Generally, the greater the polymer's cohesive energy density, the more difficult it is to open the polymer molecular chain and the smaller the amount of penetration. The free volume free volume is the porosity between the molecules of the polymer, and the reduction of the free volume can correspondingly increase the barrier property of the material. If a plasticizer is added during processing, it will result in a low glass transition temperature of the polymer, an increase in free volume, and a corresponding material barrier. Crystallinity crystallinity reflects the regularity and flexibility of the polymer compound chain, and the symmetry of the substituent. As the crystallinity increases, the water permeability and oxygen permeability become smaller.
At high temperatures, the barrier properties of nylon will be better than that of the polymer material. The barrier property of the polymer material is less affected by the humidity than the temperature. As the humidity increases, the barrier property of the plastic decreases, and its barrier property to humidity. Human sensitivity is different, the order is as follows, nylon, moisture sensitive barrier materials are not suitable for very humid packaging or application environments, such as liquid, cooked food and other packaging.
It can be seen from the above factors that in high barrier polymer materials, nylon is sensitive to temperature and humidity and is not affected by the environment. The first phase of the plastic packaging is transparent and transparent. The transparency is good. The application of some barrier polymer materials is good for oxygen barrier. The composite film is often used in fresh food packaging materials such as sausage and milk. Packaging such as juice, non-food volume such as solvent, pharmaceutical packaging, etc.
The application of the copolymer can be specifically used for moisture-proof packaging such as various dry foods, dried vegetables, milk powder, tea leaves and the like. The application of nylon is mainly used in the form of blended bottles for the barrier packaging of wine, beverages, pharmaceuticals and food. The copolymer used is generally not used for beverage packaging, and is mainly used for seasoning, dry soup powder, chocolate, and the like. Applications can be used for food and pharmaceutical packaging, including beer, milk, soda, etc. The first batch of beer bottles appeared in European and Italian companies, and the one-month taste was the same as that of the glass bottles. The application is mainly used for the packaging of carbonated beverages.
In short, the barrier properties of polymer materials are not static. Through appropriate modification methods, such as blending, compounding, filling and other high-barrier polymer materials, nylon is sensitive to temperature and humidity, and is not affected by the environment. influences. The first phase of the plastic packaging is transparent and transparent, and the transparency is good. The application of some barrier polymer materials is good for oxygen barrier, and the composite membrane method can improve the barrier properties to varying degrees.
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