Polystyrene (PS) is economical, and is used for producing plastic model assembly kits, plastic cutlery, CD "jewel" cases, smoke detector housings, license plate frames, and many other objects where a fairly rigid, economical plastic is desired. Production methods include thermoforming and injection molding.
Polystyrene Petri dishes and other laboratory containers such as test tubes and microplates play an important role in biomedical research and science. For these uses, articles are almost always made by injection molding, and often sterilized post-molding, either by irradiation or treatment with ethylene oxide. Post-mold surface modification, usually with oxygen-rich plasmas, is often done to introduce polar groups. Much of modern biomedical research relies on the use of such products; they therefore play a critical role in pharmaceutical research.

Density 1.05 g/cm3
Density of EPS 16–640 kg/m3[4]
Dielectric constant 2.4–2.7
Electrical conductivity (s) 10−16 S/m
Thermal conductivity (k) 0.08 W/(m·K)
Young's modulus (E) 3000–3600 MPa
Tensile strength (st) 46–60 MPa
Elongation at break 3–4%
Notch test 2–5 kJ/m2
Glass transition temperature 95 °C
Melting point[5] 240 °C
Vicat B 90 °C[6]
Linear expansion coefficient (a) 8×10−5 /K
Specific heat (c) 1.3 kJ/(kg·K)
Water absorption (ASTM) 0.03–0.1