Properties of Polystyrene (PS)
Polystyrene is a synthetic polymer made from the monomer styrene. It is a versatile plastic widely used in various forms, including solid and foam. Solid polystyrene is rigid and used in products like disposable cutlery, CD cases, and packaging materials. Expanded polystyrene (EPS) foam is popular for insulation, packaging, and disposable food containers.
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).
Click on the icon to switch between Metric and Imperial units.
| 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)
Related Pages
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.