General Purpose Polystyrene (GPPS)
GPPS (General Purpose Polystyrene) is a transparent thermoplastic polymer produced by the polymerisation of styrene. The material features high rigidity, good transparency and a glossy surface. Thanks to its excellent flowability, it is widely used in injection moulding and extrusion.
General-purpose polystyrene is a cost-effective material for producing transparent, rigid products.
Key properties
- High transparency
- Glossy surface
- Good rigidity
- Easy processing
- Low impact resistance (the material is brittle)
- Low moisture absorption
Physical and mechanical properties (typical values) | |
Property | Typical values |
Density | 1.04 – 1.06 g/cm³ |
MFI (200°C / 5 kg) | 2 – 20 g/10 min (depending on grade) |
Tensile strength | 40 – 50 MPa |
Modulus of elasticity | 2800 – 3200 MPa |
Impact strength (Izod) | 1.5 – 3 kJ/m² |
Glass transition temperature (Tg) | ~95 – 105 °C |
Service temperature | up to 70 – 80 °C |
Specific values depend on the manufacturer and the material grade.
Melt flow (MFI)
The melt flow index is chosen depending on the application:
- 2 – 6 g/10 min — sheets, profiles, extrusion
- 6 – 15 g/10 min — standard injection moulding
- 15 – 20 g/10 min and above — thin-walled products
High flowability ensures precise mould filling and good surface quality of the finished products.
Applications
- Transparent packaging
- Disposable tableware
- Containers and blister packaging
- Stationery
- Household appliance housings
- Advertising and decorative elements
- Laboratory containers
Advantages
- Excellent transparency
- High rigidity
- Good detail reproduction in moulding
- Cost-effectiveness
- Easy processing
