A chain growth copolymer is (a) terylene (b) neoprene (c) nylon-6 (d) SBR

A chain growth copolymer is a type of copolymer that forms through a step-growth polymerization mechanism. In this process, monomers with reactive functional groups react with one another to form longer chains. The polymer chains grow in a sequential manner, with one monomer unit reacting with another until the polymer reaches its desired length.

Now, let's analyze each option and determine if it is a chain growth copolymer. (a) Terylene is a polyester formed through a condensation polymerization mechanism between ethylene glycol and terephthalic acid. This reaction is not a chain growth polymerization process, so Terylene is not a chain growth copolymer. (b) Neoprene is a type of synthetic rubber that forms through a free radical polymerization of chloroprene. This is a chain growth process, making Neoprene a chain growth copolymer. (c) Nylon-6 is a type of polyamide that forms through a polycondensation reaction between amino acids or lactams. This process does not involve a chain growth polymerization mechanism, so Nylon-6 is not a chain growth copolymer. (d) SBR (styrene-butadiene rubber) is formed through a free radical polymerization mechanism of the monomers styrene and butadiene. This is a chain growth process, making SBR a chain growth copolymer as well.

Based on our analysis, both Neoprene (option b) and SBR (option d) are examples of chain growth copolymers.