Properties of Atactic Polypropylene (PP)
Atactic polypropylene (PP) is a synthetic polymer characterized by the random placement of methyl groups along its polymer chain. This irregularity leads to an amorphous, non-crystalline structure, differentiating it from isotactic forms.
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The following table provides a comprehensive list of polypropylene (atactic) properties in both SI and US customary/Imperial units at normal temperature and pressure (NTP).
Click on the button to switch between Metric and Imperial units.
| Physical Properties | Metric |
|---|---|
| Category | Thermoplastic |
| Density | 850 - 900 kg/m3 |
| Water Absorption | 0.01 %wt/day |
| Mechanical Properties | Metric |
| Ultimate Tensile Strength | 21.4 MPa |
| Young’s Modulus (E) | 0.69 - 1.52 GPa |
| Flexural Modulus | 0.9 GPa |
| Elongation at Break | 300% |
| Rockwell Hardness (R) | 95 |
| Static Friction Coefficient (µ) | 0.1 - 0.3 |
| Thermal Properties | Metric |
| Melting Point | 176 °C |
| Thermal Conductivity | 0.12 W/m·K |
| Specific Heat Capacity (Cp) | 1960 J/kg·K |
| Coefficient of Thermal Expansion (αL) | 6.8×10-5 - 9.5×10-5 1/°C |
| Glass Transition Temperature (Tg) | -18 °C |
| Electrical Properties | Metric |
| Relative Permittivity (@1 MHz) (εr) | 2.2 - 2.3 |
| Electrical Resistivity | 1016 Ω·cm |
| Dielectric Field Strength (Ed) | 200 - 260 kV/cm |
| Hazardous Data | Metric |
| Flammability Rating (ANSI/UL 94) | Combustible |
Unless stated otherwise, all values are taken at room temperature (approximately 20°C or 68°F) and 1 atm pressure. (1 atm = 101,325 Pa)
References: 1) Cardarelli, François. Materials Handbook: A Concise Desktop Reference. Switzerland: Springer International Publishing, 2018. 2) CRC Handbook of Chemistry and Physics, 97th Edition. United Kingdom: CRC Press, 2016-2017. 3) A.M. Howatson, P.G. Lun, J.D. Todd, P.D. Engineering Tables and Data. United Kingdom: University of Oxford, Department of Engineering Science, 2009.