to theirbehavior with rising and falling temperature. Which statement is correct?
a) Thermosetting polymers can be repeatedly softened and hardened by
heating and cooling cycles while thermoplastics can not.
b) Thermoplastic polymers become permanently hard when heated.
c) Thermoplastic polymers can be repeatedly softened and hardened by
heating and cooling cycles while thermosets can not.
d) Thermoplastics crosslink extensively during heating while
thermosetting polymers do not.
Explanation / Answer
Thermoplastics are commercially the most important of the three types, constituting around 70% of the tonnage of all synthetic polymers produced •Thermosets and elastomers share the remaining 30% about evenly, with a slight edge for the former •On a volumetric basis, current annual usage of polymers exceeds that of metals