38
K. Adrjanowicz
To describe the crystallization kinetics of PC at atmospheric pressure we have also
performed time-dependent studies carried out at few temperatures located within
T g and T m . Obtained temperature evolution of the overall crystallization time is
presented in Fig. 8a. Its maximum forms a characteristic ‘nose’ on the TTT diagram.
When decreasing the temperature of the melt, crystallization can be avoided when the
cooling line does not intersect with the crystallization zone. For PC, such a critical
cooling rate is 1 K/min.
In analogy to TTT diagram, crystallization tendency of glass-forming systems can
be also analyzed in terms of Continuous-Heating-Transformation diagrams (CHT)
2.6 MPa/min
5.8 MPa/min
10 MPa/min
21 MPa/min
32 MPa/min
44.5 MPa/min
55 MPa/min
67.7 MPa/min
isotherm T=243 K
10
0
10
1
10
2
10
3
10
4
10
5
0
400
800
1200
10
0
10
1
10
2
10
3
10
4
10
5
0
400
800
1200
10
0
10
1
10
2
10
3
10
4
10
5
10
6
160
180
200
220
240
10
0
10
1
10
2
10
3
10
4
10
5
10
6
160
180
200
220
240
LIQUID
GLASS
CDT diagram
(c)
67.7 MPa/min
p (MPa)
time (s)
2.6 MPa/min
TPT diagram
CRYSTAL
(a)
(b)
(d)
GLASS
CRYSTAL
24.3 MPa/min
35.7MPa/min
47 MPa/min
59.8 MPa/min
69.7 MPa/min
154 MPa/min
isotherm T=243 K
p (MPa)
time (s)
2
4
.3
M
P
a
/m
in
LIQUID
5 .8 M
P a /m
in
1 5 4 M
P a /m
in
UNDERCOOLED
LIQUID
T m
GLASS
LIQUID
TTT diagram
0.1 K/min
0.1 K/min
0.2 K/min
0.5 K/min
2.0 K/min
5.0 K/min
t cryst
T (K)
time (s)
5 K/min
CHT diagram
CRYSTAL
50 K/ mi n
10 K/ mi n
GLASS
UNDERCOOLED
LIQUID
LIQUID
CRYSTAL
5 K/min
0.1 K/min
5 K/min
2 K/min
0.5 K/min
0.2 K/min
0.1 K/min
t cryst (TTT)
t cryst (CHT)
T (K)
time (s)
T m
Fig. 8 a TTT diagram demonstrating crystallization tendency of PC at atmospheric pressure upon
lowering the temperature with different cooling rates. The crystallization data were collected upon
time-dependent studies carried out at a few different temperatures. In each case, the experimental
protocol involved cooling the liquid from T > T m to the desired crystallization temperature (T <
T m ); b CHT diagram demonstrating crystallization tendency of PC at 0.1 MPa upon reheating of
the glassy sample with different heating rates. The maxima of the overall crystallization determined
based on experimental data for cooling and heating scenarios are presented as orange square and
star symbols, respectively; c TPT diagram demonstrating crystallization tendency of PC upon
compression at 243 K with different scanning rates. The crystallization data were collected upon
time-dependent studies carried out at few different pressures along isotherm T = 243 K. In each case
the experimental protocol involved compression of the liquid at 243 K from atmospheric pressure
to a desired crystallization pressure; d CDT diagram demonstrating crystallization tendency of
PC at 243 K upon decompression carried out with different rates. Star symbols demonstrate the
nose of the crystallization curve constructed using dielectric results collected upon decompression
experiments, while solid symbols refer to crystallization data collected for the pressured sample.
Adapted with permission from [61]. Copyright (2018) American Chemical Society
K. Adrjanowicz
To describe the crystallization kinetics of PC at atmospheric pressure we have also
performed time-dependent studies carried out at few temperatures located within
T g and T m . Obtained temperature evolution of the overall crystallization time is
presented in Fig. 8a. Its maximum forms a characteristic ‘nose’ on the TTT diagram.
When decreasing the temperature of the melt, crystallization can be avoided when the
cooling line does not intersect with the crystallization zone. For PC, such a critical
cooling rate is 1 K/min.
In analogy to TTT diagram, crystallization tendency of glass-forming systems can
be also analyzed in terms of Continuous-Heating-Transformation diagrams (CHT)
2.6 MPa/min
5.8 MPa/min
10 MPa/min
21 MPa/min
32 MPa/min
44.5 MPa/min
55 MPa/min
67.7 MPa/min
isotherm T=243 K
10
0
10
1
10
2
10
3
10
4
10
5
0
400
800
1200
10
0
10
1
10
2
10
3
10
4
10
5
0
400
800
1200
10
0
10
1
10
2
10
3
10
4
10
5
10
6
160
180
200
220
240
10
0
10
1
10
2
10
3
10
4
10
5
10
6
160
180
200
220
240
LIQUID
GLASS
CDT diagram
(c)
67.7 MPa/min
p (MPa)
time (s)
2.6 MPa/min
TPT diagram
CRYSTAL
(a)
(b)
(d)
GLASS
CRYSTAL
24.3 MPa/min
35.7MPa/min
47 MPa/min
59.8 MPa/min
69.7 MPa/min
154 MPa/min
isotherm T=243 K
p (MPa)
time (s)
2
4
.3
M
P
a
/m
in
LIQUID
5 .8 M
P a /m
in
1 5 4 M
P a /m
in
UNDERCOOLED
LIQUID
T m
GLASS
LIQUID
TTT diagram
0.1 K/min
0.1 K/min
0.2 K/min
0.5 K/min
2.0 K/min
5.0 K/min
t cryst
T (K)
time (s)
5 K/min
CHT diagram
CRYSTAL
50 K/ mi n
10 K/ mi n
GLASS
UNDERCOOLED
LIQUID
LIQUID
CRYSTAL
5 K/min
0.1 K/min
5 K/min
2 K/min
0.5 K/min
0.2 K/min
0.1 K/min
t cryst (TTT)
t cryst (CHT)
T (K)
time (s)
T m
Fig. 8 a TTT diagram demonstrating crystallization tendency of PC at atmospheric pressure upon
lowering the temperature with different cooling rates. The crystallization data were collected upon
time-dependent studies carried out at a few different temperatures. In each case, the experimental
protocol involved cooling the liquid from T > T m to the desired crystallization temperature (T <
T m ); b CHT diagram demonstrating crystallization tendency of PC at 0.1 MPa upon reheating of
the glassy sample with different heating rates. The maxima of the overall crystallization determined
based on experimental data for cooling and heating scenarios are presented as orange square and
star symbols, respectively; c TPT diagram demonstrating crystallization tendency of PC upon
compression at 243 K with different scanning rates. The crystallization data were collected upon
time-dependent studies carried out at few different pressures along isotherm T = 243 K. In each case
the experimental protocol involved compression of the liquid at 243 K from atmospheric pressure
to a desired crystallization pressure; d CDT diagram demonstrating crystallization tendency of
PC at 243 K upon decompression carried out with different rates. Star symbols demonstrate the
nose of the crystallization curve constructed using dielectric results collected upon decompression
experiments, while solid symbols refer to crystallization data collected for the pressured sample.
Adapted with permission from [61]. Copyright (2018) American Chemical Society