$P• + XR' \rightarrow PX + R'•$: Chain transfer is a polymerization reaction by which the activity of a growing polymer chain is
Chain transfer reactions reduce the average molecular weight of the final polymer. Chain transfer can be either introduced deliberately into a polymerization (by use of a chain transfer agent) or it may be an unavoidable side-reaction with various components of the polymerization. Chain transfer reactions occur in most forms of addition polymerization including radical polymerization, ring-opening polymerization, coordination polymerization, and cationic addition polymerization.
• Transfer to chain transfer agent. Chain transfer agents have at least one weak chemical bond, which therefore facilitates the chain transfer reaction. Common chain transfer agents includethiols, especially DDM, and halocarbons such as carbon tetrachloride. Chain transfer agents are sometimes calledmodifiers or regulators
Ans : (a)