Scientific name

Polystyrene

Monomer

Styrene - a colorless liquid synthesized from petroleum.

Colour

Polystyrene is a transparent, glass like material with a specific gravity of 1.05, which is basically the same as water. It is rigid and brittle, and when struck, it emits a metallic "ding dang" sound, with a clear and crisp sound, commonly known as "sound glue". Non toxic and odorless. Products produced by pure PS will immediately shatter when they fall to the ground and make a crisp sound.

Due to its good fluidity, high decomposition temperature, and stable melting density, PS has become an indicator parameter for measuring plasticization efficiency in injection molding machines. The injection molding machines in various countries around the world use PS to calibrate their capacity.

Combustion characteristics

Flammable, can continue to burn after leaving the flame, with a golden color at the top of the flame. When burning, it softens and foams, without any liquid dripping, and emits a thick black column of smoke. At the same time, it emits a "sweet aroma" of styrene monomer.

Advantages

1. Polystyrene is resistant to acids, alkalis, and low energy alcohols, and is softened by erosion from many hydrocarbons, ketones, and higher fatty acids. It is soluble in aromatic hydrocarbons.

2. Excellent electrical insulation, it is a good high-frequency insulation material with excellent arc resistance.

3. Polystyrene is a highly transparent material with a high surface gloss. Easy to print.

4. Polystyrene can freely color, is odorless, odorless, non-toxic, and does not cause bacterial growth.

Disadvantages

Poor mechanical performance, hard and brittle texture, easily susceptible to solvent corrosion and stress cracking. Low surface hardness, easy to scratch. Poor heat resistance and low thermal deformation temperature.

Injection molding performance

The typical melting point of PS is 173 ℃, and the decomposition temperature is 330 ℃. The adjustable range of injection temperature is relatively large. When injection molding, the general operating temperature is between 180 ℃ and 240 ℃. As it is an olefinic plastic, it does not absorb water and does not need to be dried during production. However, for product quality, it can be dried at 60 ℃ for 1 hour to discharge floating water. Polystyrene has a low melt viscosity and a high flow to length ratio, and generally does not require large gates or runners to fill the product. But PS is hard and brittle, so when designing products, it is important to avoid sharp corners and pay attention to the demolding angle, otherwise the product may crack. The product is prone to static electricity and the surface is prone to dust absorption. The shrinkage rate is 5 ‰. The overflow value is 0.03mm.