The material. Polystyrene is an optically clear, cheap, easily molded polymer, familiar as the standard "jewel" CD case. In its simplest form PS is brittle. Its mechanical properties are dramatically improved by blending with polybutadiene but with a loss of optical transparency. High-impact PS (10% polybutadiene) is much stronger, even at low temperatures (meaning strength down to -12°C). The single largest use of PS is a foam packaging.
|
Composition (CH(C6Hs)-CH2)n |
||
|
General properties |
||
|
Density |
1040 |
– 1050 kg/m3 |
|
Price |
1.81 |
– 1.99 USD/kg |
|
Mechanical properties Young’s modulus |
1.2 |
– 2.6 |
GPa |
|
Yield strength (elastic limit) |
28.7 |
– 56.2 |
MPa |
|
Tensile strength |
35.9 |
– 56.5 |
MPa |
|
Compressive strength |
31.6 |
– 61.8 |
MPa |
|
Elongation |
1.2 |
– 3.6 |
% |
|
Hardness—Vickers |
8.6 |
– 16.9 |
HV |
|
Fatigue strength at 107 cycles |
14.4 |
– 23 |
MPa |
|
Fracture toughness |
0.7 |
– 1.1 |
MPa. m1/2 |
|
Thermal properties Glass temperature |
73.9 |
– 110 |
°C |
|
Maximum service temperature |
76.9 |
– 103 |
°C |
|
Thermal conductor or insulator? |
Good |
insulator |
|
|
Thermal conductivity |
0.121 |
– 0.131 |
W/m. K |
|
Specific heat capacity |
1690 |
– 1760 |
J/kg. K |
|
Thermal expansion coefficient |
90 |
– 153 |
p, strain/°C |
|
Electrical properties Electrical conductor or insulator? |
Good insulator |
|
|
Electrical resistivity |
1 X 1025 |
– 1 X 1027 pnhm. cm |
|
Dielectric constant |
3 |
– 3.2 |
|
Dissipation factor |
0.001 |
– 0.003 |
|
Dielectric strength |
19.7 |
– 22.6 106 V/m |
Polystyrene is water-clear, easily formed, and cheap. Ecoproperties: material
|
Annual world production |
1.2 X 107 |
– 1.22 X 107 |
tonne/yr |
|
Reserves |
*3 X 108 |
– 3.1 X 108 |
tonne |
|
Embodied energy, primary production |
86 |
– 99 |
MJ/kg |
|
CO2 footprint, primary production |
2.7 |
– 3 |
kg/kg |
|
Water usage |
*108 |
– 323 |
l/kg |
|
Eco-indicator |
340 |
– 380 |
millipoints/kg |
|
Ecoproperties: processing |
|||
|
Polymer molding energy |
*10.3 |
– 11.3 |
MJ/kg |
|
Polymer molding CO2 |
*0.82 |
– 0.90 |
kg/kg |
|
Polymer extrusion energy |
*3.97 |
– 4.37 |
MJ/kg |
|
Polymer extrusion CO2 |
*0.31 |
– 0.35 |
kg/kg |
|
Recycling |
|||
|
Embodied energy, recycling |
36.1 |
– 41.6 |
MJ/kg |
|
CO2 footprint, recycling |
1.1 |
– 1.2 |
kg/kg |
|
Recycle fraction in current supply Recycle mark |
2.1 PS |
– 3 |
% |
Typical uses. Toys; light diffusers; lenses and mirrors; beakers; cutlery; general household appliances; video/audio cassette cases; electronic housings; refrigerator liners.
