Basic properties of polystyrene and its films

Polystyrene is colorless, odorless, odorless, non-toxic, has high transparency and surface gloss (its refractive index is 1.59%-1.60%), has high surface hardness and rigidity, colorability and oriented stretchability. it is good. It has high chemical stability, acid resistance and alkali resistance. At room temperature, it can be dissolved in organic solvents such as aromatic hydrocarbons, chlorinated hydrocarbons, esters and esters. Therefore, polystyrene resin can be dissolved in an organic solvent to form an adhesive and adhere to a polystyrene film. Polystyrene is brittle, poor impact, hot water resistance and oil resistance.
Polystyrene is resistant to gamma rays (sterilization by y-ray irradiation of the container without affecting its performance). Gas permeation
Medium rate of over-rate and high water vapor transmission rate. When the temperature is lower than 0 ° C, the moisture permeability is significantly reduced, which is very suitable for the packaging of low temperature foods. Its high aroma barrier properties prevent the escape of volatile oils and fragrances. Polystyrene is easily degraded by nitrogen and ultrasonic waves.
Polystyrene has low mechanical properties and is usually modified by blending and copolymerization methods. Commercial polystyrene includes general-purpose polystyrene (GPPS or transparent polystyrene), high impact polystyrene (HIPS), styrenic copolymers, styrenic alloys, and the like.
The modified polystyrene can be prepared by kneading with synthetic rubber (such as butadiene rubber or styrene-butadiene rubber); or the polybutadiene rubber can be dissolved in the styrene monomer before bulk polymerization. The polymerization is carried out again. Blend modified polystyrene, commonly referred to as high impact polystyrene, is a milky white opaque particle. It has high impact properties, electrical insulation properties and chemical properties, but its rigidity (flexural modulus), hardness and heat resistance are lower than ordinary polystyrene.
The styrene alloys obtained by the blending modification method mainly include polystyrene and polyphenylene ether alloys, and PPO/PS, PC/PS and the like.