Chain transfer

Movement of the active site on one growing polymer chain to another molecule

In polymer chemistry, a chain transfer reaction is an event during a polymerization reaction by which the activity of a growing polymer chain is transferred to another molecule: P ∙ + XR ⟶ PX + R ∙ {\displaystyle {\ce {P}}^{\bullet }+{\ce {XR -> PX + R}}^{\bullet }} where • is the active center, P is the initial polymer chain, X is the end group, and R is the substituent to which the active center is transferred. 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.

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