1. Physical properties: Polypropylene is a non-toxic, odorless, odorless, milky, highly crystalline polymer with a density of only 0.90~.091g/cm3. It is one of the lightest varieties in all plastics. It is particularly stable to water, with a water absorption rate of 0.01% in water for 24 hours and a molecular weight of about 8 to 150,000. Good moldability, but due to high shrinkage, thick-walled products are easily sag. The surface of the product is glossy and easy to color.
2. Mechanical properties: Polypropylene has high crystallinity and structural regularity, so it has excellent mechanical properties, its strength and hardness, elasticity are higher than HDPE, but at room temperature and low temperature, due to its high degree of structural regularity of the molecular structure, so The impact strength is poor, and when the molecular weight increases, the impact strength also increases, but the molding process performance deteriorates. PP's most prominent performance is the resistance to bending fatigue, such as the use of PP injection one living hinge, can withstand 7 × 107 times the folding bending without damage, dry friction coefficient and nylon similar, but under the oil lubrication, not as good nylon.

3, thermal properties: PP has good heat resistance, the melting point of 164 ~ 170 °C, products can be more than 100 °C temperature sterilization, without external force, 150 °C is not deformed. The embrittlement temperature is -35°C, and embrittlement will occur below -35°C. Cold resistance is inferior to polyethylene.

4, chemical stability: polypropylene chemical stability is very good, in addition to being able to be eroded by concentrated sulfuric acid, concentrated nitric acid, other kinds of chemical reagents are relatively stable, but low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons, etc. Can make PP soften and swell, at the same time, its chemical stability increases with the increase of crystallinity, so polypropylene is suitable for making all kinds of chemical pipelines and accessories, with good anti-corrosion effect.

5, electrical properties: polypropylene high-frequency insulation performance is excellent, because it is almost no water, so the insulation performance is not affected by the humidity. It has a high dielectric coefficient, and with the rise of temperature, it can be used to make heated electrical insulation products, and its breakdown voltage is also high, suitable for use as electrical accessories. The resistance to voltage and arc resistance is good, but the degree of static electricity is high and it is easy to age with contact with copper.

6, weather resistance: Polypropylene is very sensitive to ultraviolet light, adding zinc oxide, dilauryl thiopropionate, carbon black or similar cream filler can improve its aging resistance.

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