Physical properties of polypropylene:
- An odorless solid.
- Translucent white.
- Spherical physical appearance, also known as "pallets."
- Boiling Point of 320 °F (160 °C)
- Melting Point 173°C
- The density of polypropylene ranges from 0.89 to 0.91 g/cm³. It is the lowest among commercial polymers. Because it is so low, it allows for the manufacture of lightweight products due to its mass-to-volume ratio.
- It is a stiffer material than most thermoplastics. A load of 25.5 kg/cm2, applied for 24 hours does not produce appreciable deformation at room temperature and resists up to 70 degrees C.
- It has excellent elastic recovery. In other words, it returns to its original dimensions once the stress is removed.
Chemical Properties of Polypropylene:
- It is nonpolar in nature and, as a result, is highly resistant to chemicals. In other words, this polymer does not interact directly with other chemicals (e.g., acids).
- It has low water absorption; therefore, it does not retain much moisture, as it has a low moisture absorption coefficient (0.02 kg/m²·h⁰.⁵)
- Polypropylene has good chemical resistance but poor resistance to UV rays, which causes degradation. UV energy absorbed by plastics can excite photons, which then create free radicals. While many pure plastics cannot absorb UV radiation, the presence of catalyst residues and other impurities often acts as a receptor and causes degradation (chalky appearance and discoloration).
- The PP is resistant to organic solvents (e.g., chloroform, acetone, tetrahydrofuran)
- PP is insoluble in water.