Terylene is a polymer obtained from

$PVC$ is prepared by the polymerization of:

An example of chain growth polymer is

The polymer $X$ consists of linear molecules and is closely packed. It is prepared in the presence of triethylaluminium and titanium tetrachloride under low pressure. The polymer $X$ is -

The species which can best serve as an initiator for the cationic polymerization is:

The thermosetting polymer Bakelite is formed by the reaction of phenol with which of the following?