Well‐defined polyoxazoline‐based alkoxyamines as efficient macroinitiators in nitroxide‐mediated radical polymerization of styrene

Abstract

Abstract The synthesis of two well‐defined 2,2,5‐trimethyl‐4‐phenyl‐3‐azahexane‐3‐nitroxide‐terminated poly(2‐methyl‐2‐oxazoline) with narrow dispersity ( M w / M n = 1.1) has been achieved for the first time. The insertion of the alkoxyamine end groups at one or both ends of poly(2‐methyl‐2‐oxazoline) (PMEOX) chains has been successfully done using a method based on “terminating reagent method.” These macroinitiators have molecular weights ranging from 6.3 × 10 3 to 9.4 × 10 3 g mol −1 . In contrast, attempt to introduce the alkoxyamine group at one end of PMEOX chain through the “initiator method” has furnished a mixture of alkoxyamine‐graft polyoxazolines because of rearrangement of alkoxyamine occurring during the synthesis of PMEOX. The macroinitiators obtained by terminating reagent method have been used successfully for polymerization of styrene by nitroxide‐mediated radical polymerization (NMP), which exhibited all the expected features of a controlled system. The control of NMP has been proved by a good agreement between theoretical and experimental molecular weights and by narrow dispersity ( M w / M n < 1.2). Different types of well‐defined multiblock copolymers have been prepared: diblock copolymers poly[(2‐methyl‐2‐oxazoline)‐ b ‐(styrene)] (PMEOX‐ b ‐PS) and, for the first time, triblock copolymers poly[(styrene)‐ b ‐(2‐methyl‐2‐oxazoline)‐ b ‐(styrene)] (PS‐ b ‐PMEOX‐ b ‐PS). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.