Properties of Polystyrene (PS)
Polystyrene (PS) is a synthetic thermoplastic polymer derived from styrene, known for its versatility in both solid and foam forms. Common applications include disposable cutlery, CD cases, packaging materials, and thermal insulation.
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The following table provides a comprehensive list of polystyrene (PS) properties in both SI and US customary/Imperial units at normal temperature and pressure (NTP).
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| Physical Properties | Metric |
|---|---|
| Category | Thermoplastic |
| Density | 1054 - 1070 kg/m3 |
| Water Absorption | 0.4 %wt/day |
| Mechanical Properties | Metric |
| Ultimate Tensile Strength | 27 - 69 MPa |
| Ultimate Compressive Strength | 83 - 117 MPa |
| Young’s Modulus (E) | 2.3 - 4.1 GPa |
| Flexural Modulus | 3.17 GPa |
| Elongation at Break | 1.6 - 3% |
| Rockwell Hardness (M) | 60 - 90 |
| Thermal Properties | Metric |
| Melting Point | 115 °C |
| Thermal Conductivity | 0.10 - 0.13 W/m·K |
| Specific Heat Capacity (Cp) | 1250 J/kg·K |
| Coefficient of Thermal Expansion (αL) | 3×10-5 - 2.1×10-4 1/°C |
| Glass Transition Temperature (Tg) | 100 °C |
| Vicat Softening Temperature | 109 °C |
| Electrical Properties | Metric |
| Relative Permittivity (@1 MHz) (εr) | 2.4 - 3.1 |
| Electrical Resistivity | 1016 Ω·cm |
| Dielectric Field Strength (Ed) | 180 - 240 kV/cm |
| Optical Properties | Metric |
| Refractive Index (589 nm) | 1.59 - 1.60 |
| Hazardous Data | Metric |
| Flammability Rating (ANSI/UL 94) | V-0 |
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.