Polypropylene

Here are some key points about polypropylene:

1. Chemical Composition and Production:
   • Polypropylene is produced via chain-growth polymerization from the monomer propylene.
   • It belongs to the group of polyolefins and is partially crystalline and non-polar¹.
2. Properties:
   • Density: Polypropylene has a density of 855 g/cm³ in its amorphous form and 0.946 g/cm³ in its crystalline form.
   • Melting Point: The melting point of polypropylene ranges from 130 to 171°C (266 to 340°F; 403 to 444 K).
   • Mechanical Properties: It is slightly harder than polyethylene and has high chemical resistance.
   • Heat Resistance: Polypropylene is more heat-resistant than polyethylene.
   • Color: It is a white material.
   • Chemical Resistance: Polypropylene exhibits high chemical resistance¹.
3. History:
   • The polymerization of propylene was first demonstrated by Phillips Petroleum chemists J. Paul Hogan and Robert Banks in 1951.
   • The stereoselective polymerization to the isotactic form was discovered by Giulio Natta and Karl Rehn in March 1954.
   • Large-scale commercial production of isotactic polypropylene began in 1957 by the Italian firm Montecatini.
   • Ongoing research continues to explore making polypropylene from bio-based resources¹.
4. Applications:
   • Polypropylene is widely used in various fields, including:
     • Clothing
     • Medical devices
     • Plastic products
     • Fibers
     • Copolymers
     • Biaxially oriented polypropylene (BOPP)
     • Recycling
     • Repairing
   • It is the second-most widely produced commodity plastic after polyethylene^{1 2}.

In summary, polypropylene is a versatile material with excellent properties, making it suitable for diverse applications in industry and everyday life^{1 2}.