142 Advances in Polymer Science Editorial Board: A. Abe. A.-C ...

84 N. Hadjichristidis, S. Pispas, M. Pitsikalis, H. Iatrou, C. Vlahos
Scheme 8
Scheme 9
Living polymer chains were reacted with bromomethyl naphthalene but a
fairly large amount of the coupled byproduct was formed. The byproduct was
minimized to 5–10% by using the Grignard reagent, leading to the formation of
A 2 B stars. The final polymer was contaminated by the starting homopolymers
and traces of PEO homopolymer. Polydispersity indices as high as 1.2–1.3 were
obtained with this procedure.
A special technique was employed by Naka et al. for the preparation of A 2 B
stars, A being PEO and B polyoxazoline (POX) [26] according to Scheme 8. Ru(III)
complexes with bipyridyl terminated polymers were utilized in this method.
Characterization data were not provided for these miktoarm star copolymers.
The chlorosilane method was adopted for the synthesis of miktoarm stars of
the type B(A-b-B) 2 where A is PI and B is PS [27]. The synthetic procedure was
similar to that used for the preparation of A 2B stars except that two of the arms
are diblock copolymers, as shown in Scheme 9. Extensive characterization data
were given to confirm the synthesis of well defined copolymers.