Natta (1903-1979) is a famous Italian chemist. In 1954, he discovered the major discovery of low pressure ethylene polymerization of ethylene by German chemist K. Ziegler and found that titanium trichloride and alkyl aluminum were As for the catalyst, propylene is polymerized under low pressure with high yield, and a stereospecific polymer with high molecular structure, ie, polypropylene, is produced, which has a high strength and a high melting point and opens up a new field of stereospecific polymerization. This lays the foundation for a modern method of synthetic polypropylene that is widely used today.
In 1957, he was directly involved in the establishment of the world's first polypropylene production facility in Italy, and his discovery led to the introduction of a large variety of synthetic resins and plastics.
Natta also specifically studied the spatial structure of crystalline polypropylene, and elucidated their mechanism of action and molding rules, respectively.
In view of Nataâ€™s achievements, he won the 1963 Nobel Prize in Chemistry along with Ziegler, the inventor of the polyethylene industry.
PP plastic, chemical name: polypropylene English name: Polypropylene (referred to as PP)
Specific gravity: 0.9-0.91 g/cm3 Molding shrinkage: 1.0-2.5%
Molding temperature: 160-220Â°C
Features: Small density, strength and stiffness, hardness and heat resistance are all better than low-pressure polyethylene, can be used at about 100 degrees. It has good electrical properties and high frequency insulation resistance from humidity, but it becomes brittle and not wearable at low temperature. , Easy to age. Suitable for the production of general mechanical parts, corrosion resistance parts and insulation parts molding characteristics:
1. Crystalline material, low moisture absorption, easy to melt rupture, long-term contact with hot metal is easy to decompose.
2. The fluidity is good, but the shrinkage range and the shrinkage value are large, and the shrinkage hole, dent, deformation,
3. Cooling speed, pouring system and cooling system should be slowly cooling, and pay attention to control the molding temperature. The material temperature is easy to be oriented at low temperature and high pressure. When the mold temperature is lower than 50 degrees, the plastic parts are not smooth, welding defects, flow marks are easy to occur, and warpage and deformation are easily generated above 90 degrees.
4. The wall thickness of the plastic must be uniform to avoid lack of glue and sharp corners to prevent stress concentration.
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