What is Polystyrene?
Polystyrene (PS) was first discovered in 1839 by Eduard Simon, an apothecary from Berlin, Germany. It is a versatile, rigid, and transparent thermoplastic polymer.
PS is widely utilized in various applications due to its:
- Excellent clarity
- Ease of processing
- Cost-effectiveness among other properties
Polystyrene shares some characteristics with other polymers such as polyethylene and polypropylene. But PS is less expensive, more rigid, and offers better clarity in its natural state. It has a glass transition temperature of about 100°C.
As PS shows excellent processability and is compatible with a variety of manufacturing techniques, it is widely used in diverse applications, including packaging, disposable cutlery, insulation, and laboratory ware. Some of the common applications are foam cups, food containers, plastic models, CD cases, and smoke detector housings.
What are the Advantages of Polystyrene?
PS is an ideal material well known for its versatile characteristics. It is widely used in the industry for its cost-effectiveness and ease of processing. The key properties of polystyrene include:
Optical properties
Transmittance – Polystyrene is a remarkably clear plastic that can transmit up to 88% of light, comparable to glass. Polystyrene sheets are offered in a variety of shades. These sheets can be tailored based on the requirements of the end-user.
Optical Nature – Due to its amorphous structure, polystyrene exhibits excellent optical properties. The refractive index of clear polystyrene is approximately 1.59.
Physical properties
Lightweight – This feature allows virtually unlimited possibilities for OEMs to design as compared with other materials. The property increases efficiency and makes the installation process easier. It also reduces overall transportation costs.
Protection from UV Radiations – Polystyrene can be designed to block ultraviolet radiation. It provides protection from harmful UV rays to some extent.
Chemical Resistance – Polystyrene exhibits good chemical resistance against diluted acids, aliphatic hydrocarbons, and alcohols. It shows moderate resistance against oils and greases. However, polystyrene is readily attacked by concentrated acids, alkalis, and aromatic hydrocarbons. Manufacturers recommend cleaning polystyrene using agents which do not affect its chemical nature. It is sensitive to abrasive alkaline cleaners.
Heat Resistance – Polystyrene has moderate heat resistance. It remains thermally stable up to 100°C. Further heat resistance can be improved by adding stabilizers without impacting material properties.
What are the Limitations of Polystyrene?
- Low impact strength
- Prone to brittleness
- Polystyrene has poor heat resistance
- Polystyrene exhibits limited chemical resistance
- Significant environmental impact due to non-biodegradability
What Are the Common Applications of Polystyrene?
Packaging Industry:
Good barrier properties, high strength, good surface finish, and low cost make Polystyrene ideal for several packaging applications. They perform well in rigid and foam containers for food, personal care, health, medical, and labware, household chemicals, and beauty aid products.
Consumer Goods:
Polystyrene is used in several household products and consumer goods applications, including disposable cutlery, CD and DVD cases, office supplies, and toys.
Appliances:
Polystyrene and their blends are used in appliances, such as refrigerators, air conditioners, coffee machines, food mixers, washing machines, hair dryers, steam irons, and water tanks. The use of Polystyrene allows shape freedom through its wide range of mechanical properties and enhances the robustness and visual appeal of a product.
Industrial Uses:
Polystyrene sheets are widely used in the industrial sector to produce insulation materials, display signs, and construction materials because of their properties like high impact resistance, ease of fabrication, and thermal insulation.
Clear PS Board VS Other Plastic Boards
Clear PS vs. Acrylic: Transparent PS boards offer a lower cost, making them a budget-friendly option for applications like framing and signage. However, acrylic boards surpass PS in terms of durability and UV resistance, making acrylic more suitable for outdoor use.
Clear PS vs. PC (Polycarbonate): PS boards are significantly less expensive and lighter than polycarbonate boards. However, PC boards outperform PS in terms of impact resistance, withstanding forces that would easily crack or break PS boards. PC’s higher temperature resistance also makes it more suitable for applications exposed to extreme heat.
Clear PS vs. PET (Polyethylene Terephthalate): Both materials offer good clarity, but PET has superior chemical resistance and is more commonly used in food packaging. PS, on the other hand, is more brittle but provides a clearer option for non-food items where lower cost is a priority.
Clear PS vs. PVC (Polyvinyl Chloride): PVC boards are more flexible and have a higher chemical resistance compared to PS boards. However, PS boards offer clearer visibility and are more rigid, making them a better choice for display purposes where flexibility is not required.
Is Polystyrene Toxic?
For a number of years, polystyrene is under scrutiny due to the:
- Presence of styrene monomers
- Use of additives such as flame retardants
Concerns about the negative impact of styrene have been raised at regular intervals in several regions. These monomers impact the environment and human health. However, on further investigations and studies, certain flame retardants are now confirmed safe for use.
Similarly, Europe has phased out the use of halogenated flame retardants in polystyrene compounds. They are classified as persistent, bioaccumulative, and dangerous for the environment. Their presence (chemical pollutants) causes issues in waste management strategies.