Spunbonded Polypropylene (PP)
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Property
| Polymer | Polypropylene (C3H6)n |
| Symbol | PP |
| Degree of crystallinity | High, varies with processing |
| Modulus of Elasticity | 1400 MPa |
| Tensile strength | 35 MPa |
| Elongation | 10-500% (depends on additives) |
| Specific Gravity | 0.90 |
| Glass Transition temperature | -20°C |
| Melting temperature | 176°C |
Typical Physical Property (PP roofing underlayment)
| Test type | Standard (Test Method) | Typical Value |
| Moisture Vapour Transmission | ASTM E96-66 | 0.67 g/ 100 in²/ day |
| Grab Tensile Strength
MD lbs/in CD lbs/in |
ASTM D 1682 |
131 116 |
| Trapezoidal tear
MD lbs CD lbs |
CGSB 4-GP-2 12.2 |
49 33 |
| Beach puncture | Tappi T-803 om-79 | 3.4 Joules |
| Porosity | Tappi T-460 os-75 | Non Porous |
| Brittleness Temperature | -67°F | |
| Water Permeability | no leaks after 24 hrs with 2″ water head | |
| Weatherability | retained 97.9% of original strength, at equivalent to 3 years of outdoor exposure |