Identification by combustion identification method:
1. PP is easy to burn, melts and drips, and the burning flame state is that the upper yellow and lower blue smoke are less, and it continues to burn after leaving the fire, and it smells of oil.
2. PVC is difficult to burn, melts and softens, and the burning flame state is yellow on top and green on the bottom with smoke, extinguished from fire, and pungent and sour.
3.
PP sheet is a thermoplastic resin obtained by polymerizing propylene. There are three configurations of isotactic, random and syndiotactic, and industrial products are mainly composed of isotactic. Polypropylene also includes copolymers of propylene with small amounts of ethylene. Usually translucent colorless solid, odorless and nontoxic. Due to the regular structure and high crystallization, the melting point is as high as 167 ℃, heat resistance, and the products can be sterilized by steam. With a density of 0.90g/cm3, it is the lightest general-purpose plastic. Corrosion resistance, tensile strength 30MPa, strength, rigidity and transparency are better than polyethylene. The disadvantage is that it has poor low temperature impact resistance and is easy to age, but it can be overcome by modification and addition of antioxidants respectively.
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