In summary, polypropylene has the following characteristics:
- Polypropylene is a polymer that arises from the polymerization of propylene.
- Either Ziegler-Natta or metallocene catalysts are required for polymerization. Their selection will depend on the type of polypropylene to be generated and the most suitable structure for the final product (isotactic, syndiotactic, atactic).
- Ziegler-Natta and metallocene polymerization of propylene yields highly isotactic, partially crystalline polypropylene with high stiffness and hardness.
- The raw material to be used in the process defines the type of PP produced (PP homopolymer, PP copolymer, PP copolymer).
- There are 3 classifications of processes to polymerize propylene. Inputs may vary in each process.
- The bulk process with liquid and gas phase monomer is currently the most widely used, and does not require an additional solvent, unlike the suspension process.
- The Spheripol process is the most commercially used mass process due to the improvements it offers over the suspension process. It can also be considered a hybrid process since it works with liquid phase reactors first and then with gas phase reactors.
- Worldwide, there are many petrochemical companies that are also dedicated to polymerizing not only PP but also other polymers and at the same time are responsible for their commercialization and transformation.
- There is no Covenin or ASTM standard that represents the PP polymerization process, only standards that regulate its transformation.
- The environmental impact of PP is more evident in the use of the finished product, i.e. there are more repercussions after the PP has been transformed.
- In the identification code of plastics it corresponds to number 5, it can be observed in plastic containers and food bags, etc. It is recyclable but resistant to biodegradation. Polypropylene, summary