Simple Identification Method of Plastic Variety
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Key words：Simple Identification Method of Plastic Variety
Plastic identification can use infrared spectrometer, paramagnetic resonance instrument and X-ray and other scientific methods, but can also be used to identify more simple method. The following briefly describes the simple authentication method:
Sensory identification (organization of students involved in the identification of plastic)
Look at the color of products, transparency.
Transparent products are: polystyrene and plexiglass.
Translucent products are: low-density polyethylene, cellulose plastic, PVC, polypropylene, epoxy resin, unsaturated resin.
Opaque products are: high-density polyethylene, polyurethane and various colored plastic.
With hard objects percussion, the sound is different, polystyrene-like metal sound, plexiglass its sound coarse, nausea.
Hand touch products feel like waxy, must be polyolefin material. Secondly, the degree of its hard and soft, can be simply expressed as follows:
Hard → soft
Polystyrene → polypropylene → polyamide → plexiglass → high density polyethylene → hard polyvinyl chloride → low density polyethylene → soft polyvinyl chloride
And then test the surface hardness, pencil with a different hardness of its surface, you can make a difference:
Polyethylene plastic with HB pencil to draw line marks;
Polypropylene plastic with the ZH pencil to draw line marks.
Due to the differences in physiological conditions, sensory identification is not the same feeling, so this approach is for reference only.
Identification of several easily mixed plastics
(A) polyethylene and polypropylene plastic basis for identification
Polyethylene and polypropylene plastic are translucent milky white, light to float on the water, the combustion phenomenon is basically the same. However, there are obvious differences between the two: polyethylene hand touch of a waxy greasy feeling, soft texture can bend, and smooth hand touching the fine polypropylene, but no waxy creamy texture, the texture is very tough toughness; polyethylene plastic in the Boiling water significantly softened, polypropylene plastic softening in boiling water is not significant; polyethylene plastic stretch like a "thin neck", while the polypropylene is not.
(B) polyvinyl chloride and polyethylene plastic film based on the identification
PVC and polyethylene processing methods are different: PVC pressed into a single film by the rolling method, polyethylene blown into a tubular double-layer bag; from the color and transparency: polyethylene milky white translucent, The surface is bright, hand-touch waxy creamy sense of multi-layer stack together still translucent milky white, and PVC transparency than polyethylene high, yellowish color, multi-layer stack together yellow, smooth hand touch , But there are sticky feeling, careful observation of mold fine lines; burning phenomenon: polyethylene flammable, melt dripping, paraffin, and PVC flame retardant, the root of the flame was green, and hydrochloric acid irritating odor Release; small proportion of polyethylene can float in the water, and PVC sank in water.
(C) the identification of phenolic and urea-formaldehyde basis
Both are thermosetting plastics, with a hard and opaque characteristics, mainly the following differences: phenolic plastic is generally dark brown, urea-formaldehyde plastic mostly light-colored, and bright color; phenolic plastic cross-section structure is loose, and urea-formaldehyde plastic section Structure close; burning, phenolic smell of phenol release, contact with the flame appeared part of the phenomenon of carbonization, urea smell of urea to escape, and the flame at the junction of white cracking phenomenon.
(D) polystyrene, polyvinyl chloride, polyethylene plastic identification basis
The identification of the three plastic according to the following five aspects:
1. Color and transparency
Polystyrene plastic bright colors, transparency, such as glass; PVC plastic color and transparency than the poor polystyrene; polyethylene plastic translucent body, the appearance of such as wax products, and the dye easily leaking.
Polystyrene feel smooth, hard surface, for fear of bump, fear of extrusion; PVC handle is relatively smooth, thin film products are sticky feeling; soft and hard products of the points; polyethylene waxy feel feel creamy , Products, soft-resistant bending fracture.
3. Relative density
The relative density of polystyrene l.05 ~ 0.06, on the slow sinking in water; PVC soft plastic relative density of 1.24 ~ 1.45, the relative density of rigid plastic 1.35 ~ 1.45, it is in the water under the rapid High density polyethylene relative density of 0.94 to 0.97, low density of the relative density of 0.91 to 0.93, it is floating in the water.
Hard objects percussion, polystyrene has a crisp sound of metal, PVC ring rather than brittle, brittle and not brittle polyethylene.
Polystyrene flammable, the flame was orange, smoky black smoke, pungent smell of unpleasant styrene monomer; PVC can not spontaneous combustion, from the fire off, the flame yellow, green roots, hydrochloric acid odor released ; Polyethylene flammable, the flame is yellow, the root is blue, take a small amount of black smoke, softening when burning, like a candle dripping wax tears, a paraffin odor released.