High-pressure Polyethylene Research Articles

ВЛИЯНИЕ ШУНГИТА НА ТВЕРДОСТЬ КОМПОЗИЦИОННОГО МАТЕРИАЛА НА ОСНОВЕ ПОЛИЭТИЛЕНА ВЫСОКОГО ДАВЛЕНИЯ

Experimental samples of composite material based on high-pressure polyethylene 16803-070 filled with dispersed shungite, a natural environmentally friendly filler, have been obtained. High-pressure polyethylene and shungite were combined in a single-screw laboratory extruder. The effect of shungite on the mechanical properties of the presented composite material has been established. An analysis of the obtained experimental data has been conducted, which has shown that dispersion of shungite in the binder volume in an amount from 20 to 35 mass. % allows increasing the hardness of high-pressure polyethylene. The studied samples have been subjected to secondary processing. In the process of analyzing its results, the possibility of recycling the obtained material with a deterioration in its mechanical characteristics by no more than 4 % has been revealed

Nickel-Containing Nanocomposites Based on Isotactic Polypropylene and High-Pressure Polyethylene

Nickel-Containing Nanocomposites Based on Isotactic Polypropylene and High-Pressure Polyethylene

Comparative characteristics of thermal stability of polyethylene in the presence of complex fillers based on natural raw materials

A comparative analysis of the effect of new complex fillers of natural origin on the process of thermal aging of high-pressure polyethylene is carried out. During the research, it was found that the studied fillers have a stabilizing effect, inhibiting the processes of thermal oxidation of high-pressure polyethylene. The stabilizing effect of fillers is due to the presence in their composition of metal oxides capable of chemical interaction with oxygen-containing groups in oxidized polyethylene. It has been established that the carbon-mineral filler has a higher thermostabilizing effect than the carbon-silicon filler from carbonized rice husk.

Influence of Discharges and UV Irradiation on the Electrical Properties of High Pressure Polyethylene and Compositions on Its Base

ABSTRACT The composition and concentration of a low-molecular organic additive, leading to a significant improvement in the electrical properties of low-density polyethylene of high pressure grade 10,803-020, were experimentally determined. Phthalic anhydride and phthalic acid were used as modifying organic additives. The content of additives in the polyethylene of high pressure composition varied in the range of 0.01–0.1 wt%. It has been shown that the content of 0.05 wt% phthalic anhydride and phthalic acid in the composition polyethylene of high pressure (PEHP + 0.05 wt% PhAn + 0.05 wt% PhAc) is the optimal composition, since the electrical strength of the film has increased significantly. The dependences of the dielectric loss tangent and specific volumetric electrical resistance on temperature, as well as the kinetics of physicochemical changes in them under the influence of electrical discharges in air and UV irradiation, have been studied. It was established that the dielectric characteristics of the polymer composition PEHP + 0.05 wt% PhAn (storage life 40 years) changed slightly.

The effect of nickel oxide nanoparticles on the structure and properties of nanocomposites based on high-pressure polyethylene containing multiwalled carbon nanotubes

The effect of nickel oxide nanoparticles on the structure and properties of nanocomposites based on high-pressure polyethylene containing multiwalled carbon nanotubes

Никельсодержащие нанокомпозиты на основе изотактического полипропилена и полиэтилена высокого давления

The effect of nanofiller (NF) additives containing nickel oxide nanoparticles stabilized by a polymer matrix of high pressure polyethylene (PE) obtained by the mechanochemical method on the structure and properties of metal-containing nanocomposites based on isotactic polypropylene (PP) and high pressure polyethylene(PE) using differential thermal (DTA) and X-ray phase (XRF) and SEM analyzes. The improvement of strength, deformation and rheological parameters, as well as thermal-oxidative stability of the obtained nanocomposites was revealed, which, apparently, is associated with the synergistic effect of interfacial interaction of nickel-containing nanoparticles in the PE matrix with the components of the PP/PE polymer composition. It is shown that nanocomposites based on PP/PE/NF can be processed both by pressing method and by injection molding and extrusion methods, which expands the scope of its application.

Modification and study decommissioned high pressure polyethylene

Modification and study decommissioned high pressure polyethylene

The effect of integrated nickel oxide nanoparticles and carbon nanotubes on the mechanical and thermal properties of high-pressure polyethylene composites

The effect of integrated nickel oxide nanoparticles and carbon nanotubes on the mechanical and thermal properties of high-pressure polyethylene composites

ИСПОЛЬЗОВАНИЕ МОДИФИЦИРОВАННОГО УГЛИСТОГО СЛАНЦА МЕСТОРОЖДЕНИЯ БАЛА-САУСКАНДЫК В КАЧЕСТВЕ ДИСПЕРСНОГО НАПОЛНИТЕЛЯ ДЛЯ ПОЛИЭТИЛЕНА

Currently, researchers are paying great attention to the use of waste from the mining and metallurgical industries as components of polymer composite materials. This makes it possible not only to use them as a valuable secondary resource, to create new composites with certain consumer qualities, to expand the range of polymer products, but also to solve a number of environmental problems. The influence of a new modified filler of natural origin obtained from waste from autoclave leaching of vanadium ore at the Bala-Sauskandyk polymetallic mine on the properties of high-pressure polyethylene has been studied. The carbon-containing filler (CF) has a complex chemical composition. It contains 43.0-45.0% carbon, 48.0 - 51.0% silicon dioxide and a number of oxides, including metal oxides. Since the synergistic effect of the combined use of carbon black and silicon dioxide in rubbers is known from the literature to increase its strength, it was interesting to explore the possibility of using a new modified natural filler in polyethylene compositions. The effect of the new filler on the deformation and strength characteristics of polyethylene compared with talc is compared. It has been established that polyethylene filled with CF has better consumer properties than filled with talc. Thus, the use of CF filler obtained from waste after autoclave leaching of vanadium ore as a filler for polyolefins is promising for reducing the cost of polymer composite materials, expanding their range and reducing the environmental burden. This will expand the approach to the use of waste-free technologies in polymer materials science.

Optical Spectra of Composite Materials Based on Molybdenum-Containing Nanoparticles and High-Pressure Polyethylene

Optical Spectra of Composite Materials Based on Molybdenum-Containing Nanoparticles and High-Pressure Polyethylene

Optical Spectra of Composite Materials Based on Molybdenum- Containing Nanoparticles and High-Pressure Polyethylene

Molybdenum-containing composite nanomaterials are synthesized by the thermal decompositionof molybdenum hexacarbonyl in a solution-melt of polyethylene in mineral oil. The concentration of a metalcontainingfiller in the composite materials varied from 1 to 20 wt %. A technique for preparing film samplesfor spectroscopic studies is developed, and the samples obtained are studied by UVI, IR, and Raman spectroscopy.It is found that additional absorption bands appear in the IR range, whose intensity depends on theconcentration of molybdenum-containing nanoparticles in the composite materials. The spectral characteristicsof Raman scattering show that all samples are characterized by the stretching of the C–C bond. In thevisible light region, the spectrum of nanocomposites has a flat edge of its own absorption located in the regionof wave numbers (18–31) × 103 cm–1.

Influence of the phthalimide on the process of electrical aging of the high-pressure polyethylene

Relevance. The use of polyolefins without additional processing methods, namely, the increase in their electrophysical characteristics, is an actual modern requirement. For this, it is necessary to use the mechanism of ionization ageing where the role of the modifying additive must be elucidated by the method of infrared spectroscopy in high-pressure polyethylene. Purpose. The research aims to study the effect of low molecular weight organic additives of phthalimide on molecular structural changes in polymers that occur under external action. Methodology. The impact of electrical discharges on polymer dielectrics was carried out in a test cell of an asymmetric type. Tested polymer film before and after pre-stretching was tightly stretched onto this plate following the research procedure. To create an air gap of constant thickness between the top electrode and the polymer film, 1.5 mm thick glass spacers were placed along the edges. Results. The electrical strength (lifetime) of high-pressure polyethene (LDPE) and its optimal modification before and after electrical ageing was investigated. Following experimental data, at the content of 0.05 wt. % LDPE its electrical strength reaches a maximum value compared to both the original LDPE and LDPE at other additive contents. The introduction of 0.05 wt.% phthalimide into high-pressure polyethene contributes to a noticeable decrease in the intensity of the formation of C=0 groups, which is the measure of the oxidative degradation of polymer chains. Conclusions. The optimal composition of the phthalimide was determined and their electrophysical properties were studied. It was found that composites with additions of 0.05 wt.% phthalimide significantly improve the electrophysical properties of LDPE.

Obtaining and studying the properties of composites based on high pressure polyethylene with nickel-containing nanofillers

The effect of nickel nanoparticles stabilized by a polyethylene matrix on the physical-mechanical and thermal properties of nanocomposites based on high-pressure polyethylene was studied by X-ray phase (XRD) and differential thermal (DTA) analyzes.An improvement in the strength and deformation parameters, as well as the thermal-oxidative stability of the obtained nanocomposites was revealed, which can be attributed to the effects of structural modification of the polymer matrix.Small amounts of nanofiller introduced into the polymer play the role of structure-forming agents - artificial nuclei of crystallization, which contributes to the formation of a small-spherolite structure in the polymer, characterized by improved physical, mechanical and thermal properties of the obtained nanocomposite.fi

Nanocomposites Based on Polyethylene and Nickel Ferrite: Preparation, Characterization, and Properties.

Composite materials based on NiFe2O4 nanoparticles and polyethylene matrix have been synthesized by thermal decomposition to expand the application area of high-pressure polyethylene by filling it with nanoscale particles. The synthesized compositions were obtained in the form of a dark gray powder and compressed for further study According to TEM, the average particle size in composites was 2, 3, and 4 nm in samples with a filling of 10%, 20% and 30%. The concentration dependences of the specific electrical resistivity ρV, dielectric permittivity ε, saturation magnetization MS and the parameters of reflection and attenuation of microwave power of the obtained composites were investigated. The threshold for percolation in such materials is found to be within a concentration range of 20…30%. The electronic and atomic structure of composites was studied by methods of Mössbauer spectroscopy, X-ray diffraction and X-ray absorption spectroscopy. The closest atomic environment of nickel and iron in nanoparticles is close to that of crystalline NiFe2O4. The dependence of the nanoparticles size as well as the dependence of the number of tetrahedral or octahedral iron positions in nickel ferrite nanoparticles to their content in polyethylene matrix is established. It is shown that composite materials based on NiFe2O4 nanoparticles and polyethylene matrix can be used as components of electromagnetic compatibility systems.

OBTAINING AND STUDYING THE PROPERTIES OF NANOCOMPOSITES BASED ON A MIXTURE OF HIGH AND LOW PRESSURE POLYETHYLENE WITH METAL-CONTAINING NANOFILLERS

The effect of additives of nanofillers (NF) containing nanoparticles of copper (I) oxides stabilized by a polymer matrix of high-pressure polyethylene (PE) obtained by the mechano-chemical method on the structure and properties of metal-containing nanocomposites based on a mixture of high- and low-pressure polyethylene has been studied by differential thermal (DTA), X-ray phase (XRD) and scanning electron microscopy (SEM) analyses. It is shown that the introduction into the composition of 0.3 – 0.5 wt.% NF leads to an increase in the strength index from16.69 to 19.77 MPa and the amount of deformation at break of the composite by 1.7 times, which is apparently due to the synergistic effect re-lated to the interfacial interaction of copper-containing nanoparticles in the LDPE matrix with the components of LDPE/HDPE composition , the mutual influence of which contributes to an increase in both the amount of deformation and the strength index. The study of the thermal properties of the samples has showed that the introduction of NF containing copper(I) oxide NPs into the composition of mixed polyethylene contributes to a significant increase in the decay temperature of the samples, and the activation energy of the decay of the thermo-oxidative destruction of the resulting nanocomposite increases from 232 to 255 kJ /mol. The results obtained indicate that small amounts of nanofillers (0.3-0.5wt. %), introduced into the polymer, obviously play the role of structurizers - artificial nuclei of crystallization, which contributes to the appearance of a fine-spherulite structure in the polymer, characterized by improved physico-mechanical and thermal properties of the resulting nanocomposite

Modification of High-Pressure Polyethylene and Ethylene–Vinyl Acetate Copolymer with Sepiolite Chain-Layered Silicate

Modification of High-Pressure Polyethylene and Ethylene–Vinyl Acetate Copolymer with Sepiolite Chain-Layered Silicate

Blending of the Thermodynamically Incompatible Polyvinyl Chloride and High-Pressure Polyethylene Polymers Using a Supercritical Fluid Anti-Solvent Method (SEDS) Dispersion Process.

The experimental solubility data of polyvinyl chloride (PVC) and high-pressure polyethylene (HPPE) in organic solvents (toluene, dichloromethane, and chloroform) at temperatures ranging from 308.15 to 373.15 K at atmospheric pressure are reported in the present paper. The solubility of the polymers (PVC and HPPE) in organic solvents (toluene, dichloromethane, and chloroform) was studied at temperatures between 298 and 373 K. The supercritical SEDS dispersion of PVC and HPPE polymer blends at pressures between 8.0 and 25 MPa and at temperatures from 313 to 333 K are reported in the present work. The kinetics of crystallization and phase transformation in polymer blends obtained by blending in a melt, and using the supercritical SEDS method, have been studied. The effect of the HPPE/PVC ratio on the thermal and mechanical characteristics of the polymer blends has been studied. For all studied polymer blends and pure polymers obtained using the SEDS method, the heat of fusion ΔfusH exceeds the values obtained by blending in the melt by 1.5 to 5) times. The heat of fusion of the obtained polymer blends is higher than the additive value; therefore, the degree of crystallinity is higher, and this effect persists after heat treatment. The relative elongation decreases for all polymer blends, but their tensile strength increases significantly.

Factors Influence on Electrophysical Parameters of the Composite Varistors

Purpose. Evaluation influence structural state polymer phase on the response voltage and coefficient nonlinearity of a multilayer varistor based on zinc oxide. Methodology. Zinc oxide consisted of 97% zinc oxide and 3% total oxides of Bi2O3, Co3O4, MnO2, B2O3, SbO3, ZrO2, Al2O3. At a temperature of 1573°K, the synthesis of semiconductor ceramics based on Zinc oxide was carried out. For composite of thermoplastic polymers and Zinc oxide, non-polar and polar polymers, high pressure polyethylene and polyvinylidene fluoride were used. The composites were obtained by hot pressing at the melting temperature of the polymer phase and a pressure of 15 MPa. After that, using silver paste, measuring electrodes 10 mm in diameter were applied to the surface of the synthesized samples, and then current–voltage characteristics were measured. Modification of composites under action of gas-discharge plasma was carried out in a special cell that creates a dielectric-gas-composite system. The structure of the composites was studied by X-ray diffraction analysis and IR spectroscopy. Findings. The obtained experimental results show that the size of the particles of the inorganic phase significantly affects the current-voltage characteristics of the composite varistor: at a given thickness of the composite varistor, the operation voltage decreases markedly, and the nonlinearity coefficient increases. Numerous experimental results obtained by us show that the impact of electric discharge plasma on the polymer Zinc oxide-composite leads to a significant change in the permittivity and the concentration of local levels at the interface of the composite. The results research showed that effect electrical plasma on the opening voltage depends on the polarity of polymer matrices. Moreover, plasma processing itself significantly changes the structure of the polymer phase at composite. Originality. The magnitude of the potential barrier at phase boundary is mainly determined by the volume fraction and size of the main structural element of ZnO ceramics. Changing the structural state of the polymer matrix allows the adjust response voltage and coefficient nonlinearity of volt-ampere characteristic of the multilayer varistor. Practical value. The discovered development of electron-ion processes at polymer phase of the varistor indicates the need to take into account change in its service characteristics from the duration and intensity of use. The result obtained has a certain practical significance, since it indicates not only the reason for the change in properties, but also the need to develop measures to increase the service life of the varistor.

Dependence of current conductivity of polyethylene-graphite compositions on the method of their manufacture

The paper presents the results of the study of the dependence of the properties of polymer composites of the linear high-pressure polyethylene (LHPPET) system – graphite fillers of various types: natural GAK-2, thermally expanded (TEG) and with ultrasonic treatment. The test samples contained a filler in a wide concentration range (5–35 wt. %). Samples were manufactured using rolling, pressing and powder technology methods. Electrical resistance was measured by the four-probe potentiometric method at constant current. It is shown that the electrical resistance decreases sharply in a narrow concentration interval of 5–15 wt. % from 6.77·1010 to 4.9·102 Ω·m (for compositions obtained by rolling), from 2.96·1010 to 1.2 Ω·m (for pressed samples), from 2.87·109 to 0.14 Ω·m (for compositions obtained by powder technology). For samples of the LHPPET – GAK-2 system, a rapid decrease in electrical resistance is observed at filler concentrations of 5–30 wt. % from 1.36·1012 Ω·m to 2.79·102 Ω·m. Using thermally expanded graphite with and without ultrasonic treatment (and to a lesser extent GAK-2) it is possible to obtain polymer composite materials (PCM) with volume resistivity ranging from 6.77 to 1.9·10-3 Ω·m. It has been experimentally confirmed that electrical conductivity largely depends on the PCM manufacturing technology. The established dependences of the current conductivity of composites, depending on the manufacturing method, are associated with the corresponding structural differences. These structural differences are manifested in an increase in the number and area of contacts of filler particles – graphite and in a change in the thickness of the layers of the polymer matrix. Dry powder technology is the most effective method of obtaining LHPPET – graphite compositions. The optimal composition of the composition is 25 wt. % TEG and 75 wt. % LHPPET. Directions of practical use of the obtained results can be effectively used in industry and housing and communal economy.

Structural Optimization of High-Pressure Polyethylene Cyclone Separator Based on Energy Efficiency Parameters

The high-pressure polyethylene process uses cyclone separators to separate ethylene gas, polyethylene, and its oligomers. The oligomers larger than 10 microns that cannot be separated must be filtered through a filter to prevent them from entering the compressor and affecting its normal operation. When the separation efficiency of the cyclone separator is low, the filter must be cleaned more frequently, which will reduce production efficiency. Research shows that improving the separation efficiency of the separator is beneficial for the separation of small-particle oligomers and reduces the frequency of filter cleaning. For this reason, Computational Fluid Dynamics simulations were performed for 27 sets of cyclone separators to determine the effects of eight structural factors (cylinder diameter, cylinder height, cone diameter, cone height, guide vane height, guide vane angle, exhaust pipe extension length, and umbrella structure height) on separation efficiency and pressure drop. The equations for separation efficiency and pressure drop using these eight factors and the equations based on energy-efficiency parameters were determined. The optimization analysis showed that separation efficiency can be improved by 98.7% under the premise that the pressure drop is only increased by 8.2%. By applying the improved structure to the high-pressure polyethylene process, separation efficiency is increased by 17.7%, which could effectively reduce the frequency of filter cleaning for this process, and thereby greatly improve production efficiency.