Question

What makes linear and branched molecular structures behave like a thermoplastic polymer? Can cross-linked and network molecular structures also behave like thermoplastic polymers? Why or why not?

Answer 1

The difference between thermoplastic and thermoset types of polymers are described below.
Thermoplastic polymers undergo temporary changes when heated, so each time when you
re-heat again you can get a new form, that means they can be recycled. Linear molecules and
lightly branched molecules will come under this, as there are less restrictions for the flow of
the polymer under heat and pressure.
On the other hand thermoset polymers or 3D or cross-linked polymers undergo a permanent change
and cannot be modified or re-structured because of the strong covalent bonds which persist even
after heating. These covalent bonds are like a tug-of-war (just a metaphor), where molecules
try to pull each other but the rope does not break. Hence they cannot behave like thermoplastic
polymers.