Biomedical Engineering Reference
In-Depth Information
CH
3
O
O
OH
HO
O
CH
3
O
n
(a)
O
OH
OH
HO
HO
CH
3
O
(b)
1.28
(a) Structure and (b) degradation products (fumaric acid and
propylene glycol) of poly(propylene fumarate).
O
O
HO
O
H
a
b
c
1.29
Poloxamers structure.
O
O
O
(a)
O
*
O
O
*
n
(b)
O
O
O
O
O
O
O
*
*
p
n
m
CH
3
O
(c)
1.30
(a)
p
-Dioxanone, (b) PPDO and (c) poly(
p
-dioxanone-co-
l
-lactide).
1997); the ether bond provides both hydrophilicity and flexibility (Fig. 1.30). It
is prepared with rOP of
p
-dioxanone. The main unit contains one ether bond,
one ester bond and no side chains. PPDO degradation results from hydrolysis
which follows a mechanism similar to that of aliphatic polyesters, even if
in these materials hydrophilicity is more marked because of the presence of
ether bonds. PPDO is mainly used for bioresorbable suture threads because
of its good tensile strength (nishida, 2005, lanza
et al.
, 2007). Moreover,
copolymers such as poly(
p
-dioxanone-co-
l
-lactide) have been synthesized.
Polyvinyl alcohol (PVa) is a polyhydroxy polymer, produced by the
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