End-Functional Poly(<i>tert</i>-butyl acrylate) Star Polymers by Controlled Radical Polymerization

Star-shaped poly(tert-butyl acrylate) (PtBA) was prepared by an “arm first” method using copper-mediated atom transfer radical polymerization (ATRP). Divinylbenzene, 1,4-butanediol diacrylate, and ethylene glycol dimethacrylate were employed as the coupling reagents. PtBA star polymers were successfully prepared using preformed PtBA macroinitiators. Several factors pertinent to star polymer formation, including the choice of exchange halogen and solvent, the addition of copper(II) species, the ratio of coupling reagent to macroinitiator, and the reaction time for the star formation, were addressed. Functional initiators were introduced to directly prepare arms with α-functionalities since ATRP is highly tolerant to functional groups. End-functional star polymers with various functionalities, such as hydroxy, epoxy, amino, cyano, and bromine, on the outer layers were successfully synthesized.