PA, PVC, PMMA, PC, POM, PE, PP, ABS, accurate introduction and stress testing
1. PA, PVC, PMMA, PC, POM, PE, PP, ABS, PS, EVA and some mixtures.
2. Common plastic characteristics and performance:
2.1. PA (nylon): 8026 upper cover, 532 support, 049D inner core, and the like.
1 The primary color is milky white and slightly brown. It burns slowly and slowly extinguishes after the fire. The flame is yellow and blue, melted and dripped, foaming, and has special sheepskin or nail charred smell. 2 better physical and mechanical properties,
3 Stress test: n-propane, B, no crack, crack.
2.2.PVC: Polyvinyl chloride
1 The primary color is colorless and transparent, and it is difficult to burn off from the fire. The flame is yellow and green, white smoke, and the burning is soft and pungent. Under ultraviolet light, PVC is light blue, purple and white. Soft PVC is blue or blue-white.
2 According to the different additives, it is divided into hard and soft. Hard PVC uses small molecular weight resin, does not contain 5% of the former, has good mechanical strength, corrosion resistance, sunlight resistance, and combustion resistance. The soft PVC adopts molecular weight. Large resin, added with 30%-70% increaser to make it flexible and chemically resistant.
2.3.PMMA: plexiglass, acrylic
1 The primary color is colorless, transparent, flammable, and continues to burn after leaving the fire. The flame is yellow and light blue, melted and dripped, heated to 120 °C to bend freely, not turbid, and emits a unique acrylic odor, easy Melted in acetone and benzene.
2 high transparency, high light resistance, high refractive index, self-adhesive with acetone, chloroform and other solvents, the product shrinkage rate of 0.1-0.8%, the hygroscopicity of the pellets can cause foaming of the product. 3 Stress test: Ethanol or isopropanol, no cracking or cracking for ten seconds.
2.4. POM: POM
1 The primary color is light yellow or white, slow burning, continue to burn after the fire, the flame is yellow and blue, melted and dripped, and the strong fish stinks.
2 Strong mechanical properties, shortcomings are not resistant to acid, strong alkali and radiation that is not resistant to sunlight. It will age in the atmosphere for a long time, and the adhesion is poor. 3 Stress test: Soak 2H in 12-18% hydrochloric acid solution, no deformation or crack.
2.5. PE: Polyethylene
1 The primary color is translucent - waxy, flammable, yellow and blue on the flame, dripping on the side of the melt, smell of paraffin, not melted in solvent at room temperature, soluble in acetone, benzene, formaldehyde when heated. 2 According to the processing method, it can be divided into high density PE and low density PE
The high-density PE is a translucent waxy solid with tough texture, water impermeability, abrasion resistance and chemical resistance. Disadvantages: After heating, the size is reduced due to the disappearance of stress, and the flexibility and resistance to cold and heat are poor.
Low-density PE is a colorless, odorless, non-toxic solid that retains its softness, water resistance and chemical stability at low temperatures. 3 Stress test: sodium stearate or soapy water, no deformation, cracks, breaks.
2.6. ABS: terpolymer of three monomers of acrylonitrile, butyl ethylene and styrene
1 The primary color is milky white or white, opaque, burning slowly, burning after leaving the fire, the flame is yellow, black smoke, softened and burnt, soluble in acetone, benzene, toluene.
2 acrylonitrile has tensile strength, thermal stability, chemical stability, butadiene has toughness, impact resistance and low temperature properties, styrene has good gloss, rigidity and processability; adjust the ratio between the three, Adjust high impact type, medium impact type, general purpose type, special heat resistant type ABS. Disadvantages: heat resistance is not high enough, easy to age, not flammable and opaque. 3 Stress test: 95% or more of acetic acid was immersed for 30 seconds without deformation, cracks and breakage.
1 The primary color is semi-transparent wax color, flammable, burning away from fire, yellow and blue on the flame, a small amount of black smoke, melting and dripping, giving off the smell of oil.
2 density 0.9m/cm3, one of the least dense plastics, melting point 164-170 ° C, strong chemical resistance (except concentrated HCL, concentrated sulfuric acid), poor flame resistance, sensitive to ultraviolet light, certain chlorinated hydrocarbons, aromatic hydrocarbons and The high boiling aliphatic hydrocarbon softens and swells.
2.8. EVA: ethylene, vinyl acetate copolymer
1 The primary color is colorless and transparent, similar to rubber thermoplastic resin, toughness, flexibility, stress crack resistance and adhesion.
2EVA resin with vinyl acetate content of 15%, AC foaming agent (oxydiformamide), DCP cross-linking agent (diisobenzene), if you want to form micro-air-air foam, the foaming agent must be placed after cross-linking. The gas, that is, the crosslinking agent decomposition temperature, is lower than the decomposition temperature of the blowing agent.
2.9. PC: Polycarbonate
1 The primary color is transparent and colorless. The slow burning can slow down after the fire, the flame is yellow, the black smoke carbon bundle, melting and foaming, giving a special flower and fruit scent. 2 outstanding impact strength, resistance to deformation, higher heat resistance, cold. Disadvantages: low fatigue resistance. PMMA using isopropanol or n-heptane/toluene (40/60 vol) for 3 min ABS/PC using ethyl acetate/methyl acetate (25/75 vol) for 3 min PC using toluene/n-propanol (10/90) Volume) Time 10min ABS can also use pure glacial acetic acid for 3min
1. ABS plastic was placed in 70% glacial acetic acid at 24 ° C for 0.5 minutes. Wash with water and blow dry to see if there is crack or whitening. If there is a dense crack indicating stress, the crack is more stress.
2. ABS was placed in a mixture of 1:1 methyl ethyl ketone and acetone at 21 ° C for 15 seconds, and dried as described above. 3. Polyacrylic acid for n-heptane, PC and polysulfone for carbon tetrachloride. . 4. When using the above experiment, do not use release agent