Simple identification method of plastic varieties

Identification of plastics can be used infrared spectroscopy, ESR and X-ray instrument such as the scientific method, but can also use a more simple method of identification. Following is a brief simple method of identifying
First, the identification of sensory
Sensory identification (organize students to participate in the identification of plastics)
(A) see
Look at products, color, transparency.
Transparent products are: polystyrene and plexiglass.
Translucent products are: low density polyethylene, cellulose plastics, polyvinyl chloride, polypropylene, epoxy resin, unsaturated resin.
Opaque products are: high density polyethylene, polyurethane and various colored plastic.
(B) listen to
When struck with hard objects, their sound different, like polystyrene, metal sound, the sound of thick plexiglass, nausea.
(C) touch
Sense of touch products like wax, and must be polyolefin material. Secondly, the hardness of the mold can be simply expressed as follows:
Hard → soft
Polystyrene, polypropylene → → → glass → polyamide high-density polyethylene low-density polyethylene → → → PVC Soft PVC
Re-test the surface hardness, hardness pencil draw a different surface, you can make a difference:
Polyethylene plastic with an HB pencil to draw the line mark;
Polypropylene plastic with a pencil to draw the line ZH marks.
Differences in physiological conditions as people, not the same feeling of sensory identification of income, so this method only for reference. http://www.prmindustry.com/
Abstract...Articles section Second, the basis for identification of several Analogues plastic
(A) polyethylene and polypropylene plastic identification based on
Polyethylene and polypropylene are milky white translucent plastic body, light and can float on water, burning the same phenomenon. However, there are two significant differences: polyethylene wax hand touch with creamy, soft to bend and touch the smooth and delicate hand-PP, but no waxy creamy, texture, well connected and resilient; polyethylene plastic in the significantly softened in boiling water, boiling water to soften the polypropylene plastic is not significant; polyethylene plastic of the kind of tension there, "narrow neck" generation, and PP were not.
(B) PVC and polyethylene plastic film based on the identification of
PVC and polyethylene processing in different ways: PVC pressed into law by rolling single film, polyethylene to blow into a tube-shaped double-bags the rule of law; see from the color and transparency: translucent white polyethylene, surface than the light, creamy wax hand there is a sense of touch, multi-layer stacked continued to show a milky translucent, polyethylene and polyvinyl chloride than the high transparency, color yellow, multi-layer stacked yellow, smooth hand touch , but there are sticky feeling, carefully observe the appearance of fine lines with mold; combustion phenomena are different: polyethylene flammable, melt dripping, a paraffin smell, and flame retardant PVC, the roots of green flame, and a pungent smell of hydrochloric acid release; small proportion of polyethylene can float on water, and PVC sink in water.
(C) phenolic and urea-formaldehyde plastic identification based on
Both are thermosetting plastics, with hard and opaque features, mainly the following differences: generally dark brown Bakelite, urea-formaldehyde plastic, mostly light and bright color; Bakelite section loose, and urea-formaldehyde plastic section compact structure; combustion, phenolic odor of phenol release, contact with the flame portion of charring cracking phenomenon, urea-formaldehyde with urea smell escape contact with the flame occurring at the white cracking phenomenon.
(D) of polystyrene, polyvinyl chloride, polyethylene plastic identification based on
Basis for identification of these three plastics have the following five aspects.
1. Color and transparency
Polystyrene plastic brightly colored, transparent as glass; the color and transparency of PVC less capable than the polystyrene; translucent polyethylene plastic body, the appearance of products such as wax and dyes easily leaking.
2. Feel
Polystyrene feel smooth, hard surface, bump afraid, afraid of squeezing; PVC feel relatively smooth, thin-film products are sticky feeling; the software and hardware products to the other; polyethylene wax creamy feel a sense of , products, soft and resistant to bending.
3. Relative density
The relative density of polystyrene l.05 ~ 0.06, on the water slowly sinking; PVC soft plastic of the relative density of 1.24 to 1.45, the relative density of hard plastic is 1.35 ~ 1.45, so fast in the water under the Shen; the relative density of high-density polyethylene 0.94 ~ 0.97, the relative density of low-density 0.91 to 0.93, it is floating in the water.
4. Sound
When struck a hard object, a crisp metallic sound of polystyrene, polyvinyl chloride ring and not brittle, but not stuffy brittle polyethylene.
5. Flammability
Polystyrene flammable, the flame was orange, take flocculent smoke, a pungent unpleasant odor of styrene monomer; PVC can not be spontaneous combustion from the fire extinguished, the flame yellow, green roots, there is smell of hydrochloric acid released ; polyethylene flammable, the flame is yellow, blue roots, take a small amount of smoke, burning to soften, as the candle wax dripping tears, a paraffin odor release.

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          Peter  Huang