Heteroarm H-shaped terpolymers through the combination of the diels-alder reaction and controlled/living radical polymerization techniques

Heteroarm H-shaped terpolymers (PS)(PtBA)-PEO-(PtBA)(PS) and (PS) (PtBA)-PPO-(PtBA)(PS) [where PS is polystyrene, PtBA is poly(tert-butyl acrylate), PEO is poly(ethylene oxide), and PPO is poly(propylene oxide)], containing PEO or PPO as a backbone and PS and PtBA as side arms, were prepared via the combination of the Diels-Alder reaction and atom transfer radical and nitroxide-mediated radical polymerization routes. Commercially available PEO or PPO containing bismaleimide end groups was reacted with a compound having an anthracene functionality, succinic acid anthracen-9-yl methyl ester 3-(2-bromo-2-methylpropionyloxy)-2-methyl2-[2-phenyl-2-(2,2,6, 6-tetramethylpiperidin-1-yloxy)ethoxycarbonyl]propyl ester, with a Diels-Alder reaction strategy. The obtained macroinitiator with tertiary bromide and 2,2,6,6-tetramethylpiperidin-l-oxy functional end groups was used subsequently in the atom transfer radical polymerization of tert-butyl acrylate and in the nitroxide-mediated free-radical polymerization of styrene to produce heteroarm H-shaped terpolymers with moderately low molecular weight distributions (<1.31). The polymers were characterized with ¹H NMR, ultraviolet, gel permeation chromatography,and differential scanning calorimetry.