In daily life, people are exposed to more plastic bags (film), generally polyvinyl chloride (PVC) and polyethylene (PE) plastic film (bag), how to distinguish them, the following summarizes several simple methods :
(1) Touch method
It feels lubricated by hand, and the surface is coated with a layer of wax (chemically called waxy), which is a non-toxic polyethylene film bag, while the polyvinyl chloride film is somewhat sticky to the touch.
(2) dithering method
The hand is shaken, the sound is brittle, and the quality is easy to float is a polyethylene film bag. The low-pitched sound is a polyvinyl chloride film bag.
(3) Combustion method
It is flammable in case of fire, the flame is yellow, there is paraffin-like oil dripping when burning, and there is a gas when the candle burns. It is a non-toxic polyethylene film bag. If it is not easy to burn, it will be extinguished when it leaves the fire. The flame is green and it is a PVC film bag.
(4) Water immersion method
After immersing the plastic bag in water and pressing it into the water, the polyethylene that can float out of the water surface is polyvinyl chloride (the density of polyethylene is less than water, and the density of polyvinyl chloride is greater than water; respectively, at room temperature is about 0.92 g/cm3 and 1.4 g/cm3).
Alternatively, a copper wire may be taken, fired red in a fire, and then the copper wire is brought into contact with the test plastic film to cause a chemical change, and the copper wire with the plastic component is returned to the flame. At this time, it is necessary to observe carefully. If there is a colorful and dazzling green flame, it means that the plastic material contains chlorine and belongs to the polyvinyl chloride material.

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