What is polystyrene

Polystyrene is a modern polymer that is strong, fairly rigid and durable. A colorless substance with a glass-like structure transmits about 90% of the visible spectrum rays. It is odorless and easy to paint. Many people are interested in what kind of material polystyrene is, the production and use of the polymer, as well as its properties and advantages.

Polystyrene: features and properties

Transparent plastic has improved optical properties, is suitable for the manufacture of lenses and optical prisms. Due to its lower fragility compared to glass, polystyrene lenses in glasses have almost completely replaced glass analogs. Optics made of plastic are cheaper than glass. The density of polystyrene is 1060 kg / m3. The material retains its original shape in the temperature range from -40 ° C to + 60 ° C. Other characteristics:

• Tensile strength – 350-600 kg / cm2.
• Compressive strength – 570-1300 kg / cm2.
• Bending strength – 800-1100 kg/cm2.

The material is resistant to the effects of salt solutions, oils – vegetable and mineral, alcohols, acetic acid. The structural formula of polystyrene assumes the presence of modifying additives that increase the plasticity and impact resistance.

Polystyrene: advantages and disadvantages

One of the advantages of the material is its suitability for multiple recycling. The widespread use of polystyrene is associated with the following advantages:

• affordable price;
• resistance to corrosion;
• resistance to the development of fungus and mold;
• water resistance;
• improved thermal insulation properties;
• simple processing technology.

One of the advantages is environmental friendliness. Most types of plastic have received food approval. The material is easy to cut on machines or with household tools – saws and knives. Ease of processing allows the manufacture of plastic furniture for street cafes. Among the disadvantages are increased fragility and fire hazard. Polystyrene products lose their consumer properties under the influence of ultraviolet rays, turn yellow and become covered with microcracks.

Polystyrenes: types

Polystyrene contains modifying additives that improve consumer properties. Thanks to additional components, the following types of material are obtained:

• general purpose;
• impact-resistant;
• foamed.

To achieve increased strength and resistance to impact loads, the polystyrene formula includes rubber monomers. Due to the rubber content, the material acquires greater flexibility, plasticity and impact strength. Sheets are made from it, which are then used to produce plastic products by thermal molding.

General-purpose plastic is characterized by increased tensile strength and resistance to temperature loads.

To obtain foamed material, components are added to the composition that provoke the formation of foam. Compared to ordinary polystyrene, foamed becomes lighter, acquires improved thermal insulation and sound insulation properties. Due to its ability to retain heat, expanded polystyrene has found wide application in construction. It is used to make materials for interior and exterior finishing, as well as for thermal insulation. Expanded polystyrene is used to make packaging for highly fragile goods:

• household appliances;
• computer equipment and mobile phones;
• glass, porcelain and ceramic tableware;
• tiles;
• door and window units.

The melting point of expanded polystyrene is 240-260°C. The material loses strength and is irreversibly deformed when heated above 80°C. Some ordinary polystyrenes are characterized by increased resistance to temperature loads, retaining consumer properties at temperatures up to 100°C. Due to the increase in the operating temperature range, the scope of application expands. Polystyrene is rarely used to make large-volume water storage tanks, which is due to its lower strength compared to polyethylene or polypropylene.

The material is used to produce plastic products of various shapes by pressing or injection molding at a temperature of 180-200°C. What is polystyrene used for:

• food containers, drink cups and other disposable tableware;
• insulation for electrical wires;
• office supplies;
• children’s toys.

The material is used to make transparent, rigid packaging, plastic dishes, household items and decor. Popular types of products are bread bins, mixer and blender bowls, advertising signs and plates, shower cabins and internal partitions. Greenhouses and diffusers for lighting fixtures are made of polystyrene.

Toys, food packaging and dishes made of the material are safe for human health. However, polystyrene is not suitable for the production of containers in which hot water and drinks are stored. At temperatures above 70 ° C, it begins to emit substances harmful to health.

Polystyrene: production technology

To understand what polystyrene is, it is worth knowing how it is made. The material is obtained from styrene during the polymerization reaction – the conversion of monomers into polymers. Styrene is a transparent liquid from the group of vinyl monomers. Styrene serves as a raw material for the production of various plastics, synthetic rubber and resins. Polystyrene is manufactured in different ways, which determines the characteristics of the finished product. The main polymerization technologies are suspension and bulk. Polymerization in suspension involves the presence of water and an activator. When the raw material is heated, granules are formed. The technology for producing a polymer in bulk involves the absence of water. As a result of the polymerization reaction, transparent granules of 3-5 mm in size are obtained, which are then used to produce plastic products for various purposes.

Polystyrenes: scope of application

Polystyrenes are widely in demand in various fields of activity – construction, automotive, food industries. The material is used to make floor, wall and ceiling coverings. It is used to make transparent rigid packaging for cookies, sweets, cakes, salads, greens, vegetables and fruits.

Spheres where polystyrene is used include the automotive industry. The material is used to make interior elements, seats, dashboards, bumpers and other body parts. Products made from the material have the ability to absorb shocks, which increases safety for the driver and passengers in the event of an accident. Equipping a car with plastic parts allows you to reduce weight, which has a positive effect on dynamic characteristics. At the same time, fuel costs are reduced.

Another area of ​​application is the manufacture of household appliances. Polystyrene is used to produce housings and parts of household appliances. The advantages of this solution are a reduction in the weight of devices and production costs, which is due to the affordable price of the material.

If we consider the physical properties of polystyrene, it is worth noting the ability to retain heat. Thanks to improved thermal insulation properties, the material increases the energy efficiency of refrigerators and freezers.

Polystyrene and polyethylene: comparison

Polystyrene and polyethylene are among the most popular plastics. Both materials are characterized by the following properties: low weight and affordable price. Polyethylene, in comparison with polystyrene, is distinguished by increased resistance to aggressive environments. Containers for storing chemicals – acids, alkalis, alcohols – are made of polyethylene.

A feature of polyethylene is its increased strength, which makes the material suitable for the manufacture of containers with a capacity of more than 10 thousand liters. Polyethylene containers are used to safely grow and transport fish, agricultural products, fertilizers, and industrial water. The chemical properties of polystyrene allow the material to be used to manufacture medical equipment and disposable consumables. The plastic is resistant to chemicals and can be repeatedly disinfected. Polystyrene is easier to mold than polyethylene, which allows the material to be used to create inexpensive products of complex geometric shapes. Polystyrene is cheaper, which makes it economically viable to buy products made from it.