Description of the properties and technical characteristics of expanded polystyrene. Dimensions and characteristics of expanded polystyrene Expanded expanded polystyrene foam

Expanded polystyrene is so widely used in various industries and construction that each of us periodically encounters it in everyday life. We will tell you about the properties and scope of this material in our article.

What is Styrofoam?

Expanded polystyrene became a unique innovation at the end of the 20s of the last century; its production method was patented back in 1928 and has been modernized several times since then. The main advantage of expanded polystyrene over similar materials is the unique combination of low thermal conductivity (insulation properties) and relatively light weight.

Production is carried out by adding gas to the polymer mass of polystyrene, which, upon subsequent heating, significantly increases in volume, filling the entire mold. To create volume, a different gas can be used, depending on which grade of expanded polystyrene you want to end up with: for simple variations of expanded polystyrene, natural gas is used, and fire-resistant varieties of expanded polystyrene are filled with carbon dioxide.

Very often, non-specialists believe that the concepts of "expanded polystyrene" and "polystyrene" are synonymous, but this is not true. Polyfoam and expanded polystyrene have a common base, but differ significantly in characteristics. Here is a comparative list of their main differences:

• the density of the foam is very low, 10 kg per cubic meter, and the expanded polystyrene is much heavier - 40 kg per cubic meter;
• expanded polystyrene does not absorb steam and moisture,
• externally, expanded polystyrene is more homogeneous, and foam is familiar to us all from childhood by its ability to crumble into granules;
• foam has a lower cost, so it is often used as a heat-insulating material for external wall cladding for "economical" repairs;
• expanded polystyrene has good mechanical strength, does not crumble or crumble.

Polyfoam is made from polymer raw materials, which are treated with steam, resulting in bulk granules. This provides the notorious "airiness" of the material, but it also has the other side of the coin: the micropores increase in size so much that as a result the bond between the granules deteriorates and therefore the foam quickly loses its insulating properties under the influence of precipitation and moisture. Simply put, even a small child can break the foam sheet, bending it in half.

For expanded polystyrene, such fragility is not characteristic, since its microcells are initially closed, which ensures the moisture and vapor impermeability of the material. At the beginning of production, the granules melt under the influence of high temperatures, forming a uniform fluid mass, which is then filled with gas.

By itself, expanded polystyrene also comes in several different types:

Pressless expanded polystyrene is one of the most popular varieties. Moisture is first removed from polystyrene granules by drying, then foamed at a temperature of 80 ° C, after which they are again dried and then heated again. The resulting mixture is filled into a mold, where it is already self-compacting at the time of cooling. This type of expanded polystyrene is more fragile, but requires half as much isopentane for its production, due to which its cost is relatively low.

Extruded polystyrene foam is practically the same material as non-pressed; the main difference lies in the use of equipment such as an extruder, which compacts the liquid expanded polystyrene mass obtained at the exit of production.

Extruded polystyrene foam is also obtained by processing the final mass of polymer material, and is also a dense homogeneous mass. We can find this variety in any grocery store or supermarket - it is actively used for the manufacture of disposable packaging and tableware.

Extruded polystyrene foam more expensive, since the technology is more multi-stage: the gas-foamed mixture is subjected to additional pressing, which gives it special strength.

Properties and characteristics

The debate over whether or not there should be expanded polystyrene has not subsided for the past fifty years: supporters extol its technical properties to the skies, and advocates of "healthy ecology" advocate a complete and widespread ban on the use of this material on the basis of "exclusive revelations" that have flooded a serious and not really the press. However, neither one nor the other can do anything with the quantitative and qualitative characteristics of the material - here they are:

• Very low thermal conductivity, which provides a significant insulation effect. An ordinary insulating layer does not exceed 13-15 cm in thickness, and this thickness is enough to provide the same level of thermal insulation as a two-meter brick wall! Let's look at the numbers: the thermal conductivity of expanded polystyrene is 0.027 W / mK, while for concrete - 1.2 -1.5 W / mK, for wood - 0.1 - 0.2 W / mK, for brick - 0, 35 - 0.6 W / mK.
• Moisture resistance: even with prolonged exposure to moisture, the absorbency will not exceed 6% (for wood - from 20 to 70%), so you do not have to worry that the expanded polystyrene layer is deformed. Expanded polystyrene is durable: in laboratory studies it has been proven that a standard layer of insulation is able to withstand up to 60 cycles of temperature drops from -40 C to + 40 ° C - that is, at least fifty to sixty years of operation.
• Insensitivity to biological pests. Expanded polystyrene is an unattractive material for all types of fungi.
• Harmlessness. No matter what the newspaper ducks say, non-toxic components are used in the production of expanded polystyrene - as we already wrote above, all food packaging is made from different types of expanded polystyrene, which undergoes mandatory certification.

If we talk about the practical side of the issue, builders love expanded polystyrene for its low weight: firstly, these are low transportation costs, and secondly, special physical training is not required to insulate high facades of buildings.

Fire-resistant grades of material, when exposed to an open flame, tend to self-extinguish and melt, not spreading combustion. The spontaneous combustion temperature of expanded polystyrene is 490 ° C, which is almost two times higher than that of wood. Expanded polystyrene extinguishes if an open flame source does not act on it for at least 4-5 seconds; at the same time, very little heat energy is released, about seven times less than that of a tree. That is why expanded polystyrene does not support the fire site and is well used in suburban suburban construction.

For residents of typical apartment buildings, the property of sound insulation will be very relevant - at the same time, you will not have to greatly reduce the living space: a 3 cm thick expanded polystyrene layer is enough to reduce the noise penetration level by 25 dB, so you will not be afraid of either loud music or the noise of a neighbor's renovation.

The vapor permeability of the material is at a low level of 0.05 Mg / m * h * Pa, regardless of the degree of foaming and density of the grade - this property is often used for building houses in conditions of high humidity. When compared with other materials, the vapor permeability indicators are similar to those of a pine or oak log frame.

Expanded polystyrene is resistant to alcohols and ethers, but at the same time it is sensitive to solvents: therefore, it is better to paint the insulated surfaces after all installation work is completed.

If we draw a conclusion from all the above characteristics, then expanded polystyrene is very effective for solving many problems: from using it as food packaging to providing thermal and waterproofing of building facades. For what purposes this material can still be used, we will tell you below.

Application area

So, expanded polystyrene as insulation is used primarily for the following elements:

• Roofs;
• Floors;
• door and window openings;
• walls;
• water pipes.

More specifically, molded block polystyrene foam is used to insulate pipes, which allows easy access to it in case of damage to the pipe - it is enough to remove the desired section of the protective coating. Insulation extends the service life of pipes by 5-10 years, so the use of expanded polystyrene can be considered economically justified.

If we talk about the "global" application, then expanded polystyrene is actively used for laying transport routes, and also allows you to regulate the vertical load on the coating during the construction of high-rise buildings. And, of course, numerous options for "sandwich" panels also did not do without expanded polystyrene.

Thus, the scope of application of expanded polystyrene, especially considering its low cost, is practically unlimited. However, one should not forget about one of its operational drawbacks: due to the low density, it is impossible to leave the material open on the surface - it suffers from mechanical damage.

Myths and Disadvantages: True or False?

Nothing is perfect, and there is no such material that would be completely devoid of flaws. We decided to consider each of the possible "myths" about expanded polystyrene in a little more detail and find out whether it is true or not.

1. You can often find advertisements that claim that "Extruded expanded polystyrene is significantly superior to other varieties"... This is not the case: the difference in thermal conductivity between extruded and extruded polystyrene foam is practically not noticeable and amounts to 0.002 units, and the popular "extrusion plates for insulation" add up to 30-50 percent in cost due to their untwisting.
2. "The density of expanded polystyrene does not in any way affect its insulating properties"... Any specialist in the field of construction will tell you that this statement is fundamentally wrong: after all, the tighter the molecules adhere to each other, the higher the thermal conductivity becomes, and the more cold will penetrate into the room. Therefore, for insulation, it is necessary to use low-density expanded polystyrene plates, which cover the outside of the reinforcement
3. "Fire-resistant polystyrene foam does not burn and is harmless to the human body." Every building material under an open flame will burn, to one degree or another! It's just that the spontaneous combustion temperature of expanded polystyrene is higher than that of wood, and when it burns, it will emit significantly less thermal energy.
   "Fire-resistant" varieties do not literally correspond to their name: they do not stop the flame, but only reduce its effect. And carbon dioxide, which is used in the production of such materials, will be released into the atmosphere during reflow, along with other substances harmful to humans.
   You can often see a demonstrative experience: the base with a plate of insulation fixed on it is heated from the back side - while the expanded polystyrene begins to melt and deform, but does not burn. But from this it is impossible to draw a conclusion about its complete incombustibility: under an open flame, expanded polystyrene will burn!
4. "Fire retardants added to polystyrene foam are a real poison!"... Yes, not all flame retardants are the same: they can differ in composition and contain various components, ranging from formaldehydes, which are really dangerous for humans, to magnesium salts, which are safe for all living things. Recently, the preponderance among fire retardants has shifted strongly towards inorganic salts, which will not harm health.
5. "Polystyrene foam insulation materials do not provide heat." One simple truth should not be forgotten here: insulation does not generate heat, but prevents it from leaving the premises; and the amount of this heat depends on how successful the building heating system is.
6. "Expanded polystyrene is hazardous to health"... We have already said about this above: expanded polystyrene is made from certified materials, therefore it is absolutely safe for health - its widespread use in the food industry tells us just about this.

The heat insulator of expanded polystyrene is 98% composed of air in thin-walled cells of expanded polystyrene. Such a structure provides the insulation material with its excellent technical properties and the possibility of using it in various areas of domestic and industrial construction.

Features of production and types of expanded polystyrene

Most often, polystyrene is used for the manufacture of expanded polystyrene, although polychlorinated styrene, butadiene, polymonochloride styrene and acrylonitrile can also be used as raw materials. By foaming, a gas enters the material, providing polystyrene with lightness and other useful properties. For foaming, the most commonly used hydrocarbons are pentane, dichloromethane and petroleum ether.

For the production of standard insulation materials, air is used to fill cavities in polystyrene. For the manufacture of heaters, characterized by resistance to high temperatures and combustion, carbon dioxide is used. Various additional materials can also be used to create expanded polystyrene, for example, fire retardants, plasticizers and dyes.

The process of manufacturing a heat insulator itself begins with filling the styrene granules with gas and dissolving the mixture in the polymer mass. Further, the future material is heated with the steam of a low-boiling liquid, as a result of which the styrene granules increase in size, fill the entire space around them and sinter into a single product. After that, it remains only to cut the resulting material into plates of the desired size and they can be used in construction.

Styrofoam is sometimes confused with Styrofoam, but these materials are not at all the same thing. Unlike polystyrene foam, polystyrene foam is obtained as a result of extrusion - a procedure for melting polystyrene granules and binding them at the molecular level. In the process of manufacturing polystyrene, polystyrene granules are combined in the process of processing with dry steam.

Depending on the manufacturing method, there are three types of expanded polystyrene, each of which has its own unique properties. Three methods of making insulation:

1. 1. Pressless production. In the composition of such expanded polystyrene, there are many pores and granules of different sizes (5-10 mm). Such insulation has high moisture absorption characteristics. There are different brands of PBS on the market: S-15, S-25, etc. The number in the marking means the density of the material.
2. 2. Press production. When manufactured under a press, a material is obtained with hermetically sealed pores, which provide it with good thermal insulation qualities, high density and strength. It is marked with the letters PS.
3. 3. Extruding. Extruded polystyrene foam (EPS) has a similar structure to extruded materials, but differs in pores of a significantly smaller size (no more than 0.2 mm). This is the most commonly used insulation in construction, which comes in different densities. The density is indicated on the package (EPS 25, EPS 30, etc.).

There is also an autoclave and autoclave extrusion insulation. They are found only abroad and are rarely used in construction due to their very expensive production.

The main characteristics of expanded polystyrene

The properties of expanded polystyrene, its density and other technical characteristics directly depend on the production technology. To determine the performance of the material, you need to pay attention to the following parameters.

One of the advantages is environmental friendliness

Thermal conductivity. A characteristic that made expanded polystyrene a very popular insulation. Thanks to the gas bubbles in the structure, it allows you to maintain the temperature regime inside the premises. The thermal conductivity of the material is between 0.028 and 0.034 watts per meter per Kelvin. The higher the density of the insulation, the higher the thermal conductivity will be.

Water vapor permeability. The vapor permeability index for different brands of insulation ranges from 0.019 to 0.015 mg / (m · h · Pa). Vapor permeability is not zero, since the sheets of insulation are cut, which means that air can enter its structure through these cuts.

Moisture permeability. Expanded polystyrene practically does not allow moisture to pass through. When EPPS is immersed in water, it absorbs about 0.4% of moisture, while PBS can absorb up to 4% of water. The material is resistant to high humidity and is not damaged.

Strength. Expanded polystyrene is characterized by a strong bond between individual molecules, its bending strength ranges from 0.4 to 1 kg / cm 2.

Chemical resistance. The insulation does not react with mineral fertilizers, cement, soap, soda and other chemicals. Only powerful solvents, for example, acetone or turpentine, can damage it.

Resistant to sunlight. Ultraviolet rays have an extremely unfavorable effect on expanded polystyrene, they reduce its strength and elasticity, and over time completely destroy its structure.

Sound absorption. Insulation can only extinguish impact noise and only in the case of thick laying. Polystyrene does not dampen wave noises.

Biological stability. The insulation is not suitable for the growth of fungus and mold, but can be easily damaged by insects and rodents.

Ecological cleanliness. It does not have a negative impact on the environment only if it is protected from harmful influences. In the open air and when burning, it emits many harmful substances to humans, including methanol, benzene and toluene.

Resistant to combustion. Insulation is a highly flammable material and emits corrosive smoke when burning, therefore it requires high-quality protection.

Durability. Correct installation and use of the material ensures its long service life - from 30 years or more.

To ensure the durability and safety of the insulation, it must be properly protected by the cladding from any adverse effects.

Advantages and disadvantages of a heat insulator

Expanded polystyrene, like other materials, has positive and negative features that should be considered before purchasing and using it. All these features of a heat insulator directly depend on its structure and the technical means used in the production. Its most important positive quality is its low thermal conductivity. With its help, you can reliably and effectively insulate almost any structure with your own hands.

Its popularity is due to its resistance to high and low temperatures.

Its low weight also has a positive effect on the possibilities of using insulation. Lightweight heat insulator slabs are easy to transport and install, while they do not create a large load on the building structures of the facility. The material does not pass or absorb water, and therefore the insulation not only provides the building with the preservation of the internal microclimate, but also protects the walls of the house from the adverse effects of moisture.

The widespread use of the heat insulator is largely due to its resistance to high and low temperatures, it can easily withstand heating up to 80 degrees and is not damaged even by severe frosts. The material begins to soften and deteriorate only with prolonged exposure to temperatures above 90 degrees. The owners appreciate the material for its low cost. It is much cheaper than most other heat insulators on the market today.

Expanded polystyrene increases the energy efficiency of an insulated house. Immediately after the installation of the insulation, the cost of heating and air conditioning the building can be reduced several times.

This is where the advantages of the heat insulator end and the disadvantages begin, the main of which is its environmental insecurity. The material burns well at temperatures from 210 degrees (some brands can withstand temperatures up to 440 degrees). When burning, very dangerous substances are released into the air that can harm both the residents of the insulated house and the environment in general.

Expanded polystyrene is not resistant to the sun and many chemicals, it is quickly damaged and loses its useful technical characteristics. The softness and warmth of the material is liked not only by people, but also by pests, who can quite easily make holes and passages in the insulation. You can protect yourself from rodents and insects only through the use of special compounds that increase the cost of installing and operating a heat insulator.

Due to the low density, steam can enter the insulation and condense in the structure. When the temperature drops to zero and below, condensate can freeze and damage the structure of the heat insulator, as a result of which the thermal insulation of the whole house will decrease.

In general, expanded polystyrene allows you to provide a house with high-quality thermal insulation, but it itself needs constant protection from many adverse influences. If such protection is not taken care of in advance, the insulation will quickly lose its positive qualities and can cause many problems for the owners.

Last time we talked about the technique ... Today we will talk about extruded polystyrene foam: technical characteristics, dimensions, advantages and disadvantages of this material. Ego can be used almost everywhere where there are no high temperatures and the need for thermal insulation to pass steam. Due to the high cost of insulation, whenever possible, everyone is trying to use cheaper foam, and extruded only when technically necessary. For example, with internal insulation, when every centimeter is expensive, or for laying thermal insulation in the ground.

Types and technical characteristics of extruded polystyrene foam

Penoplex is carrot-colored.

Extruded polystyrene foam and its technical characteristics differ slightly from different manufacturers. In the domestic market, there are three brands that are sold the most:

• Penoplex;
• Technoplex;
• Ursa.

They are all similar, with the exception of some nuances. For example, graphite is added to Technoplex, thanks to which the material becomes more durable. Due to graphite, the insulation becomes gray, unlike Penoplex, which is carrot-colored, or Ursa, a pale beige shade. Let's consider each of the brands separately.

Do not expose extruded polystyrene foam to direct sunlight and solvent.

Penoplex is a domestic product that is used for civil and industrial construction. The line of insulation is presented in ten positions. Main characteristics:

• extruded polystyrene foam thickness: 2, 3, 4, 5, 6, 8, 10, 12 and 15 cm;
• sheet dimensions: 60x120 cm, 60x240 cm;
• thermal conductivity of extruded polystyrene foam 0.03-0.032 W / m * C;
• compressive strength 0.2-0.5 MPa;
• water absorption no more than 0.4%;
• flammability group G4.

There is also a wedge-shaped insulation that is used for pitched roofs. The slope can be 1.7%, 3.4% and 8.3%. Technoplex is produced in thicknesses of 3, 4, 5 and 10 cm, standard sheet sizes are 60x120 cm and 58x118 cm. The difference from Penoplex lies in the higher coefficient of thermal conductivity, it transmits heat better by 0.002 W / m * C. It absorbs moisture by 0.2% worse and, due to the graphite in its composition, is more compressive strength. Accordingly, the material shows itself better at or basement walls.

Ursa is an international company that also has representative offices in Russia. It is one of the leading manufacturers of building materials. Extruded polystyrene foam is produced in three types. General characteristics:

• thermal conductivity 0.032-0.034 W / m * C;
• compressive strength 0.25-0.5 MPa;
• moisture absorption 0.3%;
• flammability group G4, except for Ursa XPS N-III, which has a flammability group G3.

Extruded Ursa expanded polystyrene dimensions: thickness 3, 4, 5, 6, 8 and 10 cm, length and width for all standard 60x125 cm.

Application of extruded polystyrene foam

Technoplex is gray in color due to graphite.

Extruded polystyrene foam, according to reviews, can be used for any insulation work, the restrictions are related only to the temperature regime of operation. It cannot be used where the temperature exceeds 75 degrees. This is a versatile material that is not afraid of moisture or stress, it can be put directly into the ground. Extruded polystyrene foam with a density of 25 kg / m3. the cube can withstand much higher loads than regular foam with a higher density.

Often, the scope of this insulation is limited only by financial capabilities, that is, an estimate. The fact is that it is expensive and where there is no real need for improved technical characteristics, ordinary foam is used. Epps insulation is suitable for insulation:

• concrete and wood floor;
• walls of any material outside and inside;
• wells made of concrete rings;
• blind areas;
• open ground.

There are also limitations where extruded polystyrene foam cannot be used. The use of the material is impossible in the sun, since when IR rays hit it, it is destroyed. Even a thin layer of paint protects against ultraviolet radiation.

Disadvantages of extruded polystyrene foam

Ursa is a European brand in Russia.

Despite all the useful properties of extruded polystyrene foam, this material is not without its drawbacks. The first stumbling block is the price, which hits the pocket a lot. In addition to the financial component, there are also specific technical flaws:

• the material is on fire;
• when heated above 75 degrees, it begins to emit harmful substances;
• afraid of IR rays;
• despite the assurances of the manufacturers, mice still start in it.

In addition, like any polymer, extruded polystyrene foam (all types and brands) is destroyed when interacting with solvents. Sometimes this problem occurs when , which must be accompanied by the application of waterproofing. In this capacity, bitumen rolls usually act, which are attached to a prepared wall. Preparatory work involves the application of bitumen mastic, some types of which have a high solvent content.

The ability to retain water and steam can be credited to extruded polystyrene foam both as disadvantages and advantages, it all depends on the scope of application. For example, for wooden houses, this quality can cause mold and wood decay. As a result, there will be a musty smell in the house, fungus spores in the air and it will quickly collapse. The concept of an eco-friendly, breathable home is being fundamentally violated.

Which brand of extruded polystyrene foam is better

As you can see, the characteristics of extruded polystyrene foam are approximately the same. It is difficult to unequivocally determine which one is better among the manufacturers of extruded polystyrene foam, they are all equal. Therefore, you should not worry too much about this, it is better to pay more attention to density. Those in the know recommend taking insulation with a density of 35 kg / m. cube, but otherwise everything depends on finances.

Expanded polystyrene is a rather interesting material. The production method was patented back in 1928, and has been modernized many times since then. The main advantage is low thermal conductivity, and only then in light weight. Expanded polystyrene is widely used in various industries and construction, and each person, in one way or another, came across products from it in everyday life. In addition, expanded polystyrene, the price of products from which is at a low level, will be a good option if you want to insulate your home.

What is expanded polystyrene and how is it different from polystyrene?

Expanded polystyrene is produced by adding gas to the polystyrene polymer mass, which, upon subsequent heating, significantly increases in volume, filling the entire mold. Depending on the type of material, a different gas is used to create volume: for simple variations, natural gas, fire-resistant types of expanded polystyrene are filled with carbon dioxide.

Quite often, it is common for amateurs to call polystyrene foam and polystyrene foam the same material. However, this is not entirely true. They have a common basis, but the differences and characteristics are quite significant. If you do not go into long spatial reasoning, then the main distinguishing features are as follows:

• the density of the foam is significantly lower, 10 kg per m3, while the indicators of polystyrene foam are 40 kg per m3,
• expanded polystyrene does not absorb steam and moisture,
• the appearance is different. Polyfoam - has internal granules, polystyrene foam is more homogeneous,
• foam plastic is characterized by a lower cost, which is noticeable when it is used as a heat-insulating material for the outer cladding of the walls of a building,
• expanded polystyrene has the best mechanical strength.

Polyfoam is produced from polymer raw materials, which are treated with steam, as a result of which the volume of the granules increases significantly. But at the same time, this leads to the fact that the micropores also increase in size, as a result of which the bond between the granules deteriorates and gradually, when exposed to atmospheric precipitation and climatic conditions, this leads to the fact that the material weakens. Roughly speaking, if you break a sheet of polystyrene in half, a large number of granules are formed. This is not typical of expanded polystyrene, since initially it consists of closed cells, which ensure the moisture and vapor impermeability of the material. At the beginning of production, its granules under the influence of high temperatures melt, forming a uniform fluid mass, which is filled with gas.

The material itself also has several varieties:

• Extruded polystyrene foam is practically the same material as non-pressed, the difference is in the use of equipment such as an extruder, therefore, extruded and extruded polystyrene foam is often called the same material.
• Extrusion is also obtained by processing the final mass of polymer material, and is also a homogeneous mass. The variety is used for the manufacture of disposable packaging and tableware. Roughly speaking, meat products in supermarkets are packed in packaging made of extruded polystyrene foam.

• The press method of obtaining the material is more expensive, since it involves the subsequent pressing of the gas-foamed mixture. In this case, it acquires additional strength.
• Autoclave expanded polystyrene is rarely mentioned, and in fact, it is an extrusion type, in which the foaming and baking of the material is performed using an autoclave.
• Pressless is one of the most popular varieties. Moisture is first removed from the polystrirole granules by drying, then foamed at a temperature of 80 ° C, then dried again and then heated again. The resulting mixture is filled into a mold, where it is already self-compacting at the time of cooling. This type of expanded polystyrene is more fragile, but requires half as much isopetane for its production, which affects the final cost.

Expanded polystyrene, characteristics and properties

Expanded polystyrene is an ambiguous material: someone exalts its properties to the skies, someone, on the contrary, foaming at the mouth, demands an immediate and complete ban on its use on the basis of "exposing the works of one academician." True, the ubiquity of expanded polystyrene and its high popularity incline conclusions towards the fact that this material is really good and has the following advantages:

• Low thermal conductivity allows a significant insulation effect to be achieved. In fact, 11 cm of expanded polystyrene can provide the same thermal insulation as a silicate brick wall more than two meters thick. The thermal conductivity of the material is 0.027 W / mK, which is significantly lower than that of concrete or brick,
• Moisture resistance of the material. Even with prolonged exposure to moisture, the absorbency will be no more than 6%, so there is no need to fear deformation of the structure of expanded polystyrene.
• Expanded polystyrene is durable and can withstand up to 60 cycles of exposure to temperatures from -40 to + 40 ° C. Each cycle constitutes an estimated climatic year.
• Insensitivity to the formation of biological media. Expanded polystyrene will not become a breeding ground for fungi and mold.

• Harmlessness of the material. In its production, non-toxic components are used, therefore, products from expanded polystyrene are also used in the food industry. For example, for storing food.
• Due to its light weight, insulation of building facades with expanded polystyrene takes much less time and effort than using other means.
• Fire-resistant grades of material, when exposed to an open flame, tend to self-extinguish and melt, not spreading combustion. The spontaneous combustion temperature of expanded polystyrene is + 490 ° C, which is almost two times higher than that of wood. In the absence of exposure for more than four seconds to an open source of flame on the material, the expanded polystyrene extinguishes. The heat energy during combustion of the material is 7 times less than that of a tree. Therefore, expanded polystyrene is not able to support the fire site.
• Providing soundproofing. This quality is especially important for residents of standard apartments. A 3 cm layer of insulating material is sufficient to reduce noise penetration by 25 dB.
• The vapor permeability of the material is at a low level of 0.05 Mg / m * h * Pa, regardless of the degree of foaming and the density of the grade. In fact, the vapor permeability indicators are similar to the timber frame of pine or oak.
• Resistant to alcohols and ethers, but easily subject to destruction when solvents come into contact with the surface of the material.
• The tensile strength is at least 20 MPa.

As can be seen from the above, expanded polystyrene is an effective tool for solving many problems: from using some of its varieties as packaging to providing heat and waterproofing of building facades. In addition, the material is used for other purposes in construction, which will be discussed below.

Application area

Expanded polystyrene in construction is used primarily for insulating the following elements:

• water pipes,
• roofs,
• floors,
• door and window slopes,
• walls.

For example, the consumption of expanded polystyrene for pipe insulation is economically justified and reasonable due to its capabilities. Moreover, for these purposes, molded block polystyrene foam is used, which allows, in the event of a pipe damage, to easily access it by removing the desired section of the protective coating.

Expanded polystyrene is actively used in the construction of transport routes. It reduces the effect of vertical loading on the floor during construction of buildings. Distributed in production.

The scope of application of expanded polystyrene, the characteristics of which, combined with a low price, make it extremely attractive for use in any industry, is practically unlimited. The only thing that should be taken into account is that the material has a low density, therefore, it is susceptible to any mechanical damage.

Disadvantages of expanded polystyrene: an overview of the myths

In addition to the bouquet of advantages, there are also disadvantages. Moreover, a large number of various myths are associated with expanded polystyrene, which must be considered in more detail:

• Many manufacturers claim that extruded expanded polystyrene foam is significantly superior to other varieties, as evidence of which they often expose a table of comparative characteristics of this variety in comparison with ordinary foam. Nevertheless, the difference in thermal conductivity between extruded and extruded polystyrene foam is practically not noticeable and amounts to 0.002 units, at the same time, due to advertising, the cost of extrusion plates for insulation is higher.
• The maximum density of expanded polystyrene gives the same high performance when insulated. According to experts, such a statement has some discrepancies with reality, since the more closely the molecules adhere to each other, the higher the thermal conductivity becomes and it is easier for cold to penetrate the room. A way out of this situation will be the use of low-density expanded polystyrene plates, which must be covered with a reinforcing mesh and a protective layer of primer in order to increase their mechanical strength.

• Fire-resistant polystyrene foam is absolutely non-flammable and harmless to the human body. Any building material, when exposed to an open flame, will exhibit combustion properties, more or less. However, the spontaneous combustion temperature of expanded polystyrene is higher than that of wood, and in addition, it emits significantly less thermal energy during combustion. It is important to remember that fire-resistant varieties, despite the loud name, are by no means able to stop the flame, only to reduce its effect. Carbon dioxide, which is used in its production, will become a serious disadvantage of a fire-resistant grade compared to the usual one. As a result, when reflowing, the material will begin to emit a significantly large amount of harmful substances. Some sellers talk about incombustibility based on demonstrative experience: when the base with a plate of insulation fixed on it begins to warm up from the back side. When exposed to high temperatures, polystyrene foam begins to melt and deform, while there is no fire. However, as long as the flame is exposed to it, the material will continue to burn.
• Fire retardants added to polystyrene foam for its fire resistance are "in any case, pure poison." Another controversial statement. A fire retardant is a component containing substances in its structure that slow down the combustion process. They differ in composition and contain various components, ranging from formaldehydes, which are really dangerous for humans, to magnesium salts, which are quite environmentally friendly and safe. Recently, solutions based on inorganic salts have been increasingly used, so they are not capable of harming health. Fire retardants are often used to impregnate and apply a protective layer to wood to increase its fire resistance.
• Installation of polystyrene foam insulation materials is not able to provide heat. In fact, the task of the insulation is not to bring heat, but to keep it indoors. Roughly speaking, the use of insulating plates will significantly reduce the escape of heat outside the premises, thus, you will not have to heat the street at your own expense.
• "Expanded polystyrene is hazardous to health." Modern production allows you to create material from environmentally friendly components, so there is no threat to health. Moreover, the widespread use of products for storing semi-finished products and for use in everyday life speaks precisely of the safety of the material.

More often, problems arise when you want to buy expanded polystyrene of cheaper and lower quality varieties. Insulation plates made of such a material really have less strength and are able to begin to deform even at temperatures above 40 ° C. The main rule when using materials from expanded polystyrene in any industry will be to ensure quality and reliability, for which you have to pay. And then in the course of operation only advantages will appear.

Extruded polystyrene foam and polystyrene foam are some of the most popular thermal insulation materials on the market. These heaters, it would seem, at different prices, have similar technical characteristics, and it is sometimes very difficult to choose a suitable option for use.

In this article, we will figure out which is better - polystyrene or expanded polystyrene, and what is the significant difference between these materials. A comparison of their technical characteristics and operational properties will be made.

1 Material features

Many people are often surprised how such a difference in price between these two materials is justified, if they are as identical to each other as possible.

The problem is that although foam is sometimes called polystyrene foam, since it is also made by foaming from the same raw material - polystyrene, it is impossible to identify extruded polystyrene foam and polystyrene foam, since they have significant differences.

The differences between these materials are due to different production technologies. The transformation of the initial polystyrene raw material into foam plastic is performed by exposing the polystyrene to high temperature steam, at which the raw material foams, during which the polystyrene molecules increase in size and join together.

Extruded polystyrene foam is made using a completely different technology. During the production process, polystyrene raw materials are loaded into special equipment - an extruder, where it is heated until the polystyrene molecules completely lose bonds, as a result of which a homogeneous liquid melt is formed.

Further, the melt having a viscous consistency is passed under pressure through an extrusion head (hole of a given shape), as a result of which an article of the required shape with a homogeneous structure is formed from the melt.

Extruded polystyrene foam Technonikol (and we recommend it) is a monolithic interconnected molecule of expanded polystyrene, which is a single structure through which neither steam nor moisture penetrates, while in the foam polystyrene polymer molecules are simply interconnected.

The technology for the production of extruded polystyrene foam differs from the technology for the production of foam plastic in a much greater labor intensity and duration of the process, which determines the difference in price between these two materials.

The above differences in production technology cause a significant difference between the functional properties of these two materials. Let's consider them in more detail.

1.1 Thermal conductivity

Thermal conductivity is the main characteristic of any heat-insulating material, the lower the thermal conductivity, the more effective the insulation is, and the less material thickness is required for high-quality insulation.

The thermal conductivity of extruded polystyrene foam is 0.028 W / mk, the thermal conductivity of the foam is 0.039 W / mk. If he is not defective. To minimize the risk of purchasing a defective product, we recommend.

According to this characteristic, extruded polystyrene foam is better than both polystyrene and most insulation materials existing on the market in general.

1.2 Mechanical strength

As already mentioned, the structure of extruded polystyrene foam is monolithic, while the components of the foam are simply connected to each other.

This leads to a serious difference in the strength characteristics of the materials under consideration. Extruded polystyrene foam has resistance to bending in the range of 0.4-1 MPa, and the compressive strength of 0.25-0.5 MPa, while the foam plastic has these indicators in the range of 0.07-0.2 MPa and 0.05-0.2 MPa, respectively.

In practice, under severe mechanical stress, it crumbles into small balls of which it consists. Also, this material is very brittle, as it is sensitive to bending deformations.

Extruded polystyrene foam is able to withstand quite serious bearing loads due to deformation of the building, as a result of shrinkage, or seasonal temperature changes.

The density of extruded polystyrene foam usually ranges from 30 to 45 kg / m3, while the actual density of the foam is 15-35 kg.

According to the requirements of the quality standards of the Russian Federation, the actual density of the foam plastic may differ from the nominal density by 10 kg / m3, as a result of which the real density of the same PSB-S35 foam rarely exceeds 26 kg / m3.

1.3 Hydrophobicity

The ability to absorb water is an important characteristic of any thermal insulation material.

In high-quality heaters, this property should be minimized, since when moisture is accumulated, the heater is prone to loss of its thermal insulation characteristics, weight gain and, with constant stay in a humid environment, decay and destruction.

Extruded polystyrene foam has a closed cell structure, as a result of which the material has practically zero moisture absorption. Unless he is defective. Therefore, we recommend to avoid marriage.

When fully immersed in water for 24 hours, extruded polystyrene foam absorbs liquids no more than 0.2% of its volume, while this indicator does not actually increase with a longer stay of the material in water - when immersed for 30 days, expanded polystyrene absorbs 0.4% of its volume.

Due to structural differences in foam, this indicator is much worse - in 24 hours the material, when fully immersed, absorbs 2% of the volume, when immersed for 30 days - 4%.

Such a difference in performance is more than significant, especially if the insulation is used in difficult conditions in terms of humidity. When insulating the basement, foundation and facade, extruded polystyrene foam manifests itself much better.

1.4 Refractoriness

The flammability class of heat-insulating materials acquires serious importance when it is necessary to insulate objects, the design of which has multiple wooden elements - attic or roof.

Also, building codes and regulations prohibit internal thermal insulation of industrial premises with combustible materials, as this contradicts fire safety requirements.

In terms of flammability class, extruded polystyrene foam is no different from polystyrene. All products based on polystyrene belong to the flammability groups (depending on the impurities contained in the product):

• G2 (normally flammable) as;
• G3 (highly flammable materials).

To address this issue, manufacturers, both in the foam and in the extruded polystyrene foam, add a fire retardant - a substance thanks to which the insulation acquires the ability to self-extinguish.

Studies show that with a sufficient concentration of fire retardant, in the absence of direct contact with fire, these materials go out within four seconds.

1.5 Tendency to shrink

Shrinkage, like moisture absorption, is the main enemy of any insulation. When the material shrinks, gaps appear in the insulation structure, which significantly reduce the overall insulation efficiency.

One of the main problems of foam is precisely the tendency to shrink when heated. To a greater extent, deformation manifests itself when the product is heated, therefore, it is better not to use polystyrene for thermal insulation of underfloor heating systems, and when insulating the facade with foam, the insulation must be covered with white plaster that protects from UV rays.

With extruded polystyrene foam, things are much better, the material practically does not shrink under any operating conditions.

2 Conclusions

Considering all the above comparisons, the answer to the question: "Which is better, foam or expanded polystyrene" is quite obvious, the efficiency of thermal insulation with extruded polystyrene foam is an order of magnitude higher in almost all parameters.

To make sure of this fully, we will compare the main technical characteristics of these materials:

• Thermal conductivity, W / mk: Expanded polystyrene - 0.028; Polyfoam - 0.039, like y;
• Vapor permeability coefficient, mg / mchPa: Expanded polystyrene - 0.05; Polyfoam - 0.022;
• Density of the material, kg / m3: Expanded polystyrene - 30-45, Polyfoam - 15-35;
• The percentage of moisture absorption from the volume when immersed for 24 hours: Expanded polystyrene - 0.2; Polyfoam - 2;
• The percentage of moisture absorption from the volume when immersed for 30 days: Expanded polystyrene - 0.4; Polyfoam - 4;
• Resistance to static bending, MPa: Expanded polystyrene - 0.4-1; Polyfoam - 0.07-0.2;
• Compression resistance (at deformation by 10%), MPa: Expanded polystyrene - 0.025-0.5; Polyfoam - 0.05-0.2;
• Flammability class: Expanded polystyrene - G2, Polyfoam G2 (normally combustible).

The operating temperature range for both materials is -50 to +75 degrees. When the temperature exceeds the specified value, deformation of the material begins. The ignition temperature of extruded polystyrene foam is 450 degrees, foam is 310 degrees.

If you choose what to use for home insulation, polystyrene or expanded polystyrene, then if the latter option fits into your budget, it is better to give preference to him.

Extruded polystyrene foam is an excellent option for thermal insulation of facades, foundations, floors, roofs and ceilings. A house insulated with expanded polystyrene will be an order of magnitude warmer than in a house insulated with expanded polystyrene. Best of all, or.

If your finances are limited, then use polystyrene foam, it certainly does not reach the technical characteristics of extruded polystyrene foam, however, among inexpensive insulation materials, this is the best choice.

2.1 Overview of the features of extruded polystyrene foam (video)