Polystyrene – PS
Application: Approx.. 10% of all thermoplastics is constituted by PS. Used extensively for mass manufactured items, due to the low price. Used electrical goods, medical articles, drikkebægre, packagings, household goods
PS plates are used in a very large extent for shaping the parts for the advertising industry, for signs, enclosures and the like, and the electron- and machine parts. As clear material finds PS apply to screens, attachment windows and picture framing. Toy, packaging, disposable cups, office supplies, inserts for drawers. PS included often in admixture with other materials, thermoplastic materials, due to the appearance and good mechanical properties.
Celleplast ( foam ) produced include. expandable polystyrene of both hard and soft foam. The cell structure formed by foaming a special, where an added propellant ensures foaming. The process enables the production of workpieces with very different densities and hardness. EPS is the abbreviation for Expanded Polystyrene. EPS raw appearance and texture is like sugar, and consists of approximately. 94% polystyrene and 6% pentane. Pentane is a propellant, which occur in nature and which do not affect the ozone layer or other environmental hazards,.
The raw material is expanded with water vapor to the desired density, then formed into aluminum molds with additional supply of water vapor. The finished EPS topics contain up to 98% air and 2% polystyrene and thus have a low weight.
A known commercial name is Flamingo with a thermal conductivity of about. lamp 0,041 W / mC.
EPS foam used for packaging and insulation.
Polystyrene is also included as a component in a kind of rubber called poly(styrene-butadiene-styrene), or SBS rubber. It’s a tough durable rubber used bla. a. for shoe soles and tires.
blow molding: Very used for bottles and containers.
Bending: PS is suitable for bending of heating wire / infrared heater at smaller thicknesses. PS plates may of course also varmbukkes by heating with heat gun el. or similar. The PS plate is heated, until it softens, and then be bent over an edge, a tube or otherwise, that has the desired shape. The plate is held in this position, until it has cooled. Bending with welding bucks sword at greater thicknesses.
Features mechanical: Hard and notch sensitive. The material is so rigid, that it keeps the strength blødgøringsområdet stable up to about the glass transition temperature. There is little tendency to creep (cold flow), but the allowable elongation at the tensile
very low – 0,4%. If this is exceeded, there will be stress cracks.
Styrenakrylnitril SAN copolymer is one of the thermoplastic materials with the greatest
rigidity. PS can be modified for good toughness (part of the ABS).
Features electric: In general, good electrical insulation properties. Dielectric values correspond almost to the PE’s, and they are nearly frequency independent.
PS should not be used with corona plants , resulting in creep voltage , as the surface over time changed.
extrusion: Widely used
Colors: White black div. colors.
Physiological properties: PS is used in the food, and there are both German and US rules, which the addition-position- and blending substances that may be used.
Trade names: Metzo® plastics PS, Vikureen®, Senosan®
History: Styrene has been known since 1831, where the French Kemist Bonastre distilled it from wood rosin. I 1839 styrene was polymerized by another French Kemist Simon Berthelot when exposed to sunlight. The styrene was prepared synthetically 1869. The German Hermann Staudinger published in 1922 that there was a plastic polymer, and continued his research which brought Hermann Staudinger Nobel Prize in 1953. Actual production started in England in the 1930s by BASF. Dow Chemical Co. started in 1937 produktion i USA. In Denmark, about. 700.000 ton om året .
Identification fire test: Burns with a sooting, orange yellow flame. Smells “sødt sweet”. Styrol monomer (do not self-extinguishing). But can be added flame retardants.
Category: amorphous material, stift med code lysgennemgang. Special grades may be semi-crystalline.
Chemical resistance: PS should be used with caution when in contact with solvents PS is resistant to many mineral acids (not oxidising), base, Self alcohol and is fairly resistant to aging. SAN is resistant to solvents such as gasoline and, moreover, oils and flavors.
PS and PS-HI is not resistant to most organic solvents.
Chemical structure: Plastic Gruppe with 3 types: GPPS polystyrene glasklar. – HIPS impact polystyrene. -EPS polystyrene ekspanderbar. as polyethylene, but with a benzene ring in place of one of the hydrogen atoms
Polystyrene is a vinyl-polymer. Density: 1,05 g/cm3
delivery semi: sheets – welding wire
Bonding: Adhesion can be by a weak solution of the adhesive surfaces, and after a certain afdampningstid compressed surfaces in about. 10 minutes. Fugen do not expose to any particular impact in 2 day. There may be used toluene, acetone, of methylene chloride and others. PS can be bonded to other materials by use of the contact adhesive and two- component.
Environment: In preparing, processing and disposal of polystyrene is a risk of the release of styrene and styrene oxide. These substances are considered to be carcinogenic. Polystyrene is used at high concentrations, suspected of being harmful to the ability to have children. On combustion or decomposition of water and CO2.
Optical properties: PS (GPPS) allow approximately. 90 % light pasage of visible light which is almost as good as acrylic. Addition of butadiene often gives the material a brownish color. HIPS is not transparent.
Surface treatment: It is possible to use various printing methods on PS, eg. Dry-offset, gravure and silkscreen, and it is possible to paint PS.
Assembly (mechanical): Caution with screws, blind rivets, and the like, which expose the material to great local tensions. Apply to click joints.
Injection molding: Widely used
Cutting: Semi-finished products of PS may well processed, but when PS is quite brittle, should be avoided, the tool cutting angles are sharp. It is important, the tool is sharp cooling with air or water.
Welding: Heat Mirror, varmluftsvejsning or ultralydssvejsning.
Thermal Properties: Scope under normal use between -40 and + 70 ° C.
It is above the glass transition temperature of about. 95° C very easy to shape and less temperature sensitive than PVC.
SAN copolymers and other, eg. MSA, can be used at higher temperature.
UV- Stability:UV radiation most advanced types PS. However, there are fair-weather types. PS types are very sensitive to stress corrosion cracking.
Thermoforming (Termoformning): PS is suitable for thermoforming. The material shall have a temperature of about. 120° C during forming. If the plate is too cold during forming, will result in internal stresses, which can result in stress cracking.
Density: 1,04 – 1,09