The initial form of expanded polystyrene is granules. They can be used to form products - plate, sheet, film - or applied as they are. Polystyrene foam granules are very light, flowable, small in size and have excellent thermal insulation properties.
Features and properties of expanded polystyrene granules
The raw material for the granules is styrene and its copolymers. The material itself is also a heat insulator, but not so outstanding. But if you saturate the polymer melt with gas and add a blowing agent, the polystyrene particles expand in volume, fill with air and form light granules that are not connected to each other.
The particles have a regular spherical shape. Sizes range from 1 to 8 mm. Small particles are used for stuffing toys, large ones for thermal insulation. The surface of the granules is smooth and firm. They weakly adhere to each other and in the volume have such a property as fluidity.
Granules can be obtained in another way. Solid expanded polystyrene is crushed to the original particles. In this case, part of the granules is destroyed, part is deformed. The resulting material is called crushed or crushed. Its characteristics are worse: if the integrity of the sphere is violated, the material absorbs water more strongly, contains less air, therefore it conserves heat worse.
Granular polystyrene foam, having all the qualities of a slab, has some features. They are associated with the flowability of the material:
- Soundproofing properties - there are no rigid bonds between the particles, the material cannot reflect sound, since it has an unstable structure. In addition, with free filling, air cavities of different sizes and shapes remain between the granules, which also contributes to the absorption of noise.
- Spheres filled with gas are elastic. Under mechanical action, they change their shape and restore it after the disappearance of the load.
- Loose polystyrene foam can take any shape, change it under pressure and restore it. This property is widely used in furniture making. Granular lightweight polystyrene foam is used for stuffing pillows, chairs, armchairs, and for the manufacture of frameless furniture.
- The density of the granules coincides with the density of the tile material obtained from them. The pattern is the same: the higher the density, the heavier the material, the stronger it is and the less it absorbs moisture. However, with an increase in density, the thermal insulation qualities decrease, therefore, too strong polystyrene is not produced.
Another indicator of granular polystyrene foam is the bulk density, from 8 to 40 kg / cubic meter. The smaller the granules and the denser they are, the higher this parameter.
Advantages and disadvantages
Granular expanded polystyrene has the advantages of the actual polymer and the structure of the mixture. The most important are the following:
- Polystyrene beads contain numerous air-filled pores. In terms of thermal insulation, the material exceeds that of concrete 30 times, hollow clay brick - 7 times. Since the granules have a spherical shape, they do not fit tightly to each other - cavities filled with air are also formed between the particles themselves. Polystyrene granules increase thermal insulation properties even when added to concrete.
- The polymer is not susceptible to mold and mildew.For rodents, he is also not of interest.
- Granular polystyrene foam is chemically inert, does not degrade under the influence of household chemicals.
- The shell of the granules is quite dense, they do not swell and do not absorb water. Loose polystyrene foam dries out when not too much wetted with water.
- Expanded polystyrene in round granules exhibits higher sound insulation properties.
- Unlike plate expanded polystyrene, bulk polystyrene allows air to pass through. Such a heat insulator "breathes" and does not provoke moisture condensation.
- The heat insulator retains its characteristics in the range from -80 to +75 C.
- 1 cubic meter m. crumbs weigh from 15 to 30 kg. Thermal insulation does not load walls or foundations.
- Polystyrene foam insulation lasts up to 80 years.
- Foam plastic chips are much cheaper than a plate heat insulator.
The disadvantages of polystyrene are inherent in all organic polymeric materials:
- The polymer is flammable, therefore it may only be used for external insulation or as a filler inside walls. Self-extinguishing material is also used for internal work: here the polymer dies out if it is removed from the combustion site.
- When burning, expanded polystyrene releases toxic substances. This is dangerous.
Granular polystyrene foam is produced in different densities. Strength, thermal insulation properties depend on this indicator.
Forms of issue
The initial raw material is polystyrene, it has a low density, within 1060 kg / cubic meter. However, the foamed version has an even lower density, so it is used mainly for insulation. It is offered in 2 forms.
In bulk
By treating the polymer with a gas and a blowing agent, spherical particles with a very low density are obtained. The granules are cooled and dried and then packed in bags. The particles are divided into fractions according to their size. For different purposes, granules of different diameters are required.
In molded products
It is based on the same polystyrene in round granules. The finished particles are not dried, but transferred to a mold, where they are sintered under the influence of temperature or temperature and pressure, forming a single whole. At the same time, the cellular structure is preserved.
This option is more convenient with external thermal insulation. Also, complex shapes can be cut from the plates to insulate any structures.
Application area
Granular polystyrene foam is used in a variety of areas:
- Thermal insulation - most often the granules are poured into the cavities between the walls. They also insulate the foundation, floors, attics.
- In the manufacture of expanded polystyrene concrete, foam crumbs are added to the concrete solution. Such material retains heat better.
- During the construction of pontoons, the cavities are filled with polystyrene chips.
- In wastewater treatment plants, granules act as an absorbent and purify liquids.
- Particles are used as filler for frame and frameless furniture.
- The material is also used in the field of design. Artificial snow is made from the crumb.
For internal thermal insulation work, only self-extinguishing polystyrene foam may be used.
Popular manufacturers
Granular polystyrene foam is offered by many manufacturers:
- LLC "Energoprommashina" from Yekaterinburg - produces a variety of brands of polystyrene. Price for 1 cubic meter m. from 1100 r.
- The company "Supply Logistics Construction" offers expanded polystyrene, packaged in packages of 0.6 cubic meters. m. for 830 p.
- Zavod Plastrom LLC produces self-extinguishing foam for 2000 rubles. for 1 cubic meter m.
- LLC "Teply Dom" in Orenburg produces crushed material for 1100 rubles. for 1 cubic meter m.
It is not difficult to acquire material. Its cost is slightly higher in large cities. More significantly, the price is affected by the brand, density, fraction, processing with fire retardants.
