Polypropylene (PP)
Polypropylene is a type of thermoplastic polymer resin with the chemical formula C3H6. It is useful in many packaging applications as a structural plastic or as a fiber-type plastic. It is easy to customize, lightweight and very flexible, and has high melting point and a low level of electrical conductivity. Polypropylene (PP) is a versatile thermoplastic – it is the lightest polymers among all commodity plastics, low density, stress-cracking resistant and the list goes on. It is the second-most widely produced volume plastic after polyethylene.
Molecular Structure of polyproplene
Types of Polypropylene
Homopolymers and Copolymers are the two major types of polypropylene available in the market.
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- Polypropylene Homopolymer is the most widely utilized general-purpose grade. It contains only propylene monomer in a semi-crystalline solid form. Main applications include packaging, textiles, healthcare, pipes, automotive and electrical applications.
- Polypropylene Copolymer family is further divided into random copolymers and block copolymers produced by polymerizing of propene and ethane:
- Polypropylene Random Copolymer is produced by polymerizing together ethene and propene. It features Ethene units, usually up to 6% by mass, incorporated randomly in the polypropylene chains. These polymers are flexible and optically clear making them suitable for applications requiring transparency and for products requiring an excellent appearance.
- While in Polypropylene Block Copolymer, ethene content is larger (between 5 and 15%). It has co-monomer units arranged in regular pattern (or blocks). The regular pattern hence makes thermoplastic tougher and less brittle than the random co-polymer. These polymers are suitable for applications requiring high strength, such as industrial usages.