Confined Glassy Dynamics in a Star-Shaped Polymer …
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2.4 Fourier-Transform Infrared Spectroscopy (FTIR)
Fourier transform infrared spectroscopy (FTIR) measurements were performed with
a Bio–Rad FTS 6000 FTIR spectrometer equipped with a UMA 500 IR microscope
and a liquid nitrogen-cooled mercury-cadmium telluride (MCT) detector (Kolmar
Technologies, Inc., USA). To control the sample temperature, a THMS 350 V stage
(Linkam Scientific Instruments, UK) has been used and continuously flushed with
dry nitrogen during the measurement. To monitor the sample during crystallization,
spectra were recorded with an initial time resolution of approximately 2 min which
was increased to about 5 min after 2 h of crystallization.
The sample material has been deposited by drop-casting from toluene solution
(20 mg/ml) onto an IR-transparent substrate (BaF2, Korth Kristalle GmbH, Germany)
until the desired sample thickness and, thus, absorption was reached. Then, the sample
was dried under ultra-high vacuum (10
–5 mbar) at 423 K for 20 h before the actual
measurement.
2.5 Differential Scanning Calorimetry (DSC)
The differential scanning calorimetry (DSC) measurements were conducted with
a Q2000 differential scanning calorimeter (TA Instruments) in a temperature range
from 335 to 515 K. Sample masses of 5–10 mg were put into standard aluminum pans
and studied at a heating rate of 10 K/min. From the area underneath the melting peak
the specific heat of fusion H f was extracted to calculate the degree of crystallinity
f c according to [18]:
f c =
H f
H f,c
(1)
where H f,c = 86.5864 J/g [18, 19] denotes the specific heat of fusion of iPS with
100% crystallinity.
3 Experimental Results
3.1 Crystallite Dimensionality
Classically, crystallization is monitored by calorimetric techniques. Also, the heat
capacity of POSS-iPS as determined by means of DSC exhibits a sharp melting peak
if the material was crystalized before (Fig. 1a). The area under this peak is used to
271
2.4 Fourier-Transform Infrared Spectroscopy (FTIR)
Fourier transform infrared spectroscopy (FTIR) measurements were performed with
a Bio–Rad FTS 6000 FTIR spectrometer equipped with a UMA 500 IR microscope
and a liquid nitrogen-cooled mercury-cadmium telluride (MCT) detector (Kolmar
Technologies, Inc., USA). To control the sample temperature, a THMS 350 V stage
(Linkam Scientific Instruments, UK) has been used and continuously flushed with
dry nitrogen during the measurement. To monitor the sample during crystallization,
spectra were recorded with an initial time resolution of approximately 2 min which
was increased to about 5 min after 2 h of crystallization.
The sample material has been deposited by drop-casting from toluene solution
(20 mg/ml) onto an IR-transparent substrate (BaF2, Korth Kristalle GmbH, Germany)
until the desired sample thickness and, thus, absorption was reached. Then, the sample
was dried under ultra-high vacuum (10
–5 mbar) at 423 K for 20 h before the actual
measurement.
2.5 Differential Scanning Calorimetry (DSC)
The differential scanning calorimetry (DSC) measurements were conducted with
a Q2000 differential scanning calorimeter (TA Instruments) in a temperature range
from 335 to 515 K. Sample masses of 5–10 mg were put into standard aluminum pans
and studied at a heating rate of 10 K/min. From the area underneath the melting peak
the specific heat of fusion H f was extracted to calculate the degree of crystallinity
f c according to [18]:
f c =
H f
H f,c
(1)
where H f,c = 86.5864 J/g [18, 19] denotes the specific heat of fusion of iPS with
100% crystallinity.
3 Experimental Results
3.1 Crystallite Dimensionality
Classically, crystallization is monitored by calorimetric techniques. Also, the heat
capacity of POSS-iPS as determined by means of DSC exhibits a sharp melting peak
if the material was crystalized before (Fig. 1a). The area under this peak is used to