Which initiator is used for the free radical addition polymerization process?

The Ziegler-Natta catalyst used for polymerisation of ethene and styrene is $TiCl_4 + (C_2H_5)_3Al$. The catalysing species (active species) involved in the polymerisation is

The straight chain polymer is formed by

Which monomer is used for the preparation of Orlon?

Out of chain growth polymerization and step growth polymerization,in which type will you place the following reaction: $-(A)_m + -(A)_n \to -(A)_{m+n}$?

Explain the preparation of Nylon-$2$-nylon-$6$.