Polystyrene Specifications, Mechanical and Mold Properties

Polystyrene (PS) is a thermoplastic with amorphous structure that is designed for applications requiring excellent electrical and mechanical properties together and strong. Polystyrenes in generally are transparent, but available in various colors.

Now, polystyrene use in various application like household appliances, electrical parts, line printer parts, camera parts, rice cooker, refrigerator liners and others. Beside that polystyrene also use in toys parts, light diffusers, cutlery, electronic housings and cases. Then structural foam Polystyrene mouldings used for business machine housings, tools, cases and boxes. Others types of Polystyrene used for packaging. Foamed for food trays, egg boxes, and dishes.

Structure

The chemical makeup of polystyrene is a long chain hydrocarbon with every other carbon connected to a Phenyl group (the name given to the aromatic ring benzene, when bonded to complex carbon substituents)



POLYSTYRENE GRADES

they are
General Purpose Polystyrene (GPPS)
GPPS has excellent transparency, good water resistance, and a high dielectric strength. It is widely used for laminated electronic circuits, high frequency insulation sheet.
High Impact Polystyrene (HIPS)
HIPS has good dimensional strength, balanced properties of impact strength and heat resistance, is easily machined, and is relatively low cost.
Advantages
transparent but available in various color, low cost, rigid, , easy to mould and good dimensional stability. Good electrical properties, low dielectric loss. Excellent resistance to gamma radiation, It is available commercially in both pellet and sheet form. Good process ability including blow and vacuum molding, thermoforming, extrusion or compression molding, and machining. Good
Disadvantages
Brittle, poor chemical resistance especially to organics. Susceptible to UV degradation. Flammable, low impact strength, and poor weather ability

Chemical Properties
Glass transition temperature: 100oC.
Amorphous density at 25oC: 1.05 g/cm3.
Molecular weight of repeat unit: 104.1 g/mol.
Styrene Content 0.0500 - 55.0 %
Butadiene Content 60.0 - 78.0 %
Blowing Agent Content 4.50 - 6.80 %

Physical Properties
ASTM D570 Water Absorption, 24 hrs (%) GPPS 0.06; HIPS 0.01
ASTM D638 Tensile Strength (psi) GPPS 7,500; HIPS 4,000
ASTM D792 injection molding tool temperature (celcius) GPPS 20-60; HIPS 10-80
ASTM D792 injection molding pressure (kgf/cm2) GPPS 703-2110; HIPS 703-2110
ASTM D638 Tensile Elongation at Break (%) GPPS 47; HIPS 55
ASTM D785 Rockwell Hardness GPPS M60-70; HIPS M10-80
ASTM D792 Molding Shrinkage rate (%), GPPS 0,4-0,7; HIPS 0,4-0,7

Others Properties
Max. Operating Temp. (°C) 50
Water Absorption (%) 0.05
Oxygen Index (%) 18
Flammability UL94 HB
Volume Resistivity (log ohm.cm) 16
Dielectric Strength (MV/m) 20
Dissipation Factor 1kHz 0.0002
Dielectric Constant 1kHz 2.6