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

Synthesis of Branched Polymers by Cationic Polymerization 17
Table 1. Multiarm star polymers and copolymers with a microgel core
Monomers Divinyl monomer Type of star Reference
IBVE 1 A n [3, 4]
p-MOS, tBOS 5 A n [5]
IB 6 A n [6–12]
IB 7 A n [7, 8]
IBVE/AcOVE 1 (A) n with
functionalized core
(AB) n
AnBn IBVE/VOEM 1 (AB) n
AnBn The synthesis of multiarm star polymers and copolymers with a microgel
core are listed in Table 1.
2.2
Synthesis Using a Multifunctional Initiator
This technique is based on the use of well-defined soluble multifunctional initiators,
which, in contrast to anionic multifunctional initiators, are readily available.
From these multiple initiating sites a predetermined number of arms can
grow simultaneously when the initiating functions are highly efficient independently
of whether the other functions have reacted or not. Under these conditions
the number of arms equals the number of initiating functions and living
polymerization leads to well defined star polymers with controlled MW and
narrow MWD. Subsequent end-functionalization and/or sequential monomer
addition can also be performed leading to a variety of end-functionalized A n or
(AB) n star-shaped structures.
2.2.1
A n-Type Star Homopolymers
2.2.1.1
Poly(vinyl ethers) n
Three arm star polymers of IBVE were synthesized by living cationic polymerization
using trifunctional initiators 8 and 9 with the same trifluoroacetate initiating
functions but different cores [19, 20]. The experimental conditions were
selected to obtain living polymerization. A series of acetic acid derivatives including
trifluoroacetic acid and the IBVE-acid adduct were found to be efficient
[17]
[13]
[18]
[14]
[18]
IB/S 6 (AB) n [15, 16]