|
Chemical
Properties
of
Selected
Polymers
:
A
chart
of
the
chemical
properties
for
some
of
our
most
used
polymers:
|
Polymer
Type
|
Inherent
Viscosity
(dL/g)
|
Melting
Point
(°C)
|
Glass
Transition
Temperature
(°C)
|
Solubility
*
|
|
50/50
DL-PLG
|
0.55
-
0.75
|
Amorphous
|
45
-
50
|
1,2,3,4,5,6
|
|
65/35
DL-PLG
|
0.55
-
0.75
|
Amorphous
|
45
-
50
|
1,2,3,4,5,6
|
|
75/25
DL-PLG
|
0.55
-
0.75
|
Amorphous
|
50
-
55
|
1,2,3,4,5,6
|
|
85/15
DL-PLG
|
0.55
-
0.75
|
Amorphous
|
50
-
55
|
1,2,3,4,5,6
|
|
DL-PLA
|
0.55
-
0.75
|
Amorphous
|
55
-
60
|
1,2,3,4,5,6
|
|
L-PLA
|
0.90
-
1.2
|
173-178
|
60
-
65
|
1,4,5
|
|
PCL
|
1.0
-
1.3
|
58-63
|
-65
-
-60
|
1,4,5,6
|
*
Solvents
(partial
listing
only):
| |
1=
methylene
chloride |
| |
2=
tetrahydrofuran |
| |
3=
ethyl
acetate |
| |
4=
chloroform |
| |
5=
hexafluoroisopropanol |
| |
6=
acetone |
Physical
Properties
of
Selected
Polymers
:
A
chart
of
the
physical
properties
for
some
of
our
most-used
polymers.
|
Polymer
Type
|
Specific
Gravity(g/ml)
|
Tensile
Strength
(psi)
|
Elongation
(%)
|
Modulus
(psi)
|
|
50/50
DL-PLG
|
1.34
|
6000
-
8000
|
3
-
10
|
2
-
4
x
105
|
|
65/35
DL-PLG
|
1.30
|
6000
-
8000
|
3
-
10
|
2
-
4
x
105
|
|
75/25
DL-PLG
|
1.30
|
6000
-
8000
|
3
-
10
|
2
-
4
x
105
|
|
85/15
DL-PLG
|
1.27
|
6000
-
8000
|
3
-
10
|
2
-
4
x
105
|
|
DL-PLA
|
1.25
|
4000
-
6000
|
3
-
10
|
2
-
4
x
105
|
|
L-PLA
|
1.24
|
8000
-
12000
|
5
-
10
|
4
-
6
x
105
|
|
PCL
|
1.11
|
3000
-
5000
|
300
-
500
|
3
-
5
x
104
|
DL-PLG
poly(DL-lactide-co-glycolide)
DL-PLA
poly(DL-lactide)
L-PLA
poly(L-lactide)
PCL
poly(
e-caprolactone)
Biodegradation
information
:
Hydrolysis
is
the
principal
mode
of
degradation
for
glycolide,
lactide
and
e-caprolactone
polymers
and
copolymers.
Degradation
proceeds
first
by
diffusion
of
water
into
the
material
(initially
into
the
more
amorphous
zones);
followed
by
random
hydrolysis;
fragmentation
of
the
material;
and
finally
a
more
extensive
hydrolysis
accompanied
by
phagocytosis,
diffusion
and
metabolism.
The
hydrolysis
is
affected
by
the
size
and
hydrophilicity
of
the
particular
polymer
implant,
the
crystallinity
of
the
polymer
and
the
pH
and
temperature
of
the
environment.
In
general,
the
degradation
time
will
be
shorter
for
low-molecular-weight
polymers,
more
hydrophilic
polymers,
more
amorphous
polymers
and
copolymers
higher
in
glycolide.
Therefore,
at
identical
conditions,
low-molecular-weight
copolymers
of
dl-lactide
and
glycolide,
such
as
50/50
DL-PLG,
will
degrade
relatively
rapidly,
whereas
the
high-molecular-weight
homopolymers
L-PLA
and
PCL
will
degrade
much
more
slowly.
Birmingham
Polymers
can
often
tailor
polymers
to
meet
specific
degradation
time
requirements
through
copolymerization,
molecular
weight
and
end-group
selection.
Once
hydrolyzed,
the
products
of
hydrolysis
are
either
metabolized
or
excreted.
The
lactic
acid
generated
by
the
hydrolytic
degradation
of
PLA
becomes
incorporated
into
the
tricarboxylic
acid
cycle
and
is
excreted
as
carbon
dioxide
and
water.
Structure
of
LACTEL®
Lactide/Glycolide
Copolymers
|
