. It is established that the studied samples of polyethylene products contain different types of organic and macromolecular structures. The ratio of substances in the composition of polyethylene materials was identified using IR spectroscopy, density, melt flow rate (MFR). Objective: to study the composition and properties of a composite material based on polyethylene.
Анотація наукової статті по промисловим біотехнологій, автор наукової роботи - Khamrokulov Makhmud G'Afurdjanovich, Asqarov Ibrohimjon Raxmonovich
Текст наукової роботи на тему «39 GROUP OF COMMODITY NOMENCLATURE FOR FOREIGN ECONOMIC ACTIVITY OF THE REPUBLIC OF UZBEKISTAN: IDENTIFICATION AND THEIR CLASSIFICATION»
39 GROUP OF COMMODITY NOMENCLATURE FOR FOREIGN ECONOMIC ACTIVITY OF THE REPUBLIC OF UZBEKISTAN: IDENTIFICATION AND THEIR CLASSIFICATION
Abstract. It is established that the studied samples of polyethylene products contain different types of organic and macromolecular structures. The ratio of substances in the composition of polyethylene materials was identified using IR spectroscopy, density, melt flow rate (MFR).
Objective: to study the composition and properties of a composite material based on polyethylene.
Keywords: polyethylene, classification of goods, commodity nomenclature of foreign economic activity (CNFEA) of the Republic of Uzbekistan, identification features.
The aim of this work is to study the physic-me- Nomenclature in International Economic Relations chanical and physic-chemical indicators of polymeric materials, create a classification of goods based on a comprehensive analysis of code numbers for the commodity nomenclature of foreign economic activity ( CNFEA RUz) of polymeric materials, develop new code numbers for polymeric materials that can protect Uzbekistan's economic interests in international relations.
The widespread usage of polymeric materials in industry and in everyday life is due to the availability of raw materials, ease of processing into products, and the possibility of obtaining products with predetermined properties. Many products are purchased in the form of semi-finished products from abroad. When transporting across the border of the state, products and materials from polymers undergo customs examination of quality.
With the improvement of CNFEA there are certain shortcomings in the classification of goods. Therefore, the creation of the National Commodity
is considered the most urgent task.
Customs clearance and customs control of polymers in primary forms and products made of them is in most cases accompanied by the involvement of experts or qualified specialists in the relevant field of knowledge, since the control of the code of such goods in the HS of the Republic of Uzbekistan is difficult due to the specificity of classification criteria and the lack of a comprehensive information base. The application of the procedural mechanism of interaction with expert organizations lengthens the timeframes for decision-making; many issues arising in the process of customs control of polymers in primary forms and products from them can basically be resolved on the spot. In practice, in most cases, for the identification of many materials from which the goods are made, an examination is appointed, and the expert opinions obtained are used for insurance.
However, there are often problems determining an unambiguous classification code for a product,
therefore, customs authorities resort to the appointment of a customs identification examination [1, 129-130].
VII section of the CNFEA of the Republic of Uzbekistan "Plastics and products from them; caoutchouc, rubber and articles" is intended for the classification of goods from plastic and rubber, both raw materials and products of their processing. The basic principle of building the section is the chemical composition of the goods. This section includes two groups 39 and 40. The general criterion for classifying goods as part of a section is structure - these are polymers, the difference is based on the criterion for the presence of elastic properties.
The structural content of the section groups defines the identification of goods as:
The objects of classification of Section VII of the CNFEA are plastics, caoutchouc and rubber. These products are presented in the following forms:
- Semi-finished products;
For the classification of goods in this section, the priority classification principle is structure, since polymers are ordered units consisting of monomers.
Group 39 "Plastics and articles thereof" includes two subgroups depending on the degree of processing:
- I subgroup - these are primary forms;
- II subgroup - this is waste, scrap and scrap; semi-finished products; products.
For the purposes of classification, it should be noted which goods belong to the primary forms in group 39 - these are: liquids, pastes, powders, granules, irregularly shaped blocks, bulk forms which, upon receipt, are not processed. The goods of the second subgroup include: waste, scrap and scrap, pipes, tubes, hoses, plates, sheets, film, strips, tapes, porous plastics, products that are formed during processing or are formed during the disposal of polymer products. [2, 263]
The main features of the classification of plastics in primary forms are: the type of polymer, specific gravity, structure, physical properties, composition, shape and size of granules, state of aggregation, hy-
droxyl number, purpose and safety of their use. Polymers of ethylene, in primary forms:
3901 10 - Polyethylene having a specific gravity of less than 0,94 3901 20 - Polyethylene having a specific gravity of 0,94 or more 3901 30 - Ethylene-vinyl acetate copolymers 3901 90 - others
Polyethylene (high pressure polyethylene (HPPE), low-pressure polyethylene (LPPE), etc.) are materials that are made from one monomer, but can be of different densities depending on the features of the technology for their manufacture. This indicator strongly affects the properties of polyethylene: an increase in density leads to increased stiffness, hardness, strength of products and their chemical resistance. But at the same time, other indicators fall: impact resistance, the possibility of stretching at break, permeability to liquids and gases. So, HPP has significant differences from other similar polymers: • HPPE and LPPE. It is not for nothing that high-pressure polyethylene is also called low-density poly-
ethylene (LDP or LDPE). Compared to it, such solid polymers as LPPE low-pressure polyethylene are more susceptible to rupture under the influence of impact, more often break in frost and crack when the load is increased, although they are more resistant to radiation, alkalis and acids. HPPE pellets and articles made of them are much better at transmitting ultraviolet radiation, and also have a more beautiful glossy surface.
• LHPE and LLPPE. Another polymer - LLPPE (linear polyethylene), like HDPE, has a rigid structure, but in terms of its technical characteristics it is between HPPE and LPPE. It is more resistant to chemically aggressive environments than LDPE, and has greater resistance to puncture and cracking than LPPE.
Low density polyethylene (LDPE), namely polyethylene having a specific gravity at 20 ° C of less than 0.94 (calculated for the polymer without any additives), is mainly used in the form of a packaging film, especially for food products, as a paper coating, wood fiber plates, aluminum foil, etc., as an insulating material and for the manufacture of various household products, toys, etc. This heading also covers linear low-density polyethylene (LLDPE). High Density Polyethylene (HDPE) is a polyethylene having a specific gravity at 20 ° C of 0.94 or more (calculated for a polymer without any additives). It is used for the manufacture of various products by blow molding and injection mold-
Table 1.- Grades of polyethylene,
ing, the manufacture of woven bags, containers for gasoline and oil, pipes by extrusion, etc. Copolymers ofethylene and vinyl acetate are used for the manufacture oflids, container liners and stretch packaging .
We have studied the characteristics, physic-mechanical indicators and classifications of polyethylene grades of the joint venture LLC "Shurtan Gas-Chemical Complex". IR spectroscopic studies were carried out on a spectrometer (Perkin Elmer Spectrum Version 10.4.3).
The polyethylene products of the Shurtan gas chemical complex are diverse, and polyethylene grades are used for different purposes (table-1).
Shurtan gas-chemical complex 
№ Polyethylene grade Density, g / cm3 MFR, g / 10 min Recommended processing method and scope
F-0120 Linear low density polyethylene LLDPE FILM BRANDS For films and film
1. 0.9180-0.9220 0.70-1.50 Extrusion products of general purpose.
2. R-0333 U Medium Density Polyethylene 0.9310-0.9355 2.50-3.30 Rotational For large-sized products (tanks and boxes
Mdpe ROTARYBRANDS molding for agrochemical products, fuel).
3. 1-0760 High Density Polyethylene HDPE 0.9580-0.9620 5.5-8.5 Injection molding For the manufacture of containers - bas-
CASTING BRANDS kets, boxes, etc.
4. F-Y346 High Density Polyethylene HDPE FILM BRANDS 0.9400-0.9480 0.19-0.31 Extrusion For films and film products (bags).
5. P-Y342 High Density Polyethylene HDPE PIPE BRANDS 0.9400-0.9440 0.24-0.36 Extrusion For the manufacture of tubular products.
6. B-Y460 High Density Polyethylene HDPE CABLE BRANDS 0.9580-0.9620 0.33-0.46 Blowing For molding bottles, for packaging and storage of food liquids (water, juices, drinks).
Polyethylene grades have different physicome- production. Currently, there are three methods for chanical and physicochemical properties. The prop- the production of polyethylene: high, low and medi-erties of polyethylene depend on the method of its um density, which differ in structure and properties.
The test samples were taken in the form of gran- structures of six grades of polyethylene were stud-ules. Using infrared spectroscopic analysis, the ied (Fig. 1).
High Density Polyethylene
Linear low density polyethylene
High density polyethylene
High density polyethylene
-E - V.
4000 3500 3000 2500 2000 1500 1000 500
Wave number (cm-1)
High density polyethylene
4DOO 3500 3000 2500 2000 1SOO 1000 500
Wave number (cm-1)
Medium density polyethylene
Figure 1. IR spectra of polyethylene
And also, various organic inclusions of polyethyl- From the analysis of the spectral results, it was ene were determined by determining the absorption shown that in all the studied samples there are alde-bands in the IR spectrum. hyde and chlorine derivatives ofpolyethylene (table-2).
Table 2.- Identification of the chemical composition of polymers by IR spectroscopy [5, 7-9]
№ Sample Name Substance identified during analysis Communication (frequency, cm-1)
1. I-0760 - Aldehydes - Hydrocarbons v CH 2800- 8a CH3 1450- va CC13 700-
(HDPE) - a) alkanes RCH3 - Chloro derivatives 2900 1475 830
- Amines: b) primary
- aromatic: ArNH2
2. F-0120 (LLDPE) - Hydrocarbons - a) alkanes RCH3 vs 2 NH 3325- vCH 2800- ^ NH2 1590- 8a CH3 1450- VCO 1000- va CC13 700-
- Primary alcohols 3420 2900 1650 1475 1075 830
- Chloro derivatives
- Aldehydes 8a CH3 14501475 Va
3. F-Y346 (HDPE) - Hydrocarbons - a) alkanes RCH3 - Chloro derivatives CH 28002900 CC13 700830
- Primary alcohols
4. P-Y342 (HDPE) - Aldehydes - Amines: a) primary aliphatic: RCH2NH2 - Hydrocarbons - a) alkanes RCH3 - Chloro derivatives v OH 32003400 v CH 28002900 Snh2 15901650 SaCH3 14501475 va CC13 700830
- Primary alcohols
5. B-Y460 (HDPE) - Aldehydes - Aromatic - Hydrocarbons - a) alkanes RCH3 - Phenols ArOH - Chloro derivatives v OH ~ 3640 v CH 28002900 v CH 16602000 SaCH3 14501475 SOH 13301390 va CC13 700830
- Primary alcohols
6. R-0333 (MDPE) RCH2OH - Aldehydes - ArNO2 - Chloro derivatives nOH ~ 3640 nCH 28002900 ns 13301370 v CO 10001075 va CC13 700830
The rates of import / export customs duties, respectively, and the amount of customs duties paid, application of non-tariff measures, prohibitions and restrictions to goods and vehicles depend on the correctness of the classification code of the CNFEA of the Republic of Uzbekistan. In particular, the unam-biguity of the classification of goods is also of great importance for increasing the objectivity of customs statistics of foreign trade used in the development of customs policy of the state and the adoption of specific measures for its implementation in the process of customs control of goods and vehicles. [6, 46-47]
Depending on the chemical nature of the monomer and the presence of intermolecular interactions between the macromolecules, the formation ofpolymers ofa linear, branched and network structure is possible.
Most linear and branched polymers can crystallize. These include polyolefins, polytetrafluoroethyl-ene, polyformaldehyde, isotactic polystyrene, rubber and others. During crystallization of polymers, strength, density increases and elongation and their solubility in solvents decrease. So, in polypropylene, strength increases from 14 MPa, in the amorphous state, to 37 MPa in crystalline. At the same time, a decrease in elongation ability from 500% to 240% is observed. Therefore, to select the optimal temperature-time regimes for processing such polymers, their storage and operation, it is necessary to have an idea of their crystallization and properties of the formed crystallites [7, 12].
The geometric shape of macromolecules significantly affects the properties of polymers :
• linear and branched polymers are thermoplastic; when heated, linear polymers melt, can dissolve in appropriate solvents. Branched polymers dissolve poorly or do not dissolve at all and melt more difficult than linear ones;
• linear polymers have the highest density, their macromolecules are capable of orientation along the axis of a directed mechanical field (this property is used, for example, in the formation of fibers and films);
• crosslinked polymers do not melt and do not dissolve, but only swell in solvents; the determination of molecular weight for such polymers loses its meaning (there are no separate macromolecules, all chains are sewn into a single network). Mesh structures can be obtained from thermosetting polymers (table-3).
The results of the work make it possible to classify polyethylene in primary forms by molecular structure. In conclusion, it should be noted that the study of the classification of ethylene polymers by their physicochemical composition can clarify some controversial issues of the CNFEA of the Republic of Uzbekistan. And also it can be noted that, the studied brands ofpolyethylene are classified at position 3901 according to the CNFEA RUz [2, 265].
The development of new product codes makes it possible to protect the economic interests and security of the economy of Uzbekistan in international relations.
Polyethylene Structure Mol. mass Density, g / m3 Melting point, ^ Elastic modulus, MPa V solubility, MPa
1 2 3 4 5 6 7
Low density (high pressure) Branched 50-800 thousand 0.913-0.914 102-105 100-200 7-17
High density (low pressure) Branched 3.0 x 106 0.919-0.973 125-137 400-1250 15-45
Linear Without branched 200-500 thousand 0.915-0.980 125-140 400-1600 15-60
Table 3.- The main technical characteristics of various polyethylenes
1 2 3 4 5 6 7
Cross-linked Cross-linked structure 5.0 x 106 and higher 0.920-0.970 145-160 600-1800 40-80
Super high molecular Linear 10.0 x 106 and higher 0.940-0.980 160-190 700-2000 80-120
The listed varieties of polyethylene by chemical composition include polyethylene consisting of carbon and hydrogen. However, they differ significantly in molecular weight, structure, density, melting point, modulus of elasticity, price and other properties associated with the conditions of their production, their areas of application and their cost.
Given this, we believe that it is necessary and recommended to divide them and determine the code numbers for the indicated varieties of polyethylene according to the HS of Uzbekistan.
To identify varieties of polyethylene during the examination, it is sufficient to conduct their tests in accordance with the indicators given in tables-3.
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