Foamed polyethylene (polyethylene foam) - polyethylene subjected to foaming by hydrocarbons in the production process. The result is an elastic elastic web having a closed-cell structure of the cells. Available in rolls, sheets, in the form of shells and bundles. The material has been widely used in various industries, especially in construction , due to: high heat and sound insulating qualities, strength characteristics, ease of installation and relatively low cost. Crosslinked and non-crosslinked polyethylene foam is isolated according to the production method.
Content
Physico-mechanical properties
| Indicator | Crosslinked Polyethylene Foam | Non-cross-linked polyethylene foam |
|---|---|---|
| Density, kg / m3 | 25-200 | 20-50 |
| Combustibility group (GOST 30244-94) | G1-G4 | G2-G4 |
| Smoke generating group (GOST 12.1.044-89) | D3 | D3 |
| Water absorption by volume,% no more | one | 0.2 |
| Specific heat, W (m * degree C) | 1.8 | - |
| The coefficient of vapor permeability, mg (m * h * Pa) | 0.001 | 0.001 |
Polyethylene foam production
Currently, there are two types of polyethylene foam, obtained in different ways. They are conditionally divided into:
- crosslinked foams (designated as PPE - polyethylene foam)
- non-cross-linked foams (designated as NPE - non-cross-linked polyethylene foam)
Stitched Foam
Foamed polyethylene is produced on a complex technological line with step heating. Its output parameters are determined by the ratio of polyethylene and foaming and functional additives. Due to this, the PES sheet can be made with minimal deviations from the specified parameters (± 0.1 mm in thickness and ± 1 kg / m 3 in density). The material has a flat surface and a fine-meshed structure with a closed pore. Due to this, it is more resistant to irreversible damage under the action of high point loads than NPE. It is ecologically safe; tourist and sports mats are made from it. It has excellent performance properties. There are two types of cross-linked polyethylene foam:
- chemically crosslinked
- physically stitched
Article about Crosslinked Polyethylene Foam
Unstitched Foam
Obtained by foaming polyethylene with a propane-butane mixture or authorized freons. In the extruder under pressure, the melt and mixing of polyethylene with a blowing agent (usually a propane-butane mixture) occurs. When exiting the extruder by reducing external pressure, the gas expands, and thus a gas-filled bubble is obtained. Since the temperature drops sharply when exiting the extruder, the bubble foam that has left hardens and polyethylene foam forms. For a number of target characteristics (thermal conductivity, reduction in shock noise, sound absorption, vapor impermeability) is not inferior to PES. Due to the fact that NPE is 2.5-5 times cheaper than PPE, it is widely used as heat and sound insulation, lodgements, packaging, etc.
See also
- Construction Materials
- Thermal insulation
Literature
- Batrakov A. N., Ampleeva I. A., “Crosslinked and non-crosslinked foams, their similarities and differences”, Industrial and Civil Engineering 9/2005, Publishing House PGS, ISSN 0869-7019
- Prizhizhetsky S. I., Samsonenko A. V. “A new standard for the design of thermal insulation of equipment and pipelines.”, Industrial and Civil Engineering 12/2008, Publishing House “PGS”, ISSN 0869-7019
- I.V. Kuleshov, R.V. Torner, “Thermal insulation from foamed polymers”, Moscow Stroyizdat 1987 - 144 p.
- A. I. Larionov, G. N. Matyukhina, K. A. Chernova, “Polyethylene foam, its properties and applications”, Leningrad House of Scientific and Technical Propaganda, Leningrad, 1973, - 16 p.