Chemistry Reference
In-Depth Information
The peaks observed at 3000-2800 cm
-1
belonged to C-H asymmetric
and symmetric stretching, at 1450 cm
-1
C-H bending, at 1350 cm
-1
C-H
deformation bending [17]. The peak at 973 cm
-1
belongs to amorphous
CH
3
rocking and C-C chain stretching vibrations and the peak at 998 cm
-1
belongs to crystalline CH
3
rocking, CH
2
wagging and CH bending vibra-
tions [20].
The magnetron sputtered film's polymer layer and Al layer were 50
µm and 185 nm, respectively. This film was nearly three times thicker
than commercial film 1 and commercial film 2. The absorbance values of
this film in transmission mode were too high, since both the Al layer and
polypropylene layer were thicker. The FTIR transmission spectrum of this
thick film coated by magnetron sputtering had very high absorbance val-
ues indicating it was also a good shield for infrared radiation.
1.3.3
SPECULAR REFLECTANCE OF SPECTRA OF THE FILMS
1.3.3.1
COMMERCIAL AL COATED POLYPROPYLENE FILM 1
Figure 1.6 shows the specular reflectance spectra of Al coated and uncoat-
ed surfaces of the film 1. Al coated surface reflected 100% of the infrared
rays since the absorbance values were very close to zero. Uncoated surface
had the characteristic spectrum of polypropylene. However, there were
other peaks observed called fringes due to reflection of light from both
surfaces of the thin film.
FIGURE 1.6
Transmittance spectra of the commercial film 1 and 2.
