Structure and Properties of the POSS-Containing Nanocomposites …
489
the primary beam. The recalculation of the normalized values of the scattering intensity to the punctual collimation was performed by the Schmidt method [30]. All
WAXS/SAXS measurements were performed using CuK α radiation source (λ =
0,154 nm), monochromated Ni-filter, at a temperature of 20 ± 2 °C.
2.2.7 Scanning Electron Microscopy (SEM)
Scanning electron microscopy (SEM) was performed on a JEOL JSM 6060 LA
(Tokyo, Japan) at the accelerating voltage of 30 kV and using a detector of secondary
electrons. The samples were cut into strips, before being submerged in liquid nitrogen
for 5 min and fractured as quickly as possible. Then the samples were warmed to
room temperature and fixed to an SEM stub. The fracture surface of samples was
coated with gold in vacuum to prevent accumulation of static charge and to increase
the resolution. All measurements were done at 20 °C and at magnification of ×
15000.
3 Results and Discussion
3.1 FTIR Analysis of Incorporation
of 1,2-Propanediolisobutyl-POSS into PU Matrix
A model system adduct + POSS was created by mixing of the adduct TDI-TMP and
POSS in the molar ratio NCO/OH = 1.5/1 for the FTIR study of the incorporation
of POSS into PU matrix. A similar ratio was used for the synthesis of neat PU and
POSS-containing nanocomposites. A given amount of POSS (10 wt%) was dissolved
in ethyl acetate and added to the adduct. The composition was carefully mixed and
coated on glass NaCl. The mixture was cured (and post-cured) at the 80 °C within
3 days.
In Fig. 1 the FTIR spectra of neat POSS, neat adduct, and model adduct + POSS
before curing and after curing are shown.
In the FTIR spectrum of POSS the strong absorption band at 1108 cm
−1 is
observed (Fig. 1, curve 1) which could be attributed to the asymmetric stretching
mode of ν as (Si–O–Si) in caged structure [31–33] and it is always accompanied with
the corresponding symmetric stretching counterpart mode ν s (Si–O–Si) in the spectral region from 400 to 480 cm
−1 (at 481 cm
−1 ) [31, 32, 34, 35] and corresponding
bending vibrations δ s (O–Si–O) at 565 cm
−1 [34, 35]. The band at 742 cm
−1 is
attributed to the stretching vibration in the Si–C(H 2 ) isobutyl groups of POSS [34,
36] and accompanied by CH 2 (2871 and 2926 cm
−1 ) and CH 3 (2908 and 2955 cm
−1 )
stretching [37] and corresponding deformational modes (1465, 1402, 1384, 1230,
and 839 cm
−1 ) [32, 34, 38]. The broadband at 3420 cm
−1 is attributed to the stretching
mode of ν(OH) [39].
489
the primary beam. The recalculation of the normalized values of the scattering intensity to the punctual collimation was performed by the Schmidt method [30]. All
WAXS/SAXS measurements were performed using CuK α radiation source (λ =
0,154 nm), monochromated Ni-filter, at a temperature of 20 ± 2 °C.
2.2.7 Scanning Electron Microscopy (SEM)
Scanning electron microscopy (SEM) was performed on a JEOL JSM 6060 LA
(Tokyo, Japan) at the accelerating voltage of 30 kV and using a detector of secondary
electrons. The samples were cut into strips, before being submerged in liquid nitrogen
for 5 min and fractured as quickly as possible. Then the samples were warmed to
room temperature and fixed to an SEM stub. The fracture surface of samples was
coated with gold in vacuum to prevent accumulation of static charge and to increase
the resolution. All measurements were done at 20 °C and at magnification of ×
15000.
3 Results and Discussion
3.1 FTIR Analysis of Incorporation
of 1,2-Propanediolisobutyl-POSS into PU Matrix
A model system adduct + POSS was created by mixing of the adduct TDI-TMP and
POSS in the molar ratio NCO/OH = 1.5/1 for the FTIR study of the incorporation
of POSS into PU matrix. A similar ratio was used for the synthesis of neat PU and
POSS-containing nanocomposites. A given amount of POSS (10 wt%) was dissolved
in ethyl acetate and added to the adduct. The composition was carefully mixed and
coated on glass NaCl. The mixture was cured (and post-cured) at the 80 °C within
3 days.
In Fig. 1 the FTIR spectra of neat POSS, neat adduct, and model adduct + POSS
before curing and after curing are shown.
In the FTIR spectrum of POSS the strong absorption band at 1108 cm
−1 is
observed (Fig. 1, curve 1) which could be attributed to the asymmetric stretching
mode of ν as (Si–O–Si) in caged structure [31–33] and it is always accompanied with
the corresponding symmetric stretching counterpart mode ν s (Si–O–Si) in the spectral region from 400 to 480 cm
−1 (at 481 cm
−1 ) [31, 32, 34, 35] and corresponding
bending vibrations δ s (O–Si–O) at 565 cm
−1 [34, 35]. The band at 742 cm
−1 is
attributed to the stretching vibration in the Si–C(H 2 ) isobutyl groups of POSS [34,
36] and accompanied by CH 2 (2871 and 2926 cm
−1 ) and CH 3 (2908 and 2955 cm
−1 )
stretching [37] and corresponding deformational modes (1465, 1402, 1384, 1230,
and 839 cm
−1 ) [32, 34, 38]. The broadband at 3420 cm
−1 is attributed to the stretching
mode of ν(OH) [39].