Polyethylene – non-polar synthetic thermoplastic polymer belonging to the class of polyolefins. polymerization of ethylene product. White solid. It is produced in the form of low-density polyethylene (HDPE) produced by the suspension method polymerization of ethylene at low pressure, on complex organometallic catalysts in a slurry or gas phase by the polymerization of ethylene in the gaseous phase complex organometallic catalysts medium and high-density polyethylene (LDPE) produced under high pressure ethylene polymerization reactors or in tubular reactors with a stirrer radical type initiators. In addition, there are several subclasses polyethylene different from conventional higher performance. In particular, ultra high molecular weight polyethylene, linear low density polyethylene produced with metallocene catalysts, bimodal polyethylene.
Typically, the polyethylene produced in the form of stabilized granules of 2-5 mm in diameter in the form of painted and unpainted. But there is commercial production of polyethylene powder.

Average PE designation in the Russian market – PE, but can meet and other designations: PE (polyethylene), LDPE or HDPE or LDPE or PEBD or PELD (low density polyethylene, high density polyethylene), HDPE or LDPE or HDPE or PEHD (polyethylene high density, low-density polyethylene), LDPE or MDPE or PEMD (medium density polyethylene), ULDPE (ultra low density polyethylene), VLDPE (very low density polyethylene), LLDPE or LLDPE or PELLD (LLDPE), LMDPE (linear polyethylene of average density), HMWPE or PEHMW or VHMWPE (high molecular weight polyethylene). HMWHDPE (high molecular weight high density polyethylene), PEUHMW or UHMWPE (ultra high molecular weight polyethylene), UHMWHDPE (ultrahigh HDPE), PEX or XLPE (crosslinked polyethylene), PEC, or CPE (chlorinated polyethylene), EPE (expandable polyethylene), mLLDPE or MPE ( metallocene linear low density polyethylene).

Symbol suspension domestic low pressure polyethylene, consists of the name “polyethylene” material eight digits that characterize a particular brand and standard notation, whereby the polyethylene was made.
The first digit 2 indicates that the process is ethylene polymerization on complex organometallic catalysts at low pressure. The next two digits indicate the serial number of the base brand. The fourth digit indicates the degree of homogenization of polyethylene. Low density polyethylene is subjected to averaging cold mix, which is denoted by the numeral 0. The fifth digit defines the conditional density polyethylene Group:
6 – 0,931-0,939 g / cm3;
7 – 0,940-0,947 g / cm3;
8 – 0,948-0,959 g / cm3;
9 – 0,960-0,970 g / cm3.
When determining the density of the group taking the average value of the density of a given brand. The following figures are written by a dash to indicate a tenfold the average value of the melt flow index of this brand.
Example identification mark basic low pressure polyethylene slurry sequence number mark 10, the average cold mixing, the density of 0,948-0,959 g / cm3 and an average melt flow index of 7.5 g / 10 min:
PE 21008-075 GOST 16338-85.
Designation HDPE composition containing no colorant additive material consists of the name “polyethylene”, the first three digits denote the base mark compounding additives numbers written by dashes and standard notation, whereby the polyethylene was made.
Example identification slurry composition of low pressure polyethylene with a base mark 21008-075 additives according to the formulation 04:
Polyethylene 210-04 GOST 16338-85.
Example designate low-pressure gas-phase polyethylene composition brand 271 with additives according to the formulation 70:
Polyethylene 271-70 GOST 16338-85.
Designation of the composition of low-density polyethylene with the addition of dye consists of the name “polyethylene” material, the first three digits of the base brand, written by a dash numbers formulation additives (if any), written by a comma-separated names of color, three-digit number, indicating the recipe color, and marking standard , whereby the polyethylene was made.
Example for the base grade high-density polyethylene composition 210-04 21008-075 and based on it, painted in red color on the formula 101:
Polyethylene 210, red rec. 101 GOST 16338-85,
Polyethylene 210-04, red rec. 101 GOST 16338-85.

Basic brand slurry polyethylene of low pressure: 20108-001; 20208-002; 20308-005; 20408-007; 20508-007; 20608-012; 20708-016; 20808-024; 20908-040; 21008-075.

The basic brand of gas-phase polyethylene of low pressure: 271-70; 271-82; 271-83; 273-71; 273-73; 273-79; 273-80; 273-81; 276-73; 276-75; 276-83; 276-84; 276-85; 276-95; 277-73; 277-75; 277-83; 277-84; 277-85; 277-95.

Symbol domestic high pressure polyethylene consists of the name “polyethylene” eight numbers and designations grade standard, according to which polyethylene was made.
First digit – 1 indicates that ethylene polymerization takes place at high pressures in tubular reactors or reactors with mixing devices using radical type initiators.
The next two digits indicate the serial number of the base brand. The fourth digit indicates the degree of homogenization of polyethylene:
0 – no homogenization in the melt;
1 – homogenized in the melt.
The fifth digit conventionally defines a group of polyethylene density, g / cm3.
1 – 0,900-0,909
2 – 0,910-0,916
3 – 0,917-0,921
4 – 0,922-0,926
5 – 0,927-0,930
6 – 0,931-0,939
When determining the density of the group take its nominal value for a given brand.
The following figures are written by a dash to indicate a tenfold value of the melt flow index.
Example identification sequence number LDPE grade 15 without homogenization in the melt, a density of 0,917-0,921 g / cm3 and a nominal value of the melt flow index of 7 g / 10 min 1st grade:
PE 11503-070, Class 1, GOST 16337-77
Designation LDPE compositions here consists of material “polyethylene”, the first three digits denote the base mark compounding additives numbers written by a dash, color and staining formulation, type and designation of the standard, according to which polyethylene was made.
Example identification of high-density polyethylene composition of the base brand 10204-003 with additives according to the formulation 03, 1st grade:
Polyethylene 102-03, grade 1, GOST 16337-77
In the case of colored high-density polyethylene composition is added to the designation of color and three-digit number that represents the color formulation.
Example identification of high-density polyethylene composition of the base brand 10204-003, painted in pink on the formula 104, 1st grade:
Polyethylene 102, pink 104, Class 1, GOST 16337-77
The designation of a high density polyethylene intended for the manufacture of films for various purposes, products in contact with food, drinking water, medicines and cosmetics, toys, as well as polyethylene to be long-term storage, further indicate the relevant purpose.

Basic grade high density polyethylene produced in a reactor with a stirrer: 10204-003; 10604-007; 10703-020; 10803-020; 11304-040; 11503-070; 12003-200; 12103-200.

Basic brand low density polyethylene prepared in a tubular reactor type: 15003-002; 15303-003; 15503-004; 16305-005; 17603-006; 17504-006; 16005-008; 17703-010; 16603-011; 17803-015; 15803-020; 16204-020; 16405-020; 18003-030; 18103-035; 16904-040; 18203-055; 16803-070; 18303-120; 17403-200; 18404-200.

In the cable industry uses compositions based on LDPE (low density) and low pressure (high density) with stabilizers and other additives designed to overlay insulation covers and protective covers wire and cable extrusion.
Stamps polyethylene compositions for cable industry are established on the basis of basic grades of high density polyethylene 10204-003, 15303-003, 10703-020, 18003-030, 17803-015 and compounding additives 01, 02, 04, 09, 10, 93-97, 99, 100, 10703-020 brands and formulations 61 and low pressure polyethylene (slurry method), 20408-007, 20608-012, 20708-016, 20808-024 and compounding additives 07, 11, 12, 19, 57 high-density polyethylene ( gas phase method) based on the mark 271 and powder formulations of additives 70, 82, 83, 273 brand powder formulations of additives and 71, 81.
Key brands of polyethylene compositions for cable industry consists of the name “polyethylene” material, the first three digits denote polyethylene core brand, Room compounding additives, written by a dash, and the letter “K”, indicating the use of polyethylene compositions in the cable industry, and notation standard, whereby the polyethylene was made to the cable industry.
Example symbol cable industry for compositions based on high density polyethylene with a base mark 10204-003 additives according to the formulation 09:
Polyethylene 102-09K GOST 16336-77
Notation example compositions based on cable industry HDPE base brand 20408-007 additives according to the formulation 07:
Polyethylene 204-07K GOST 16336-77

When ordering polyethylene after the designation marks indicate grade. For polyethylene, intended for the manufacture of electrical products and articles in contact with foodstuffs, drinking water, cosmetics and medicines, toys, and the contacting of the contacting with the oral cavity, and for polyethylene, to be long-term storage, further indicate the appropriate destination.

But in the market there are other brands of polyethylene, as most producers work according to their own specifications, reflecting the development of the plastics industry, for which the standardization of the system does not always have time

Properties: Polyethylene – a plastic material with good dielectric properties. Impact-resistant, does not break, with little absorbency. Physiologically neutral, odorless. It has low vapor and gas permeability. Polyethylene does not react with any alkali concentration with solutions of any salt, carboxylic, concentrated hydrochloric and hydrofluoric acids. Resistant to alcohol, gasoline, water, vegetable juice, oil. It destroyed 50% nitric acid, as well as liquid and gaseous chlorine and fluorine. Insoluble in organic solvents and limited swells therein. Polyethylene racks by heating under vacuum and inert gas atmosphere. But it was degraded by heating the air already at 80 ° C. Resistant to low temperatures to -70 ° C.. Under the influence of solar radiation, particularly ultraviolet rays, subjected to photodegradation (used as a black light stabilizers, benzophenone derivatives). Practically harmless, because it is not released into the environment hazardous to human health.
Polyethylene is easily processed by all major plastic processing methods. Easy is modified. By chlorination, sulfonation, bromination, fluorination it is possible to give rubber-like properties to improve the heat resistance, chemical resistance. Copolymerization with other olefins, polar monomers improve cracking resistance, flexibility, transparency, adhesion characteristics. Blending with other polymers or copolymers to improve toughness and other physical properties.
Chemical, physical and performance properties of the polyethylene are dependent on the density and molecular weight of the polymer, and therefore different for different types of polyethylene. For example, LDPE (polyethylene of branched chain) is softer than the HDPE film thus HDPE dense and more rigid than high density polyethylene. Their tensile strength and compressive higher tear strength and lower impact, while permeability is 5-6 times lower than those of films of LDPE.
Ultrahigh molecular weight polyethylene with a molecular weight of over 1 000 000 has a higher strength qualities. The temperature range of its operation from -260 to +120 ° C. It has a low coefficient of friction, high abrasion resistance, crack resistance, chemical resistance to most corrosive environments.

Properties of HDPE in accordance with GOST 16338-85.
1. Density – 0,931-0,970 g / cm3.
2. Melting point – 125-132 ° C.
3. The Vicat softening temperature in air – 120-125 ° C.
4. Bulk density of granules – 0.5-0.6 g / cm3.
5. Bulk density of powder – 0.20-0.25 g / cm3.
6. Breaking bending stress -19,0-35,0 MPa
7. The tensile strength at the cut – 19,0-35,0 MPa.
8. Hardness Ball indentation under a given load – 48,0-54,0 MPa.
9. Specific surface resistance – 1014 ohms.
10. Volume resistivity – 1016-1017 ohm-cm.
11. Water absorption for 30 days – 0.03-0.04%.
12. Dielectric loss tangent at a frequency of 1010 Hz – 0,0002-0,0005.
13. The dielectric constant at a frequency of 1010 Hz – 2,32-2,36.
14. The specific heat at 20-25 ° C – 1680-1880 J / kg · ° C.
15. Thermal Conductivity – (41,8-44) 2.10 · V / (m · ° C).
16. The linear coefficient of thermal expansion – (1,7-2,0) · 10-41 / ° C.

Properties LDPE in accordance with GOST 16337-77.
1. Density – 0,900-0,939 g / cm3.
2. Melting point – 103-110 ° C.
3. Bulk density – 0.5-0.6 g / cm3.
4. Hardness Ball indentation under a given load – (1,66-2,25) · 105 Pa; 1.7-2.3 kg / cm2.
5. The shrinkage at molding – 1.0-3.5%.
6. Water absorption for 30 days – 0.020%.
7. Breaking bending stress – (117,6-196,07) · 105 Pa; 120-200 kg / cm2.
8. Strength – (137,2-166,6) · 105 Pa; 140-170 kg / cm2.
9. Volume resistivity – 1016-1017 ohm-cm.
10. The specific electrical surface resistance – 1015 ohms.
11. Brittleness temperature for polyethylene a melt flow index in g / 10 min
0.2-0.3 – no higher than minus 120 ° C,
0.6-1.0 – no higher than minus 110 ° C,
1.5-2.2 – no higher than minus 100 ° C,
3.5 – not higher than minus 80 ° C,
5.5 – not higher than minus 70 ° C,
7-8 – is not higher than minus 60 ° C,
12 – not higher than minus 55 ° C,
20 – not higher than minus 45 ° C.
12. Tensile modulus (secant) for density polyethylene in g / cm2
0,917-0,921 – (882,3-1274,5) · 105 Pa; 900-1300 kgf / cm2,
0,922-0,926 – (1372-1764,7) · 105 Pa; 1400-1800 kg / cm2,
0.928 – 2107.8 · 105 Pa; 2150 kgf / cm2.
13. Dielectric loss tangent at a frequency of 10,100 Hz – 0,0002-0,0005.
14. The dielectric constant at a frequency of 1010 Hz – 2,25-2,31.

Comparative analysis of the characteristics of HDPE and LDPE shows that HDPE, due to the higher density, has higher strength characteristics: heat resistance, rigidity and hardness, has a higher resistance to solvents than LDPE but less frost. Slightly worse than LDPE (due to catalyst residues), high-frequency electrical characteristics, but it does not restrict the use of LDPE as insulating material. Furthermore, the presence of the catalyst residues does not allow the use of HDPE in contact with food (requires washing of the catalyst). Due to tighter packing HDPE macromolecular permeability lower than that of LDPE is about 5-6 times. According to the chemical resistance of HDPE also exceeds LDPE (especially resistance to oils and fats). However, LDPE film more permeable to gases, and therefore unsuitable for packaging products sensitive to oxidation.

Preparation: In industry, polyethylene is produced by polymerizing ethylene at high (HDPE, LDPE) and low pressure (LDPE, HDPE).
Low density polyethylene (low density) is obtained by polymerizing ethylene at high pressure reactors or in tubular reactors with a stirrer radical type initiators.
Low density polyethylene produced without additives – basic brand or as their compositions and with stabilizers and other additives in the form of painted and unpainted.
Low-pressure polyethylene (high density) to give a slurry process polymerization of ethylene at low pressure, on complex organometallic catalysts in a slurry or gas phase by the polymerization of ethylene in the gaseous phase complex organometallic catalysts supported or polymerizing ethylene in solution in the presence of a titanium magnesium catalyst or CrO3 on silica.
Polyethylene obtained by the suspension method (slurry polyethylene) produced without additives (base mark) in the form of their compositions, stabilizers, dyes and other additives.
Polyethylene produced by a gas phase (gas phase polyethylene) produced in the form of compositions with stabilizers.
The polymerization process occurs at a high pressure radical-initiators are oxygen, peroxides such as lauroyl or benzoyl peroxide, or mixtures thereof.
In the production of LDPE, ethylene in a tubular reactor, mixed with the initiator, compressed by the compressor 25 MPa and heated to 70 ° C, is first fed into the first zone of the reactor, where it is heated to 180 ° C, and then a second, which is polymerized at 190-300 ° and a pressure of 130-250 MPa. The average residence time in the reactor ethylene 70-100 with the degree of conversion of 18-20% depending on the type of initiator and kolichestvava. Of polyethylene, unreacted ethylene is removed, the melt is cooled to 180-190 ° C and pelletized. Granules, chilled water to 60-70 ° C, dried in warm air and bagged.
Schematic diagram of the production of LDPE in an autoclave with stirring device differs from the production in a tubular reactor, in that the initiator is fed in paraffin oil special high pressure pump directly to the reactor. The process is carried out at 250 ° C and a pressure of 150 MPa. The average time of stay in the reactor ethylene – 30. The conversion rate – about 20%.
Product LDPE produce colored and uncolored, in granules of 2-5 mm in diameter.
The polymerization process occurs at low pressure by coordination-ionic mechanism.
Producing HDPE in a slurry comprising the steps of: forming a slurry of catalyst and activator solution is a combination of triethylaluminum and titanium derivatives; polymerizing ethylene at a temperature of 70-95 ° C and a pressure of 1,5-3,3 MPa; removing the solvent, drying and granulation polyethylene. The degree of conversion of ethylene – 98%. The concentration of polyethylene in suspension – 45%. A single power reactors with improved heat removal system – up to 60-75 thousand tons / year..
Flowsheet producing HDPE in the solution is carried out usually in hexane at 160-250 ° C and a pressure of 3,4-5,3 MPa in the presence of titanium catalyst or a magnesium-silica CrO3. The contact time with the catalyst of 10-15 min. Polyethylene was isolated from the solution by solvent removal in an evaporator in series, a separator and a vacuum chamber of the granulator. polyethylene pellets were steamed with water vapor at a temperature above the melting point of polyethylene to the water switched and low molecular weight polyethylene fraction neutralized the catalyst residues. Advantages of the solution before the polymerization in suspension polymerization that excludes extraction stages and the drying of the polymer, there is a possibility of utilization of heat of polymerization for the evaporation of solvent is facilitated regulation of molecular weight polyethylene.
Gas phase polymerization of ethylene is carried out at 90-100 ° C and a pressure of 2 MPa and a chromium compound on a silica gel as a catalyst. At the bottom of the reactor has a perforated grate for even distribution of the ethylene feed in order to create the fluidized bed in the upper – expanded area designed to reduce the gas velocity and collecting the resulting particles of polyethylene.
Product produced low density polyethylene colored and uncoloured, typically in granules of 2-5 mm diameter, at least – in the form of powder.
The use of different catalysts allows charging polyethylene varieties with improved performance characteristics.
Thus, polymerization in a solvent in the presence of oxides of Co, Mo, V at 130-170 ° C and a pressure of 3.5-4 MPa prepared medium density polyethylene (PESD), which chain branching less than 3 branches per 1000 carbon atoms, which increases its strength quality and thermal stability as compared to HDPE.
The metallocene catalysts make possible a controlled polymerization chain length, which allows to obtain a polyethylene with a given consumer characteristics.
If the polymerization takes place at low pressure in the presence of organometallic compounds, the obtained polyethylene with high molecular weight and strogolineynoy structure, which unlike conventional HDPE has higher strength characteristics, low friction coefficient and high wear resistance, crack resistance, chemical resistance to most aggressive environments.
LDPE obtained by chemical modification of linear low density polyethylene – LLDPE which is a lightweight flexible material crystallized with a Vicat softening point up to 118 ° C. More resistant to stress cracking, it has a higher impact strength and heat resistance than LDPE.
When filling LDPE starch can be obtained by a material of interest as a biodegradable material.
The main producers of high-density polyethylene for the Russian market:
Stavrolen – particularly Stavrolen RE4FE69, Stavrolen RE4EC04S, Stavrolen RE3IM61, Stavrolen RE0VM45, Stavrolen RE3OT49, Stavrolen RE4VM42, Stavrolen, RE4VM50V, Stavrolen RE4VM41, Stavrolen REES05, ​​Stavrolen RE4RR25V;
Kazanorgsintez – in particular HDPE 277-73, 276-73 HDPE, LDPE 293-285D, 273-83 HDPE, LDPE PE80B-275, HDPE PE80B-285D, HDPE 273-79;
Shurtan Gas Chemical Complex – in particular, B-Y456, B-Y460, I-0760, I-1561.
The main producers of high-density polyethylene for the Russian market:
Kazanorgsintez – in particular LDPE 15813-020, 15313-003 HDPE, LDPE 10803-020;
Tomskneftekhim – in particular LDPE 15803-020, 15313-003 LDPE;
Ufaorgsintez – in particular LDPE 15803-020.
The main producers of polyethylene cable brands for the Russian market:
Kazanorgsintez – in particular, PVD 153-02K, LDPE 153-10K, 271-274K;
Shurtan Gas Chemical Complex – in particular, WC-Y436.
Polyethylene pipe grades P-Y337 MDPE, P-Y342 HDPE, P-Y456 HDPE produces Shurtan Gas Chemical Complex. The same company produces polyethylene film F-Y346, F-0220S, F-0120S, F0120, F0220.

Application: Polyethylene – the most widely used polymer. It is a leader in the global release of polymeric materials – 31.5% of the total volume of produced polymers. products manufacturing technology of polyethylene is relatively simple. It can be exposed by all known methods of processing. Welded all major ways: hot gas, filler rod, friction, resistance welding.
To work with the polyethylene does not require the use of highly specialized equipment, such as for processing PVC, and modern industry produces hundreds of brands of additives and dyes to give the products of polyethylene wide variety of consumer qualities.
Using injection molding, polyethylene is produced a wide range of household goods, stationery, toys. When using extrusion obtained polyethylene pipes (there is a special brand – Pipe PE63, PE80, PE100), polyethylene cables (XLPE very promising), polyethylene sheet for packaging and construction, as well as a wide variety of plastic films for the needs of all industries. Extrusion blow molding and rotational molding of polyethylene create all sorts of containers, vessels, containers. Thermal vacuum molding – a variety of packaging materials. Various special types of polyethylene, such as cross-linked, expanded, chlorosulfonated, ultra-high molecular successfully used to create special materials. A separate segment of the modern market – recycled polyethylene. Many companies in Russia and in the world specializing in the purchase of plastic waste from further processing and the sale or use of recycled polyethylene. Typically, this technology is applicable purified extruding and subsequent crushing waste and produce secondary granulated material suitable for manufacturing products.
The most widely used for the production of polyethylene films for technical and household purposes. Advantages of all types of polyethylene for packaging purposes: low density, good chemical resistance, small water absorption, good transparency, easy processability, good weldability, impermeability to water vapor, high strength, flexibility, extensibility, and elasticity. The polyethylene film used for the production of bags for bread, vegetables, meat, poultry, garbage bags, packaging films for securing cargo. LDPE is used for the manufacture of composite films by coextrusion with other thermoplastic polymers, for application to paper, cardboard, cellophane, aluminum foil. In all of these films combined LDPE film layer imparts excellent weldability, and other layers – the strength and impermeability to odors. For certain properties realize the transformation of polyethylene vinyl acetate. These films are more transparent and better welded with good strength. Thanks to this the heating and adhesion with other materials, they are also suitable for use on board and other packaging materials. Domestic ethylene-vinyl acetate copolymer obtained by copolymerization of ethylene and vinyl acetate in weight under high pressure, known under the trademark Sevilen which is widely used in the manufacture of hoses twisted vozduhootsosov of various equipment.
Polyethylene is used for the production of:
films: agricultural, packaging, shrink, stretch;
tubes: gas, water, pressure, non-pressure;
tanks: tanks, cans, bottles;
building materials;
fibers;
household goods;
sanitary ware;
parts of vehicles and other equipment;
electrical cable insulation;
foam;
internal organs prostheses;
And this is not the limit of possibilities of using polyethylene. Especially because the market is constantly come out with new brands of this polymer with new consumer properties.
For example, ultra-high molecular weight polyethylene (UHMWPE) used for the manufacture of high-technology products, resistant to impact, abrasion and cracking: gears, bushings, couplings, rollers, rollers, sprockets, and insulating parts of equipment operating in high and ultra-high frequency range. In addition, the UHMWPE is widely used in the manufacture of porous products: filters, silencer, gasket, and in arthroplasty – to create joints, cranial and maxillofacial prostheses.