1. Introduction: What is Polystyrene Plastic?

PS (Polystyrene) is a general-purpose thermoplastic produced by the free radical polymerization of styrene monomers. It is one of the most widely used plastics in the world, and is widely used due to its transparency, rigidity, good processability and low cost.

When people mention "what is polystyrene plastic", they usually refer to two major types:

  ・GPPS (General Purpose Polystyrene) : Transparent, hard and brittle, used for packaging, containers, and transparent products.

  ・HIPS (High Impact Polystyrene) : By adding rubber to PS to increase its toughness, it is often used in the shells of household appliances, toys, and instrument components.

2. Main Performance Characteristics

Transparency

  ・GPPS has a high transparency, approaching that of glass. HIPS is semi-transparent or opaque.

Mechanical properties

  ・GPPS: High hardness but brittle, poor impact resistance

  ・HIPS: Significantly enhanced impact resistance and good toughness

Electrical performance

  ・It has good insulation properties and is often used in electrical appliance casings and components.

Processing performance

  ・It has good fluidity and is easy to be injection molded, extruded and thermoformed

  ・It can be expanded into EPS (expanded polystyrene), which is used for packaging and building insulation

Chemical stability

  ・Resistant to water and dilute acids and alkalis, but sensitive to organic solvents such as benzene and acetone.

Heat resistance performance

  ・The heat distortion temperature is approximately 70 to 100 degrees Celsius, making it unsuitable for high-temperature environments.

3. Common Application Fields

Packaging industry: food containers, disposable tableware, transparent packaging boxes

Construction: EPS foam for thermal insulation and cushioning

Household appliances: refrigerator linings, television casings, air conditioner panels (HIPS)

Daily necessities: stationery, toys, cosmetic containers

Medical: Disposable syringes, Petri dishes, reagent bottles

4. Comparison: PS vs Other Common Plastics

Table Notes:

  ・Ratings: ⭐ (lowest) → ⭐⭐⭐⭐⭐ (highest)

  ・PS Value Proposition: Best choice when clarity + low cost are critical, but less suitable where high heat or impact resistance is required.

  ・ABS, PP, and PET offer better toughness or heat stability for specific industries.

5. Processing Methods

PS particles can be made into products through the following processes:

  ・Injection molding: Toys, home appliance shells, daily necessities

  ・Extrusion molding: Sheets, films, pipes

  ・Foaming molding: EPS foam plastic, used for packaging and building insulation

6. Market Value of PS

As a bulk general-purpose plastic, the price of PS is much lower than that of engineering plastics.

  ・Unit price range: approximately 8 to 15 RMB/kg (depending on the brand and application)

  ・Representative suppliers: INEOS, TotalEnergies, Chi Mei of Taiwan, Sinopec, Yangzi BASF, etc

✨ In a nutshell: PS is a type of plastic with low cost, flexible processing, and wide application. It is the main material in the packaging, home appliance, and construction industries.

7. Common Modification Types

GPPS: High transparency, suitable for optical products and packaging

HIPS: Strong toughness, often used in household appliances, electronics and toys

EPS (Expanded grade PS) : Thermal insulation and heat preservation, cushioning packaging

Conductive PS: Add carbon black and conductive fibers for anti-static packaging

8. Market Trends and Prospects

Growth-driven

  ・The global packaging industry demand is stable

  ・The demand for building insulation materials (EPS) continues

  ・The demand for medical and disposable consumables has increased

Main challenges

  ・Environmental issue: Disposable PS products (lunch boxes, cups) are facing plastic restriction policies

  ・The recyclability and recycling rate are relatively low

Future trends

  ・The development of degradable and recyclable modified PS is accelerating

  ・High-transparency and high-strength PS are expanding in the medical and electronic fields

  ・The new foaming process promotes green and environmentally friendly applications

9. Summary

When we ask "what is polystyrene plastic", the answer is not merely "a common plastic", but a multi-faceted material covering fields such as packaging, home appliances, construction, and healthcare.

PS has long maintained its important position as a universal plastic worldwide due to its advantages of low cost, easy processing and diverse modification. In the future, with the strengthening of environmental protection and recycling trends, green PS materials will become a key direction for market development.