| Moisture regain | <0.1% |
| Refractive indexNnD23 | 1.49 |
| Thermal conductivity | 2.7x10-7 Kcal/cm/cm2.sn.oC |
| Heat of fusion | 21 cal/g |
| Specific heat | 0.46 cal/g.C |
| Density of melt at 180oC | 0.769 g/cc |
| Heat of combustion | 10,778 cal/gr |
| Oxygen index | 17.4 |
| Decomposition temperature range | 328-410oC |
| Dielectric constant (0.1 M Hz) | 2.25 |
| Dissipation factor (0.1 M Hz) | <0.0002 |
| Specific volume resistivity | >1016.cm |
| Resistance at 20°C | Concentration % | Residual Tenacity % (after 4 days) | |
| Hydrochloric Acid | 34 | 100 | |
| Nitric Acid | 65 | 90 | |
| Sulphuric Acid | 95 | 100 | |
| Formic Acid | 75 | 100 | |
| Glacial Acetis Acid | - | 100 | |
| Potassium Hydrate | 40 | 95 | |
| Sodium Hydrate |
40 |
100 | |
| Trichloroethylene | 80 | ||
| Perchloroethylene |
80 | ||
| Toluene | 98 | ||
| Benzene | 80 | ||
| Sodium Hypochlorite (5% active chlorine) |
85 | ||
| Hydrogen Peroxide (12 Parts) | 90 | ||
|
Resistance at 70°C |
Residual tenacity % | ||
| 6 hrs | 21 hrs | ||
| Sulphuric Acid | 94 | 100 | 95 |
| Glacial Acetic Acid | 100 | 95 | |
| Sodium Hydrate | 40 | 100 | 95 |
The degree of orientation achieved by drawing influences the mechanical properties of PP filaments. The greater the degree of stretch, the higher the tensile strength and the lower the elongation. Commercial PP monofilaments have an elongation at break in the region of 12-25%. Multifilaments and staple fibers are in the range of 20-30% and 20-35%, respectively.
Thermal properties
Polypropylene
fibers have a softening point in the region of 150oC and a
melting point at 160-170oC. At low temperatures of
-70oC or lower, PP fibers remain their excellent flexibility.
At high temperature (below 120oC) PP fibers nearly remain their
normal mechanical properties. PP fibers have the lowest thermal
conductivity of all commercial fibers. In this respect, it is the warmest
fiber of all. The thermal conductivity of common textile fibers is shown
in the table below:
| Material | Thermal conductivity relative to air |
| Air | 1.0 |
| PP | 6.0 |
| Wool | 6.4 |
| Acetate | 8.6 |
| Viscose | 11 |
| Cotton | 17.0 |
Other properties
In general, PP
fiber has excellent chemical resistance to acids and alkalis, high
abrasion resistance and resistance to insects and pests. PP fiber is also
easy to process and inexpensive compared to other synthetic fibers. Its
low moisture absorption helps quick transporting of moisture.
The main drawbacks of PP fibers are:
Due to low melting temperature it can be ironed with low temperatures
Hard to be dyed after manufacturing except being modified
Poor UV and thermal stability which requires addition of expensive UV stabilizers and antioxidants to overcome this problem,