How to distinguish cellophane, polyester and polyethylene

How to distinguish cellophane, polyester and polyethylene

• Externally, cellophane and polyester (for example, polyester) materials in the form of films are quite similar - very transparent, colorless, tough enough - they “crunch” when crushed. At present, the bulk of transparent film packaging material is polyester, polypropylene and polyethylene, and only a small part is other polymeric materials, including cellophane. It is easy to distinguish them - with an equal thickness, a lavsan film is much stronger than cellophane. In addition, cellophane plasticizes glycerol, which makes it have a sweetish taste - unlike completely insoluble and more inert lavsan and polyethylene.
• Polypropylene films, It is similar to polyester films, The only difference is the density is lighter than polyester. 
• Polyethylene films, unlike cellophane and lavsan films, are less transparent (the thicker the film, the more turbid the view of the lumen), do not crunch when crushed (this is true only for low-density polyethylene, high-density polyethylene crunches), much more plastic (when stretching is not restore the original form).
• Cellophane films are very tear resistant. However (unlike lavsan and polyethylene), starting to tear from the edge, they tear on with little or no effort (the effect of a zipper). This property reduces the scope of cellophane as a packaging material.
• Cellophane, unlike other polymeric packaging materials, does not melt when ignited.