Chemistry Reference
In-Depth Information
The chocolate packing had an outer layer coated with aluminum. The
inner layer was Milk cover had the function of opening the packing when
it was pulled. The inner side of the cover, which was in contact with the
milk, was covered with a polymer layer.
FIGURE 1.5
The SEM micrographs Al coated surface of (a) the chocolate packing; (b)
milk cover.
Photographs of chocolate packing and milk cover are shown in Fig.
1.4. The SEM micrographs of their Al coated surfaces are in Fig. 1.5. They
have an even Al coating as seen in Fig. 1.5.
1.3.2
TRANSMISSION SPECTRA OF AL COATED
POLYPROPYLENE FILMS
1.3.2.1. COMMERCIAL AL COATED POLYPROPYLENE FILMS
The transmission infrared spectra of commercial film 1 and 2 were ob-
tained by placing the films in the path of the infrared light. Spectrum 1
and spectrum 2 in Fig. 1.6 belonged to commercial film 1 and film 2, re-
spectively. The base line absorbance values were close to 1for commercial
film 1 and to 4 for commercial film 2.This is that indicated 1/10,000 and
1/10 of the input infrared light was transmitted from the samples. The Al
coating on the film acted as a barrier to infrared light. The higher coating
thickness of commercial film 2 (185 nm) than that of commercial film 1
(30 nm) resulted higher level of shielding from infrared radiation. The film
2 had better infrared light shielding efficiency than the film 1.
