Abstract:
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We describe the synthesis of diblock and triblock copolymers by sequential
atom transfer radical polymerization of styrene and acetoxymethylstyrene. Contrary to
the usual block copolymerization involving isolation of the macroinitiator, a convenient
one-pot procedure is developed. This is possible because of the preferential polymerization
of acetoxymethylstyrene, even in the presence of residual styrene, as inferred
from characterization of the intermediate polystyrenes and the block copolymers by size
exclusion chromatography, 1H NMR, Fourier transform infrared spectroscopy, differential
scanning calorimetry, and GPEC techniques. The latent acetoxy functionalities
in these block copolymers are shown to be easily unmasked to OOH and OBr functionalities,
with the potential for block ionomers and dense graft architectures. |