Polypropylene is a linear hydrocarbon containing little or no unsaturation, resembling 
polyethylene;however the -CH3 groups cause stiffening and less stability with regard to oxidation.
Plasticized by elastomers (e.g. nitrile rubbers) and best by copolymerisation.
Solvents: at elevated temperatures aromatic hydrocarbons (e.g. xylene, tetralin, decalin).
Combustion: burns with blue-based non-smokey flame.

Specific gravity: films 0.89, general purpose 0.9 to 0.91, fibers 0.9 to 0.92
Refractive index: 1.49
Water absorbtion: 0.01 to 0.03% in 24 hours
Water retention: 5%
Specific heat: 0.46 at 40 deg. C
               0.5 at 100 deg. C
Coeff. of linear expantion: 0.00011 at 20 -60 deg. C
                            0.00015 to 0.00017 at 60 to 100 deg. C
                            0.00021 at 100-140 deg. C

Electrical properties
Resistivity: 1016  (ohm cm)
Dielectric strength: >32 (kV/mm)
Dielectric constant: 2.25

Mechanical properties
Young modulus: 120 (daN/mmm2)
Extension at break: 20-300%
Flexural yield strength: 4.2 to 4.9 (daN/mm2)
Compressive yield strength: general purpose, 3.8-4.6 (daN/mm2)
                            high impact, 3.1 (daN/mm2)
Flexural modulus: 110 (daN/mm2)
Impact strength: (Izod ft lb/in) general purpose, 0.4-2.2
                                 high impact, 1.5-12.
Hardness (Rockwell): general purpose, R80-R90
                     high impact, R28-R90
Friction: (polymer/polymer) 0.1-0.3