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

30 B. Charleux, R. Faust
Table 2. Multiarm star polymers and copolymers synthesized using a multifunctional initiator
Monomers Multi-functional initiatorType of star Reference
IBVE 8, 9 A 3 [19, 20]
10 A 4 [21, 22]
p-MOS 11, 12 A 3 [23]
S 13 A 6 [24, 25]
IB 14–17 A 3 [26–34]
18 A 4 [35]
19 A 6 [36]
20, 21 A 8 [37]
IBVE/AcOVE 8 (AB) 3 [38]
IB/S 14, 15 (AB) 3 [39, 40]
20, 21 (AB) 8 [41]
IB/p-MeS 14 (AB) 3 [42]
IB/THF 14 (AB) 3 [43]
IB/MMA 14 (AB) 3 [44]
polymerization of IB using a trifunctional initiator (tricumyl chloride, 14), and
the living ends were quantitatively capped with 1,1-diphenylethylene. The product
obtained upon quenching with methanol was isolated, redissolved in THF,
and quantitatively metallated with K/Na alloy. The reaction mixture was filtered
and excess LiCl was added to replace K + with Li + , which gives a PIB macroinitiator
suitable for anionic polymerization of MMA. The polymerization of MMA
was carried out in THF/n-hexane (70/30 v/v) solvent mixture to ensure solubility
of PIB at –78 °C. A series of star block copolymers with 27–46% MMA has
been prepared with low polydispersity (M w /M n 2) identical nucleophilic
functions sufficiently separated in space to avoid steric hindrance, may be used
to link together similar living macromolecular chains. Well defined star structures
are obtained when these nucleophilic functions add cleanly and efficiently
to the living ends without any side reaction. It is necessary to use strictly stoichiometric
concentrations of the chain ends and of the nucleophilic functions to
achieve the target structure and to avoid purification.