Biomedical Engineering Reference
In-Depth Information
OH
OEt
O
HO
Py, HOTs
O
+
Toluene
O
OH
OEt
O
HO
O
O
O
O
O
O
KOtBu
H
2
NCH
2
CH
2
NH
2
O
O
O
O
O
O
Scheme 4.14
Synthesis of di(5 - methyl - 2 - ethylidene[1.3]dioxan - 5yl)methyl ether.
O
O
O
+
HOCH
2
CH
2
OH
O
O
O
O
O
O
OCH
2
CH
2
n
T
g
= 115 °C
O
O
+
HOCH
2
CH
2
OH
O
O
O
O
O
O
O
O
O
OCH
2
CH
2
n
T
g
= 319 °C
Scheme 4.15
Glass transition temperatures for polymers prepared from DETOSU and
di(5 - methyl - 2 - ethylidene[1.3]dioxan - 5yl)methyl ether, each with
trans
- CDM.
diketene acetal. Since glass transition temperatures are a direct indication of chain
fl exibility, it is clear that polymers prepared using the alternate diketene acetal
are signifi cantly more fl exible and that use of the alternate diketene acetal should
produce useful materials at higher molecular weight than those based on
DETOSU.
