Polypropylene (PP)

Polypropylene (PP) is a thermoplastic polymer made from the monomer propylene (or propene). It belongs to the polyolefin family and is produced through chain-growth polymerization of propylene using catalysts such as Ziegler–Natta or metallocenes. Polypropylene is known for its low density, high chemical resistance, toughness, and versatility. It can be easily molded, extruded, or spun into fibers and films. PP is widely used in packaging, textiles, automotive components, medical devices, and consumer products. It is resistant to moisture, many acids, and bases, making it suitable for containers and piping. The polymer can exist in isotactic, syndiotactic, or atactic forms, with isotactic PP being the most common and crystalline. It has a melting point around 160–170 °C and is recyclable, typically classified as plastic number 5.