Properties of High Impact Polystyrene (HIPS)
High Impact Polystyrene (HIPS) is a versatile thermoplastic known for its strength and impact resistance, achieved by blending polystyrene with rubber additives like polybutadiene. This material offers excellent machinability, dimensional stability, and ease of processing, making it ideal for applications across consumer goods, packaging, and industrial manufacturing.
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The following table provides a comprehensive list of high impact polystyrene (HIPS) 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 | 1040 kg/m3 |
| Water Absorption | 0.1 %wt/day |
| Mechanical Properties | Metric |
| Ultimate Tensile Strength | 35 - 100 MPa |
| Yield Tensile Strength | 25 MPa |
| Young’s Modulus (E) | 1.6 - 2.4 GPa |
| Flexural Modulus | 2.07 GPa |
| Poisson’s Ratio (ν) | 0.34 |
| Elongation at Break | 36 - 50% |
| Rockwell Hardness (L) | 73 |
| Thermal Properties | Metric |
| Thermal Conductivity | 0.124 W/m·K |
| Specific Heat Capacity (Cp) | 1250 J/kg·K |
| Coefficient of Thermal Expansion (αL) | 9×10-5 1/°C |
| Glass Transition Temperature (Tg) | 100 °C |
| Vicat Softening Temperature | 98 °C |
| Electrical Properties | Metric |
| Relative Permittivity (@1 MHz) (εr) | 2.3 - 2.5 |
| Electrical Resistivity | 1016 Ω·cm |
| Dielectric Field Strength (Ed) | 177 - 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)