Physical properties of polypropylene:
- Odorless solid.
- White-transparent color.
- Spherical physical appearance or also called pallets.
- Boiling point of 320°F (160°C)
- Melting point 173°C
- The density of polypropylene is between 0.89 and 0.91 g/cm3. It is the lowest of the commercial polymers. Because it is so low, it allows the manufacture of lightweight products due to its mass/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 a great capacity of elastic recovery. That is to say, it recovers its original dimensions after an effort is removed.
Chemical properties of polypropylene:
- It has an apolar nature, and therefore has great resistance to chemical agents. That is to say, the direct interaction of this polymer with other chemicals (e.g. acids) is difficult.
- It presents little water absorption, therefore it does not present much humidity since it has a low humidity absorption coefficient (0.02 kg/m2 . h0.5).
- Polypropylene has good chemical resistance but weak UV resistance, leading to 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 act as receptors and cause degradation (chalky appearance and color change).
- PP is resistant to organic solvents (e.g. Cloform, acetone, tetrahydrofuran).
- PP is insoluble in water.