Polystyrene (PS) is a synthetic aromatic hydrocarbon polymer synthesized by free radical polymerization of styrene monomer. Polystyrene applications include a wide range of products, from toys to packaging materials to refrigerator liners. Due to its versatility, it is one of the most widely used plastics. Polystyrene is available as solid plastic, rigid foam, and polystyrene films
Types of Polystyrene
1. Solid Plastic
- General Purpose Polystyrene(GPPS)
- High impact Polystyrene(HIPS)
2. Foam
- Expanded Polystyrene(EPS)
- Extruded Polystyrene(XPS)
3. Films
- Oriented polystyrene(OPS)
To know more about Polystyrene applications, let us understand the properties of various types of Polystyrene.
General Purpose Polystyrene
It’s a homopolymer (contains a single monomer) made from styrene, which is also known as a crystal clear polymer.
Properties
- Amorphous, colorless, and transparent
- Hard
- Brittle with low-impact strength
- Easy processing
Applications
It’s a cost-effective and easy-to-process resin and has a variety of applications. Its transparency makes it a popular food packaging material. It is also used to make toys, CD cases, etc.
High Impact Polystyrene
It is a copolymer and contains 5% to 10% butadiene rubber to improve the impact strength.
Properties
- Opaque, white in color
- High impact strength
- High dimensional stability
- Easy processing(thermoforming)
Applications
Its thermoforming ability and high impact strength make it ideal for refrigerator liners, toilet seats, tanks, and disposables. Provides excellent aesthetics as it can be painted. It is used for food packaging also, and Yogurt cups are a fine example.
Polystyrene foams
Polystyrene Foam is made by adding blowing agents. Polystyrene foams are 95-98% air and 5-2% PS. Polystyrene foams exhibit good thermal insulation properties as the voids are filled with air. Due to very low thermal conductivity, PS foams have a wide range of applications in construction and architectural models. By adding suitable additives, their properties can be altered depending on their uses. With the incorporation of graphite Grey, polystyrene foam is made, which exhibits superior insulation properties. With good damping properties, they are applied widely in the packaging industry as well.
Expanded polystyrene (EPS)
Polystyrene synthesized by suspension polymerization of styrene monomer is then impregnated with a blowing agent, usually pentane, to produce expanded polystyrene. It’s a closed-cell, white foam with an average density of 11 to 32 kg/m3.
Expanded Polystyrene Properties
- Rigid and tough
- Lightweight
- Low thermal conductivity
- Low moisture absorption
- Excellent cushioning properties
- The maximum operating temperature is around 80 °C
- Chemical inertness similar to Polystyrene
- High compressive strength
- Excellent dimensional stability
EPS can be molded by two different processes
- Block molding- produces large blocks, which can then be cut using hot wires into desired shapes or sheets.
- Shape molding- produces products that have custom-designed specifications.
Applications In Packaging
With good damping properties and lightweight, it is the best suitable product for packaging.
Food Packaging
Its insulation properties help in maintaining the freshness of food and other perishable items for a longer time. It has fungal and bacterial resistance. It is used as food service containers.
Industry Packaging
From delicate medical components to electronic components, anything can be packaged and shipped using EPS foams. EPS foam disposable cooler box plays a vital role in transit.
In Automotives
Its lightweight, energy absorption property, durability, and mouldability paved the way for extensive uses in automobiles. EPS foams are used under seat cushions, in dashboards, door panels, behind bumpers, etc. With high-impact absorption, it provides safety to passengers. The lightweight structure enhances fuel efficiency. Easy mouldability encourages designers to come up with elegant, comfortable as well as cost-effective fashion.
It’s used as Shock absorbing liner in helmets
In building and construction
EPS provides structural integrity and design flexibility.
With excellent thermal insulation properties, EPS sheets are well used as panels in buildings. Structural Insulated Panels(SIP) are used in buildings for roofing, exterior walls, ceilings, and flooring. It has excellent aesthetics and can be used for decorative purposes too.
Insulating Concrete Forms(ICF) are becoming extremely popular in the construction business as it is beautiful, safer, and last longer. The acoustic insulation property of EPS foams provides a calm and peaceful interior space.
EPS foams are available with various compressive strengths to withstand the load.
Additives like Flame retardants can be added for suitable applications.
Extruded polystyrene (XPS)
XPS has a different manufacturing process. It is made in a continuous extrusion process after adding blowing agents and additives to polystyrene and extruded into sheets. It is also a closed-cell rigid foam like EPS.
XPS Properties
- Rigid and tougher
- Lightweight
- Low thermal conductivity
- Very low moisture absorption
- Higher stiffness
- More resistant to water vapor than EPS
- Chemical inertness similar to Polystyrene
- Higher compressive strength than EPS
- Improved surface roughness
Applications
- XPS has similar applications as that of EPS. It can be used as an alternative to corrugated cardboard. They are widely used in crafts and model building.
- It is an ideal insulation material for houses and can be used on roofs, concrete floors. It is well suited for commercial buildings too.
- It provides cold storage solutions and is used in cool rooms and refrigerators.
- Extruded Polystyrene foam suppliers in UAE and worldwide have come up with various innovations in the product to meet customer needs.
Oriented polystyrene(OPS)
Extruded PS film can be stretched to produce oriented polystyrene. With increased stiffness and reduced haziness, the visibility is enhanced, enabling the customer to view the enclosed product clearly.
It is cheaper to produce than other clear plastics such as HIPS, polypropylene (PP), and (PET). It is less hazy than PP or HIPS. Though it is quite brittle compared to PP films, its cost-effective production makes it a better choice for products that require low crack resistance.
In conclusion, the different type of Polystyrene, its properties, and numerous applications makes it one of the most versatile polymer.
