Which polymer is useful as both a lubricant and an electrical insulator?

The condensation product of caprolactam is:

Orlon is a polymer of:

$R$ is one of the monomers for the formation of a polymer called

Which of the following properties is $NOT$ exhibited by $LDP$?

The structure given below is an example of
$I$. $A$ condensation and biodegradable polymer.
$II$. $A$ biodegradable and thermoplastic polymer.
$III$. $A$ biodegradable and thermosetting polymer.
$IV$. $A$ polyester and thermoplastic polymer.