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.

Looking to buy polymers?
Check pricing and availability through our trusted partner:

Online Metals - High-quality polymers with fast shipping

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 button to switch between Metric and Imperial units.

Table of Polystyrene Properties
Physical Properties
Metric
CategoryThermoplastic
Density1054 - 1070 kg/m3
Water Absorption0.4 %wt/day
Mechanical PropertiesMetric
Ultimate Tensile Strength27 - 69 MPa
Ultimate Compressive Strength83 - 117 MPa
Young’s Modulus (E)2.3 - 4.1 GPa
Flexural Modulus3.17 GPa
Elongation at Break1.6 - 3%
Rockwell Hardness (M)60 - 90
Thermal PropertiesMetric
Melting Point115 °C
Thermal Conductivity0.10 - 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 Temperature109 °C
Electrical PropertiesMetric
Relative Permittivity (@1 MHz) (εr)2.4 - 3.1
Electrical Resistivity1016 Ω·cm
Dielectric Field Strength (Ed)180 - 240 kV/cm
Optical PropertiesMetric
Refractive Index (589 nm)1.59 - 1.60
Hazardous DataMetric
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.