scholarly journals Study of Electric Conductivity of Low-Density Polyethylene with Copper Nanoparticles

2021 ◽  
Vol 15 ◽  
pp. 1429-1435
Author(s):  
O. S. Tarasenko ◽  
Kyaw Ye Ko
Keyword(s):  
Electrical Conductivity ◽  
Polymer Nanocomposites ◽  
Temperature Shift ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Flow State ◽  
Low Frequencies ◽  
The Matrix ◽  
High Concentrations ◽  
Increasing Temperature

In this work, Cu/LLDPE composites are obtained and it is shown that the method of combining the formation of the composite and the nanodispersed phase in the viscous-flow state of the polymer makes it possible to achieve a uniform distribution of nanoparticles in the matrix. The dielectric properties of the composites have been investigated. A change in the mechanism of electrical conductivity was revealed when the concentration of the nanodispersed phase was varied. At low frequencies, nanocomposites of this type exhibit through conductivity. It was found that no pronounced relaxation peaks are observed in the studied polymer nanocomposites. However, at high concentrations of the added additive > 20%, two weakly pronounced peaks appear in the region of low and high temperatures, which, with increasing temperature, shift towards higher frequencies

scholarly journals Evaluación de la migración de bromuro de cetilpiridinio desde nanocompósitos activos hacia un simulante graso de alimentos/Cetylpyridinium bromide migration assessment from active nanocomposites to a fatty food simulant

2020 ◽  
Author(s):  
C. Muñoz-Shugulí ◽  
F.J. Rodríguez ◽  
E. Muñoz ◽  
M.J. Galotto
Keyword(s):  
Electrical Conductivity ◽  
Food Packaging ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Polymeric Nanocomposites ◽  
Cetylpyridinium Bromide ◽  
Active Food Packaging ◽  
Food Simulant ◽  
Fatty Food ◽  
The Matrix

En los últimos años, el desarrollo de nanocompósitos poliméricos se plantea como una interesante alternativa para el diseño de nuevos materiales para el envasado activo de alimentos. A pesar de esto, existe constante preocupación relacionada a la migración de los componentes activos incorporados en el material ya que, un material de envasado destinado a entrar en contacto con un alimento debe presentar valores de migración bajo los límites establecidos en regulaciones internacionales. En este sentido, el objetivo del presente trabajo fue evaluar la migración del surfactante bromuro de cetilpiridinio (CPB) desde nanocompósitos activos de polietileno de baja densidad y montmorillonita modificada con CPB, hacia un simulante graso de alimentos (etanol 95 %). El seguimiento de la migración del componente se realizó a través de la medición de la conductividad eléctrica del simulante en contacto con los nanocompósitos. Se determinó que la presencia del 3,0 % de organoarcilla permite una mayor migración del CPB debido a la presencia del surfactante libre en la matriz y al hinchamiento de la organoarcilla superficial por hidratación. Además, se observó que la migración es prolongada en el tiempo y está por debajo de los límites permitidos por la legislación estadounidense, lo que permitiría la generación de materiales novedosos que podrían ser empleados en el diseño de envases activos de alimentos. In the last years, the development of polymeric nanocomposites is presented as an interesting alternative for the design of new materials for active food packaging. Despite this, there are concerns regarding the migration of the components incorporated in the material since a packaging material intended to come into contact with food must have migration values under the limits established in international regulations. In this sense, the aim in this work was to evaluate the migration of the surfactant cetylpyridinium bromide (CPB) from active nanocomposites of low density polyethylene and motmorillonite modified with CPB to a fatty food simulant (ethanol 95 %). The migration of the component was followed by fat simulant electrical conductivity measurements during the contact with the nanocomposites. It was determined that materials with 3,0 % of organoclay allowed a higher migration of CPB due to the presence of free surfactant in the matrix and swelling of the superficial organoclay. In addition, it was observed that the migration is prolonged in time and it is below the limits allowed by US legislation, which would enable the generation of novel materials that could be used in the design of active food packaging. Palabras clave: surfactante, conductividad eléctrica, polietileno de baja densidad, organoarcilla, envase activo de alimentos. Keywords: surfactant, electrical conductivity, low density polyethylene, organoclay, food active packaging.

scholarly journals Thermal and Mechanical Behavior of Elastomers Incorporated with Thermoregulating Microcapsules

2021 ◽  
Vol 11 (12) ◽  
pp. 5370
Author(s):  
Ana M. Borreguero ◽  
Irene Izarra ◽  
Ignacio Garrido ◽  
Patrycja J. Trzebiatowska ◽  
Janusz Datta ◽  
...  
Keyword(s):  
Latent Heat ◽  
Continuous Improvement ◽  
Low Density Polyethylene ◽  
Molar Ratio ◽  
Low Density ◽  
Minimum Particle Size ◽  
Synergy Effects ◽  
Elastomeric Materials ◽  
The Matrix ◽  
Spherical Microparticles

Polyurethane (PU) is one of the principal polymers in the global plastic market thanks to its versatility and continuous improvement. In this work, PU elastomeric materials having thermoregulating properties through the incorporation of microcapsules (mSD-(LDPE·EVA-RT27)) from low-density polyethylene and vinyl acetate containing paraffin®RT27 as PCM were produced. Elastomers were synthesized while varying the molar ratio [NCO]/[OH] between 1.05 and 1.1 and the microcapsule (MC) content from 0.0 to 20.0 wt.%. The successful synthesis of the PUs was confirmed by IR analyses. All the synthesized elastomers presented a structure formed by a net of spherical microparticles and with a minimum particle size for those with 10 wt.% MC. The density and tensile strength decreased with the MC content, probably due to worse distribution into the matrix. Elastomer E-1.05 exhibited better structural and stability properties for MC contents up to 15 wt.%, whereas E-1.1, containing 20 wt.% MC, revealed mechanical and thermal synergy effects, demonstrating good structural stability and the largest latent heat. Hence, elastomers having a large latent heat (8.7 J/g) can be produced by using a molar ratio [NCO]/[OH] of 1.1 and containing 20 wt.% mSD-(LDPE·EVA-RT27).

The synthesis of organically modified layered double hydroxide and its effect on the structure and physical properties of low-density polyethylene/ethylene–vinyl acetate blends

2019 ◽  
Vol 27 (5) ◽  
pp. 287-298
Author(s):  
Xincheng Guo ◽  
Mengqi Tang ◽  
Na Wang ◽  
Lingtong Li ◽  
Yifan Wu ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Layered Double Hydroxide ◽  
Organic Anion ◽  
Ethylene Vinyl Acetate ◽  
Degree Of Crystallinity ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Organically Modified ◽  
The Matrix ◽  
Double Hydroxide

Organically modified layered double hydroxide (OM-LDH) was synthesized via anion exchange reaction and potassium monolauryl phosphate (MAPK) was used as an intercalator. The OM-LDH nanofillers were embedded into low-density polyethylene/ethylene–vinyl acetate (LDPE/EVA) via melt blending process which provided LDPE/EVA/OM-LDH nanocomposites. The structure and properties of the fabricated samples were characterized through Fourier transform infrared spectroscopy, X-ray diffraction techniques, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and tensile testing. The results showed that the organic anion was intercalated into the interlayer region of LDH and enlarged the interlayer distance. The TGA results of the nanocomposites showed significantly improved thermal stability at a higher temperature when containing 6 wt% OM-LDH due to the good dispersion of OM-LDH in the matrix. The DSC data indicated that the degree of crystallinity was increased obviously due to the incorporation of OM-LDH in the matrix. The formation of organic side chains on the OM-LDH surface also contributed to an improvement in the interfacial adhesion, resulting in enhanced tensile strength and elongation at break compared with LDH.

On the durability of low-density polyethylene nanocomposites

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Jitendra K. Pandey ◽  
Raj Pal Singh
Keyword(s):  
Ir Spectroscopy ◽  
Morphological Changes ◽  
Diffusion Path ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Neat Polymer ◽  
The Matrix ◽  
Ft Ir ◽  
The Stability ◽  
Artificial Uv

Abstract Low-density polyethylene (PE) containing nano-particulate clay was prepared after functionalization with maleic anhydride (MA) by reactive grafting in the presence of peroxide followed by blending of maleated PE with neat polymer in different concentrations. Four classes of composites were obtained: (i) exfoliated, (ii) intercalated, (iii) microcomposites, and (iv) intermediate of intercalated and microcomposites, as evidenced by wide-angle X-ray diffraction. All samples were kept for artificial UV irradiation (λ ≥ 290 nm) and for composting to study their photo- and bio-durability. Fourier-transform IR spectroscopy (FT-IR) and scanning electron microscopy were used to monitor the functional group and morphological changes, respectively, whereas biodurability was evaluated by measuring the weight loss. MA functionalization and nature of composites have detrimental effects on the overall durability of composites. Nanocomposites showed higher resistance than microcomposites during initial weathering and composting with a long induction period. The stability of nanocomposites decreases with time and overall durability was worse than of pristine polymer in both environments. It was concluded that the initial protection is due to the filler-generated long diffusion path, which decreases the oxygen diffusion through the matrix. The bio-durability of composites decreased with oxo-degradation. Biodegradation of PE nanocomposites during composting follows the mechanism described by Albertsson et al. as evidenced by FT-IR spectroscopy.

scholarly journals Pro-Degradant Activity of Naturally Occurring Compounds on Polyethylene in Accelerate Weathering Conditions

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 195 ◽  
Author(s):  
Nadka Tzankova Dintcheva ◽  
Delia Gennaro ◽  
Rosalia Teresi ◽  
Marilena Baiamonte
Keyword(s):  
Thin Films ◽  
Thermal Analysis ◽  
Vitamin E ◽  
Light Exposure ◽  
Low Density Polyethylene ◽  
Accelerated Weathering ◽  
Low Density ◽  
Naturally Occurring ◽  
Accelerate Weathering ◽  
High Concentrations

In this work, naturally occurring compounds, such as Vitamin E (VE) and Ferulic Acid (FA), at high concentrations, have been considered as pro-degradant agents for Low Density Polyethylene (PE). However, all obtained results using the naturally occurring molecules as pro-oxidant agents for PE have been compared with the results achieved using a classical pro-oxidant agent, such as calcium stearate (Ca stearate) and with neat PE. The preliminary characterization, through rheological, mechanical and thermal analysis, of the PE-based systems highlights that the used naturally occurring molecules are able to exert a slight plasticizing action on PE and subsequently the PE rigidity and crystallinity slightly decrease, while the ductility increases. To assess the pro-degradant activity of the considered naturally occurring compounds, thin films of neat PE and PE-based systems containing 2 and 3 wt.% Ca stearate, VE and FA have been produced and subjected to accelerated weathering upon UVB light exposure. All obtained results point out that the VE and FA, at these high concentrations, exert a clear pro-oxidant activity in PE and this pro-oxidant activity is very similar to that exerted by Ca stearate. Moreover, the VE and FA at high concentrations can be considered as suitable eco-friendly pro-degradant additives for PE, also in order to control the polyolefin degradation times.

scholarly journals Influence of High-Concentration LLDPE on the Manufacturing Process and Morphology of Pitch/LLDPE Fibres

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1099
Author(s):  
Salem Mohammed Aldosari ◽  
Muhammad A. Khan ◽  
Sameer Rahatekar
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Modulus ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
High Concentration ◽  
Scanning Electron Microscope Study ◽  
High Concentrations ◽  
Thermal Stability Of

A high modulus of elasticity is a distinctive feature of carbon fibres produced from mesophase pitch. In this work, we expand our previous study of pitch/linear low-density polyethylene blend fibres, increasing the concentration of the linear low-density polyethylene in the blend into the range of from 30 to 90 wt%. A scanning electron microscope study showed two distinct phases in the fibres: one linear low-density polyethylene, and the other pitch fibre. Unique morphologies of the blend were observed. They ranged from continuous microfibres of pitch embedded in linear low-density polyethylene (occurring at high concentrations of pitch) to a discontinuous region showing the presence of spherical pitch nodules (at high concentrations of linear low-density polyethylene). The corresponding mechanical properties—such as tensile strength, tensile modulus, and strain at failure—of different concentrations of linear low-density polyethylene in the pitch fibre were measured and are reported here. Thermogravimetric analysis was used to investigate how the increased linear low-density polyethylene content affected the thermal stability of linear low-density polyethylene/pitch fibres. It is shown that selecting appropriate linear low-density polyethylene concentrations is required, depending on the requirement of thermal stability and mechanical properties of the fibres. Our study offers new and useful guidance to the scientific community to help select the appropriate combinations of linear low-density polyethylene/pitch blend concentrations based on the required mechanical property and thermal stability of the fibres.

scholarly journals Structure and electrophysical properties of composite materials based on vacuum residue and low density polyethylene

2019 ◽  
pp. 3-5
Author(s):  
M. Yu. Dolomatov ◽  
A. M. Petrov ◽  
R. Z. Bakhtizin ◽  
O. L. Ryzhikov
Keyword(s):  
Electrical Conductivity ◽  
Composite Materials ◽  
Structural Heterogeneity ◽  
Low Density Polyethylene ◽  
Specific Electrical Conductivity ◽  
Low Density ◽  
Vacuum Residue ◽  
Electrophysical Properties ◽  
Properties Of Composites

The structure and specific electrical conductivity of composite materials based on vacuum residue and low density polyethylene has been studied. It is shown that changes in the properties of composites correspond to changes in the degree of structural heterogeneity.

Transient behavior of electrical conductivity in low‐density polyethylene in the presence of acetophenone

2021 ◽  
pp. 51881
Author(s):  
Hossein Hamedi ◽  
Roger C. Walker ◽  
W. H. Hunter Woodward ◽  
Ramakrishnan Rajagopalan ◽  
Eugene Furman ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Transient Behavior ◽  
Low Density Polyethylene ◽  
Low Density

Optimization of the cellular morphology of biaxially stretched thin polyethylene foams produced by extrusion film blowing

2018 ◽  
Vol 37 (4-6) ◽  
pp. 153-168 ◽  
Author(s):  
Ouassim Hamdi ◽  
Frej Mighri ◽  
Denis Rodrigue
Keyword(s):  
Cellular Structure ◽  
Blow Up ◽  
Nucleating Agent ◽  
Processing Parameters ◽  
Matrix Composition ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Aspect Ratios ◽  
The Matrix ◽  
A Cell

This work presents the production of cellular polymer films using extrusion blowing to impose biaxial stretching on the cellular structure while processing. The materials selected are linear low-density polyethylene (LLDPE) and low density polyethylene (LDPE) as the matrix, azodicarbonamide as the chemical blowing agent, and talc as the nucleating agent. The processing parameters, namely, the temperature profile, screw speed, feed rate, take-up ratio, blow-up ratio, and the matrix composition were all optimized to produce a homogeneous cellular structure with defined morphologies. The optimized films had a thickness below 300 µm, a relative density around 0.6, a cell density above 2 × 106 cells/cm3, and biaxially stretched cells with aspect ratios above 4 longitudinally and 3.8 transversally.

Improvement on Dispersion of Carbon Nanotubes in Polymer Matrix by Using the Solvent with a Low Boiling Point

2018 ◽  
Vol 939 ◽  
pp. 170-176
Author(s):  
Xiang Fu ◽  
Maximiano Ramos ◽  
Ahmed M. Al-Jumaily ◽  
Xi Yong Huang ◽  
Nargis Chowdhury
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Tensile Strength ◽  
Polymer Nanocomposites ◽  
Boiling Point ◽  
Dispersion Method ◽  
Evaporation Time ◽  
Excellent Performance ◽  
The Matrix ◽  
Dispersion State

Polymer nanocomposites based on carbon nanotubes attract a great deal of attention recently due to their excellent performance. The dispersion state of CNTs embedded in the matrix is the primary and key issue to realize the potential of the nanocomposite. Here, this paper considers how the boiling point of solvent affects the performance of the nanocomposite when the ultrasonication dispersion method is employed. It is found that solvent with a low boiling point is conducive to save evaporation time so that CNTs can maintain the homogenous dispersion state as much as possible after ultrasonication. Therefore, the stretchability and tensile strength can be improved, while the electrical conductivity has an obvious enhancement as well.

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