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The density, transparency and absorbency of food packages

Categories: Company NewsRelease time: 2018-09-20 17:44:00 RSS subscription Font size:【 Large Middle Small

In addition to mechanical properties, thermal properties, permeability and chemical properties, there are also density and transparency.

1. Food packaging bag density
The density of food packages is a function of the quantity of individual molecules per unit volume and the way they are stacked. Recreational hydrogen compounds are composed of light atoms and, therefore, generally have a lower density. The density of polyethylene, polypropylene, and polystyrene for simple hydrocarbons is 0.9. 丨. Ig/cm3. If you transfer hydrogen to a heavier atom like fluorine or chlorine, you get a density of 1.2. Right? 丨. 5 g/cm3 polyvinyl chloride material and density of 2.1 ~ 2.28/0 ^ ptfe. The density of pom is higher because the c-0 - C bond is packed more tightly.
Crystalline polymers are always denser than amorphous polymers because they are more densely packed and denser. The density can reflect the composition, structure and crystallinity of the polymer.
2. Transparency of food package
The transparency of food package is the ratio of the optical penetration M through the object to the total optical penetration house: the ratio, also known as the transmittance, is sometimes measured with a certain wavelength range of light.
Density difference is electrical to determine transparency because the refractive index is always proportional to the density
Department. If the density of amorphous and crystalline materials, when light through the two kinds of structure of mixed ^ when slightly scattering, and the material is transparent; On the other hand, if the density of the two are very different material is opaque. For example, in polyethylene, the density difference is large (the relative density of amorphous state is 0. 8 and the crystalline state is 0. Therefore, in the case of obvious crystallization, the material is opaque. The '
Small density of propylene (amorphous of relative density is 0.85, and the crystalline state is bound. 94 >, ^ & ^
However, if the polymer crystal material is rapidly cooled, the resulting crystal is so tiny that it has a shorter wavelength than the light that is passing through it, the polymer crystal material can be transparent.
3. Food packaging bags are absorbent
The food packaging bag will measure the weight in distilled water for 24h at a certain temperature (25 zhangs or 20: t 2 zhangs) of the tested sample with the specified size. Also available water quantity per unit area (10 ^ / 112 or # 100 ^ 112) or water weight (mg) table no.

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