Biomedical Engineering Reference
In-Depth Information
H
3
C
CH
3
O
O
O
O
.
+
H
C
NH
CH
H
2
C
CH
C
O
(CH
2
)
6
O
C
CH
H
2
C
CH
NH
H
2
N
N
n
H
3
C
CH
3
C
O
H
H
3
C
H
3
C
CH
3
CH
3
O
O
OH
O
O
C
C
H
C
NH
CH
H
2
C
CH
C
O
(CH
2
)
6
O
C
CH
H
2
C
CH
NH
O
NH
n
H
3
C
H
3
C
CH
3
CH
3
CH
3
H
3
C
H
3
C
CH
3
N
O
.
Scheme 5.10
Covalent attachment of 4 - amino - TEMPO to epoxy - PEA.
5.2.4
Properties of AABBP s
5.2.4.1
MWs, Thermal, Mechanical Properties, and Solubility
All the AABBPs obtained via AP [14] have high molecular weights (
M
w
=
24,000 -
180,000 Da, GPC) and narrow polydispersity (1.20-1.81).
DSC study of AABBPs showed that these polymers have a wide range of glass
transition temperature (
T
g
from 5 ° C to 102 °C), some of them (PEAs and PEUs)
are semicrystalline with
T
m
103 - 153 ° C [14, 53] . It was shown that
T
g
of the poly-
mers can be increased by incorporating rigid fragments into macrochains such
are dianhydrohexitols [25, 26] or aromatic diacid - 1,3 - bis(4 - carboxyphenoxy)propane
[61] .
The chemical structure affects the mechanical properties of AABBPs, which
varies in a wide range: tensile strength from 15-20 (PEURs and some PEAs) to
80-100 MPa (PEUs and some PEAs), elongation at break from 8-100 (PEUs and
some PEAs) to 800-1000% (PEURs and some PEAs), Young's modulus up to
2 - 6 GPa (PEUs and some PEAs).
The AABBPs are soluble in common organic solvents such as DMF, THF,
methylene chloride, chloroform, some of them in dioxane, acetone, and ethanol.
The low melting temperatures and solubility of AABBPs in common solvents
substantially facilitate their processing into different shapes.
=
5.2.4.2
Biodegradation of AABBP s
Katsarava, Chu
et al.
studied
in vitro
biodegradation of AABBPs under the con-
ditions close to physiological (
t
=
37 ° C and pH 7.4) using both potentiometric
