2.2 Graft Copolymers Based on Itaconic Anhydride
and Lactic Acid
Itaconic anhydride (IAn) and lactic acid (LA) were employed as renewable starting
materials. PLA-graft copolymers were synthesized via two approaches (as shown in
Scheme 2) [43]. First, the macromonomer approach utilized IAn for Sn-catalyzed
synthesis of PLA-containing macromonomers (IAn-PLA Macro). The
BuOH
O
O
CH 3
O
O
CH 3
O O
O
R
OR'
O
BMA
O O
O
CH 3
OBu
O
Sn(Oct) 2
IAn
IAn
BMA
H
O
O
O
OH
O
O
OH
O
O
O
O
OH
O
OBu
O
CH 3
O
OBu
O
CH 3
O
OBu
O
CH 3
O
O
O
OBu
O
CH 3
CH 3
O
R
CH 3
OBu
OR'
OBu
Sn(Oct) 2
+
PLA
IAn-PLA Macro
IAn-PLA Macro +
n
m
(2)
(3)
PLA-Graft copolymer (I)
radical
(I) Macromonomer Approach
(II) Copolymer Approach
n
radical
IAn-BMA copolymer
+
(4)
(5) IAn-BMA copolymer + PLA
n
m
PLA-Graft copolymer (II)
(1)
+
Sn(Oct) 2
m
PLA
m
: R=CH 3 , R'=Bu
BA : R=H, R'=Bu
MMA : R=R'=CH 3
O
O
O
PLA-G unit
IAn unit
BMA unit
Lactide
EMA : R=CH 3 , R'=Et
Scheme 2 Synthesis of PLA-graft copolymers via two methods: (I ) macromonomer approach and
(II) copolymer approach. See text for description of reactions
146
S. Kobayashi