We have a lot of plastics in our daily life. Many things are made of plastic, but we also know that there are many kinds of plastics, but how should we identify so many materials?
First, the appearance identification method
(1) PE, PP, PA, etc. have different bendability, the hand touches with a hard waxy slip, and there is a soft horny sound when struck. Compared with PS, ABS, PC, PMMA, etc., there is no extensibility, the hand touch is sexy, and the sound is crisp when tapping.
(2) The relative density of PE and PP is less than 1, so it floats on water; most other plastics are larger than 1, so they sink in water.
(3) Before the dyeing, the LDPE plastic particles are milky white and transparent, soft, soft and tough, slightly stretchable, and easy to bite and deform with teeth. HDPE is milky white, opaque, slightly hard texture, not too late, and can be deformed with teeth. PP is white translucent, higher in transparency and lighter than PE, more rigid, and extremely difficult to deform with teeth.
(4) The difference between PS, HIPS and ABS is mainly PS brittleness, HIPS and ABS are toughness, so PS is brittle when bent. The latter two are difficult to break and whitish in the bent part. It is easy to identify before it is dyed; PS is transparent, HIPS is milky white, and ABS is light ivory.
Second, the combustion observation method
Different materials have different combustion behaviors when burning, such as the color and breath of the flame (the degradation of the plastic during the actual processing process will also have a low molecular weight), which is also the basic method for identifying commonly used materials.
The degree of burning, the situation after the fire, the color of the flame, the situation of the smoke, the melting situation, the breath
PE flammable, continuous burning, yellow, blue, rarely dripping paraffin
PP flammable, continuous burning, yellow, blue, less dripping, petroleum flavor
PS flammable, continuous burning, yellow, blue, blue, smoke, no blister, styrene
ABS flammable, continuous burning, all yellow, thick smoke, coking rubber
HIPS flammable, continuous burning, full yellow, thick smoke, no blistering, foaming, rubbery
PMMA slow burning, continuous burning, light blue, white, no, no, no, no foam,
PA flammable, continuous burning, less dripping, burning hair
POM can burn, continue to burn, no drop, spicy taste
PET flammable, continuous burning, no drop, vinegar
PC slow burning, no burning, yellow, black smoke, carbon beam, foaming, fruity smell
PVC is difficult to burn, self-extinguishing, yellow, green, white, white, smoke, spicy