A manufacturer specializing in plastic products

Polypropylene is what chemical raw materials?

by:Qusheng     2020-11-11
Polypropylene ( PP) The ziegler - Natalia catalysts make propylene polymerization and, it is the crystallization of molecular chain section is arranged very neat isotactic polymer. Polymerization process production methods are: solvent polymerization ( Slurry method) , ontology, gas ontology in liquid phase polymerization and solution polymerization of 4. But they are mainly solvent method ( Slurry method) Polymerization is given priority to, the isotactic degree is over 95%, molecular weight of about 8 ~ 150000. ( 1) Physical properties of polypropylene is non-toxic, odourless, tasteless ivory high crystallization of polymer, the density is only 0. 90-0. 91 g/cm3, which is one of the lightest of all plastic brand. It particularly stable to water, in water for 24 h bibulous rate is only 0. 01%, the molecular weight of about 8 ~ 150000. Good formability, but due to the shrinkage rate ( Is 1% ~ 2. 5%) For some size, thick wall products easy sag, high precision parts, also difficult to meet the requirements. Products surface gloss, easy coloring. ( 2) High mechanical properties of polypropylene crystallinity, neat structure, thus has excellent mechanical properties, its yield, tensile and compression strength and hardness, elasticity, etc are all higher than HDPE, but at room temperature and low temperature, due to the molecular structure of the itself neat degree is high, so the impact strength is poorer, the molecular weight increased, the impact strength also increase, but the processing performance. Polypropylene has outstanding resistance to bending fatigue strength, such as in PP injection - Hinge body activity, can withstand the seventy million open closed folding bending without damage, the friction resistance is better also, dry friction coefficient and nylon are similar, but when oil lubrication, the friction performance obviously than nylon, PP can only be used to make PV value is low and is not affected by impact load of the gear and bearing. In terms of surface effect, such as in the products surface embossing, sculpture, is easier than any other thermoplastic. Polypropylene products particularly sensitive gap. When design the mould must pay attention to avoid the Angle exists, otherwise it will easy to produce stress concentration, affect the service life of the product. ( 3) The thermal properties of polypropylene with good heat resistance. Its melting point is 164 ~ 170 ℃, products can be above 100 ℃ temperature disinfection sterilization. In 150 ℃ are not subject to any external force, deformation, the stress relaxation performance is good, the resistance of 90 ℃ its brittle temperature was minus 35 ℃, below - 35 ℃ temperature embrittlement happens, cold tolerance than polyethylene, if use asbestos fiber and glass fiber reinforced, had a higher heat distortion temperature, dimensional stability, low temperature impact performance. ( 4) Chemical stability of polypropylene has a good chemical stability, besides can be concentrated sulfuric acid and nitric acid erosion, for other kinds of chemical reagents are stable, but the low molecular weight fatty hydrocarbon and aromatic hydrocarbons and chlorinated hydrocarbon can make polypropylene softening and swelling, and its chemical stability at the same time there is some increase with the increase of the crystallinity. So, it is suitable for all kinds of chemical pipe and fittings, the anti-corrosion effect is good. ( 5) High frequency of electric properties of polypropylene insulation performance is good, because it is almost not bibulous, insulation performance is not affected by moisture. It has high dielectric coefficient, and increase with increasing temperature, can be used to make the heated electrical insulation products, it is also high breakdown voltage, suitable for electric parts, etc. Good resistance to voltage, arc resistance, electrostatic degree is high, but contact with copper aging. ( 6) Weathering polypropylene is sensitive to uv light, by adding zinc oxide, sulfur, generation of propionic acid second laurel oil, carbon black, or similar milky white filler can improve the aging resistance performance.
Custom message
Chat Online 编辑模式下无法使用
Chat Online inputting...