Chemistry Reference
In-Depth Information
num. The reflection of infrared light was reduced when the height of the
triangular aluminum gratings were reduced [15]. Al coating obtained by
roll-to-roll coating on polypropylene was polycrystalline with a grain size
20-70 nm [16].
The morphology, order, light transmittance and water vapor permeabil-
ity of the Al coated polypropylene films were reported in a previous pub-
lication [17]. The films did not transmit light in the UV and visible region
of the light spectrum and Al coating reduced the water vapor permeation
through the films [17].
The objective of this chapter is to study the absorption and reflection
of infrared light by the uncoated and Al coated surfaces of polymer films
using transmission and reflection techniques. For this purpose two com-
mercial biaxially oriented polypropylene film, a cast polypropylene film, a
milk cover and a chocolate coating material with their one surface coated
with a thin aluminum layer were examined by infrared spectroscopy. One
surface of the each film was coated with a thin aluminum layer.
1.2
EXPERIMENTAL PART
1.2.1 MATERIALS
Infrared light absorption and reflection of the uncoated and Al coated sur-
faces of polymer films were investigated and discussed in this chapter.
Two commercial biaxially oriented polypropylene samples coated with
Al by physical vapor deposition technique were examined. The samples
called commercial film 1 and commercial film 2 were provided by POLI-
NAS and POLIBAK companies, respectively. They were 16 µm and 19
µm thick and their one surface was coated with Al after a corona discharge
treatment.
An aluminum coated polypropylene film with 50-µm thickness that
was previously prepared Ozmihci et al. [17] was also examined. Al film
on polypropylene was deposited by the high vacuum magnetron sputter-
ing system having four guns. To create plasma Argon gas (99.9 wt.%) was
used. Polypropylene film fixed on glass substrates was coated by conden-
sation of Al atoms sputtered from an Al target. In the sputtering process
20 W DC power and 20 mA current were applied to pure Al target. The Al
coating obtained by magnetron sputtering method was 98-131 nm thick-
