Properties Of High Density Polyethylene Research Articles

Modified lignin-based intumescent flame Retardant's effect on flame retardancy, mechanical and electrical properties of HDPE material for cable sheathing

High-density polyethylene (HDPE) is a commonly used material for cable sheathing, which is a flammable material. To ensure the safe transportation of electrical energy, it is necessary to enhance the flame-retardant properties of HDPE materials. In this work, ammonium polyphosphate (APP) with lignin (Lig) is used as an intumescent flame retardant, and the flame retardant properties of APP/Lig for HDPE with different ratios are analyzed. It is found that with 3/1 ratio of APP and Lig under 30 wt%, the best flame-retardant performance is achieved. To further improve its properties, chemical modification of Lig with hexachlorocyclotriphosphazene (HCCP) is conducted to introduce nitrogen and phosphorus, obtaining NP-Lig. Flame retardant, mechanical and electrical properties are tested for the prepared material. The flame retardant tests show that the LOI of HDPE is increased from 23.8 to 28.2 by the addition of APP/NP-Lig, compared to that of APP/Lig. Mechanical tests show that replacing Lig with NP-Lig slightly increases the tensile strength and elongation at break of HDPE. Electrical tests show that APP/NP-Lig flame retardant maintains the electrical properties of HDPE under the industry standards.

The Effect of Tool Rotational Speed and Welding Configuration on the Mechanical Properties of High Density Polyethylene (HDPE) Plate Friction Stir Welded Joint

The study investigates the impact of tool rotational speed and welding configuration on the mechanical properties of friction stir welded joints of HDPE plates. The plates were cut into rectangular shapes and clamped on a metal plate for FSW welding. Two welding configurations were used: single-side welding (SS) and double-side welding (DS), with rotational speeds of 900, 1500, and 2000 rpm. The plates were subjected to tensile and bending tests, and angular distortion was also measured. The findings suggest that decreasing the tool's rotational speed to 900 rpm and using double-side welding reduces angular distortion and improves tensile and flexural strength. The study emphasizes the importance of defect reduction techniques in improving the mechanical properties of HDPE FSW joints.

Effect of carbon black incorporation methods on the initial creep/slow crack growth resistance and properties of high-density polyethylene (HDPE) pipes

The increasing utilization of polyethylene (PE) pipes in diverse industries has driven a focused exploration into the properties and behaviors of PE materials. In response to this heightened interest, this study aims to investigate the impact of different carbon black (CB) incorporation methods on the properties of PE100 polyethylene, particularly its resistance to slow crack growth (SCG). Two distinct methods, direct incorporation and utilization of a commercial masterbatch, were employed to introduce CB into the PE100 matrix. Results revealed that direct incorporation led to superior dispersion of CB, thereby enhancing the mechanical properties of the resultant compound. Furthermore, SCG resistance exhibited improvement when CB was directly incorporated, contrasting with a degradation in SCG resistance observed when a CB masterbatch was used compared to neat PE. Comprehensive rheological and thermal analyses were conducted to elucidate these findings. The study concludes that the presence of low molecular weight substances and inadequate CB dispersion within the CB masterbatch significantly contributed to the deteriorated SCG resistance observed in PE100 material.

Zinc Oxide Filler Effect on Dissipation Factor of High-Density Polyethylene

Polymer Nano-composites (PNC) are efficient materials that consist of polymer matrix and nanoparticles to create a new generation with excellent properties. In this paper a PNC filler-based Zinc oxide (ZnO) is used for enhancing the dissipation factor (DF) or Tan δ of the obtained polymer compared to the individual polymer material and improving the electrical properties of high-density polyethylene (HDPE). The electrical properties of HDPE are investigated under different concentrations of zinc oxide including (0, 10, 20, 30, and 40 wt.%) as well as under different conditions including the variations of temperature (25-150 Celsius) and frequencies (0.1 kHz to 1 MHz). The simulation results reveal that inclusion Zinc oxide as filler can improve the electrical properties of HDPE. In addition to that the minimum value of dissipation factor and the best electrical properties can be obtained at concentration 10 % loading compared to the other concentration levels. Curve fitting solutions were performed to determine the best fit for the experimental results. African Vultures Optimization Algorithm (AVOA) was used to determine the optimal value of zinc oxide filler percentage to obtain the best optimal value of dissipation factor.

Influence of trimodal polymerization on melt rheology, thermal, and mechanical properties of HDPE resin

AbstractTrimodal polymerization of polyethylene has become a research interest in recent years due to its excellent potential for altering material properties and overcoming the limitations of the bimodal process. Here, we have comprehensively investigated the effects of manipulating polymerization parameters, such as split value (SV), hydrogen‐to‐ethylene ratio (H2/C2), and stage switching, on the rheological, thermal, and mechanical properties of synthesized trimodal high‐density polyethylene (HDPE). The synthesized samples were obtained through three consecutive stages in a slurry lab‐scale reactor. The results of molten state analysis demonstrate that recipe modification, particularly SV and H2/C2 balancing in the second and third stages, had a dramatic effect on the rheological properties including dynamic moduli, G′‐G″ crossover, and the shear‐thinning behavior. Concurrently, improvements in physio‐mechanical properties, such as sagging behavior and slow crack growth resistance (SCG), were observed compared to the bimodal resin. The thermal characterization indicates that the polymerization adjustments made did not notably impact the thermal properties of HDPE samples (e.g., Tm), throughout the all‐recipe manipulation. However, minor fluctuations in crystallinity and crystallization kinetics were observed which was presumably attributed to the molecular weight of the final resin. Overall, in our trimodal polymerization recipe, the HDPE powder is within the specified range of particle size distribution, which ensures excellent bulk density and flowability.Highlights Influence of polymerization parameters such as split value, H2/C2, and stage switching in properties of trimodal HDPE. HDPE resin received from split value and H2/C2 balancing have superior SCG and sagging resistance. All HDPE samples synthesized by different recipes have similar thermal properties.

Multifunctional HDPE/Cu biocidal nanocomposites for MEX additive manufactured parts: Perspectives for the defense industry

In this study, we investigated the performance improvement caused by the addition of copper (Cu) nanoparticles to high-density polyethylene (HDPE) matrix material. Composite materials, with filler percentages of 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0 wt% were synthesized through the material extrusion (MEX) 3D printing technique. The synthesized nanocomposite filaments were utilized for the manufacturing of specimens suitable for the experimental procedure that followed. Hence, we were able to systematically investigate their tensile, flexural, impact, and microhardness properties through various mechanical tests that were conducted according to the corresponding standards. Broadband Dielectric Spectroscopy was used to investigate the electrical/dielectric properties of the composites. Moreover, by employing means of Raman spectroscopy and thermogravimetric analysis (TGA) we were also able to further investigate their vibrational, structural, and thermal properties. Concomitantly, means of scanning electron microscopy (SEM), as well as atomic force microscopy (AFM), were used for the examination of the morphological and structural characteristics of the synthesized specimens, while energy-dispersive X-ray spectroscopy (EDS) was also performed in order to receive a more detailed picture on the structural characteristics of the various synthesized composites. The corresponding nanomaterials were also assessed for their antibacterial properties regarding Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with the assistance of a method named screening agar well diffusion. The results showed that the mechanical properties of HDPE benefited from the utilization of Cu as a filler, as they showed a notable improvement. The specimen of HDPE/Cu 4.0 wt% was the one that presented the highest levels of reinforcement in four out of the seven tested mechanical properties (for example, it exhibited a 36.7% improvement in the flexural strength, compared to the pure matrix). At the same time, the nanocomposites were efficient against the S. aureus bacterium and less efficient against the E. coli bacterium. The use of such multi-functional, robust nanocomposites in MEX 3D printing is positively impacting applications in various fields, most notably in the defense and security sectors. The latter becomes increasingly important if one takes into account that most firearms encompass various polymeric parts that require robustness and improved mechanical properties, while at the same time keeping the risk of spreading various infectious microorganisms at a bare minimum.

Investigation of the usability of laurel waste in thermoplastic composite production

In this study, the usability of laurel waste in thermoplastic composite production was investigated. After the laurel branch waste and leaf waste were ground and sieved, they were added to high-density polyethylene (HDPE) at a rate of 0-10-20-40% by weight and mixed in an extruder. Then, boards with dimensions of 250x250x3 mm were produced from the mixtures according to the hot press molding technique. As a result of adding branch and leaf flour to neat HDPE, tensile strength decreased. The tensile strength was determined as 22.28 MPa in the HDPE board and 8.6 MPa in the 40% leaf flour added board. As a result of adding branch and leaf flour to neat HDPE, bending strength first increased and then decreased. The highest flexural strength was determined as 30.3 MPa with 10% leaf flour additive, and the lowest bending strength was determined as 21.68 MPa with 40% leaf flour additive. According to Shore D test results, branch flour and leaf flour increased the hardness of neat HDPE. According to the thermal analysis results, it was seen that the effect of branch flour and leaf flour on the thermal properties of HDPE was limited. In addition, scanning electron microscope (SEM) images showed that HDPE and branch flour mixed better.

An energy storage composite using cellulose grafted polyethylene glycol as solid–solid phase change material

AbstractPhase‐change material (PCM) has great thermal energy ability, which has been used as building material for energy conservation. While the most widely used solid–liquid PCM usually appeared leakage during the phase change transition. In order to overcome the leakage of solid–liquid PCM and prepare a viable building energy‐saving materials for indoor temperature regulation, thermal energy storage composites were prepared by utilizing cellulose grafted PEG as phase change material (PCM) and high‐density polyethylene (HDPE) as the substrate. The liquid leakage of PEG was solved after graft to fabricate solid–solid PCM. HDPE is beneficial for solving the leakage and improving the mechanical property by its secondary encapsulation. The synthesized Cellulose‐PEG was characterized by scanning electron microscopy (SEM), X‐ray diffractometer (XRD), and differential scanning calorimetry (DSC). Thermal and mechanical characteristics of the composite were explored. The outcomes revealed that: (1) PEG was successfully grafted to the surface of cellulose and Cellulose‐PEG showed solid–solid phase change behavior. (2) Both the melting‐cooling temperatures and the thermal stability of solid–solid wood plastic composite (SSWPC) had the potential as thermal energy storage material for temperature regulating. (3) The addition of Cellulose‐PEG adversely affected moisture resistance, flexural property, and impact strength due to the weak interface bonding. The physical and mechanical degradation was tolerable for applying situation where mechanical performance is less crucial.Highlights Cellulose‐PEG showed solid–solid phase change behavior without liquid leakage. High‐density polyethylene (HDPE) was used as the matrix to realize the second encapsulation of PCM. Cellulose‐PEG negatively influenced the physical and mechanical property of HDPE. Solid–solid wood plastic composite presented great thermal storage capacity for indoor temperature regulating.

Morphology and Mechanical Properties of High Density Polyethylene and Ethylene-Methyl Acrylate Copolymer Blends with Organoclay

In this research, the effect of ethylene-methyl acrylate copolymer (EMAC or EMAC30) and clay surface modified with aminopropyltriethoxysilane 0.5-5 wt% and octadecylamine 15-35 wt% (Clay-ASO) on the morphological, mechanical, and thermal properties of high density polyethylene (HDPE) were investigated. The polymer blends and composites were prepared by an internal mixer and then samples were molded by compression molding. The morphology analysis showed that the presence of fibrous surface at the specimen fracture surface of HDPE/EMAC30 blends. The phase morphology of HDPE blends with Clay-ASO 3, 5 and 7 phr was observed the phase separation of EMAC30 and aggregate of Clay-ASO at high EMAC30 content. Young’s modulus of HDPE/Clay-ASO composites increased with increasing Clay-ASO composites. The presence of Clay-ASO did not improve Young’s modulus and tensile strength of HDPE/EMAC30/Clay-ASO composites. The strain at break of HDPE/EMAC30 blends increased with increasing EMAC30 content. The incorporation of EMAC30 and Clay-ASO had no effect on the melting temperature of HDPE blends and composites, respectively. The percent crystallinity of HDPE/EMAC30 and HDPE/EMAC30/Clay-ASO was lower than that of pure HDPE. The addition of EMAC30 and Clay-ASO decreased the degradation temperatures of HDPE/EMAC30 blends and composites.

The effect of chemical crosslinking on the properties of Rotomolded high density polyethylene

AbstractIn this study, high density polyethylene (HDPE) was combined with dicumyl peroxide (DCP) to produce crosslinked parts via rotational molding. The effect of DCP content (0.1–2.5 phr) on the crosslinking degree was investigated to determine its effect on the chemical, mechanical, physical, and thermal properties of HDPE. The gel content and crosslink density was found to increase with DCP content. These trends led to a reduction in the degree of crystallinity, melting, and crystallization temperature. Thermogravimetric analysis (TGA) showed that crosslinked HDPE (xHDPE) has higher thermal stability than the neat matrix in both air and nitrogen atmosphere. In addition, a direct relationship was observed between improved thermal resistance and higher impact strength. Finally, relationships between the tensile properties of xHDPE and the degree of crystallinity were observed, which were all controlled by the level of crosslinking. These results have the potential to advance the manufacturing of high performance materials suitable for a wide range of applications such as automotive parts, agricultural products, chemical storage tanks, large waste containers, and fuel tanks in general.

Effect of Mass and Temperature Rate on the Thermal Properties of High-Density Polyethylene Using Differential Scanning Calorimetry

Mass and heating rates alter the thermal properties, molecular structure, and phase changes of the materials. This study aimed to investigate the influence of sample mass (10-30 mg) and heating rate (4-15 °C/min) on the thermal characteristics of high-density polyethylene (HDPE) using differential scanning calorimetry (DSC). The experiments were conducted in two cycles. In the first cycle, samples of different masses (10-30 mg) were heated to 180 °C followed by cooling at a constant heating rate of 10 °C/min with a mass flow rate of 20 ml/min of purging gas (nitrogen). In the second cycle, a sample mass of 15 mg was used to investigate the thermal characteristics while varying the temperature rates (4, 6, 8, 10, and 15 °C/min). It was concluded that the variation in sample mass significantly affected the thermal properties of HDPE, leading to a slight increase in the melting temperature and latent heat, which shifted towards higher temperatures. In contrast, the temperature rate caused a reduction in the latent heat and crystallization temperatures. The thermograms obtained from the experiments provided insight into the thermal behavior of HDPE under different conditions, and the findings emphasized the importance of carefully considering the effects of mass and temperature rate when measuring the thermal properties of HDPE.

Radiation attenuation properties of chemically prepared MgO nanoparticles/HDPE composites

Sheets of high-density polyethylene (HDPE) loaded with magnesium oxide in micro and nano were synthesized with different weight percentages of micro-MgO (0,5,10,20 and 30% by weight) and nano-MgO (5 and 30%) and shaped in form of disc and dog bone shape. The morphological, mechanical, and attenuation characteristics of each concentration were determined. The linear attenuation coefficients (LAC) of the prepared discs were calculated using a well-calibrated scintillation detector and five standard gamma-ray point sources (241Am, 133Ba, 137Cs, 60Co and 152Eu). The LAC was theoretically calculated for HDPE/micro-MgO composites using XCOM software. A good agreement between the theoretical and experimental results was observed. The comparison between micro and nano-MgO as a filler in HDPE was evaluated. The results proved that the loaded nano-MgO in different proportions of HDPE produced greater attenuation coefficients than its micro counterpart. The addition of nano MgO with different weight percentage led to a significant improvement in the mechanical properties of HDPE, the ultimate force and ultimate stress increased as the concentration of nano MgO increased, and the young modulus of HDPE also increased with increasing concentration of micro and nano MgO.

Degradation of high density polyethylene packaging by accelerated aging in sea water

AbstractThe increase of plastic waste in the marine environment raises several ecological, human, and biological problems. In this work, an accelerated artificial aging study was conducted in seawater after immersing samples of high‐density polyethylene bottles for several aging times and at three different temperatures. The deterioration of the mechanical properties of High density polyethylene (HDPE) under different aging conditions was investigated using tensile and compression tests. The absorption of seawater by the samples was analyzed using a gravimetric method and Fourier transform infrared spectrometry (FTIR). Further surface analysis of the samples during accelerated aging was performed using a scanning electron microscope. The results show that HDPE loses its ductility and rigidity. FTIR analysis confirms the increase in crystallinity during aging.

Effect of oil palm boiler ash modified with PEG 6000 on mechanical properties of high density polyethylene

The mechanical properties of material play an essential role in the material. Mechanical properties are one of the properties possessed by a material to function for various applications. Using nanostructured materials such as silica and layered silicates as fillers can significantly change the properties of the polymer matrix. OPBA preparation was carried out using calcination and ball mill methods, coprecipitation, and the addition of PEG 6000. Various methods were carried out to obtain OPBA with optimal silica content. HDPE thermoplastic was prepared with OPBA filler by mixing HDPE thermoplastic with OPBA nanoparticles modified with PEG 6000. SEM OPBA calcination and ball mill show the presence of pores on the surface. Meanwhile, the pore in OPBA does not lead to coprecipitation. However, in OPBA with added PEG 6000, it was seen again that there were pores on the surface and the presence of agglomerate dispersions in OPBA preparation with PEG 6000 showed the addition of functional groups to OPBA. The dispersion peaks of the silica contained in OPBA with state characteristics at 20o–30o appear in the XRD patterns of unmodified silica and modified silica, indicating that the precipitated silica is amorphous silica and the surface modification does not change the phase structure of the modified silica. In addition, the optimal silica content is found in OPBA PEG 6000, with a silica content of 60.7%. The addition of OPBA PEG 6000 filler generally increases the mechanical properties of tensile strength, elongation at break, and elongation modulus.

Investigation on Constitutive and Ductile Damage Mechanism of High-Density Polyethylene under Tensile and Bending Conditions

High-density polyethylene (HDPE) is one of the most commonly used materials for manufacturing pipelines. In this paper, the deformation behavior of HDPE materials under uniaxial tensile stress was investigated by employing uniaxial tensile tests and macroscale/mesoscale morphology analysis. The experimental results indicated that the stress–strain relationship of HDPE is nonlinear, and the ductile fracture characteristics of necking and local failure appear in the sample after the engineering strain reaches 35%. Therefore, for the first time, a hyperelastoplastic constitutive model that describes the elasticity by the Marlow model and combined the isotropic plasticity-ductility damage correction is established, and a corresponding numerical approach is proposed. The simulation scheme was implemented in finite-element software, and the mechanical responses of HDPE under uniaxial tensile and bending loads were predicted. Obtained calculations were relatively consistent with experimental observations. Hence, the proposed model and approach have a good simulation effect on the mechanical properties of HDPE and can be employed for the process prediction of such materials. This study is beneficial to the in-depth understanding of the hyperelastoplasticity and failure mechanism of HDPE and provides ideas for the deformation and failure study of other polymer materials.

Evaluating the Integrity of High-Density Polyethylene Storage Tanks

Failure of high-density polyethylene (HDPE) aboveground storage tanks (ASTs) causes numerous environmental, ecological, and economic problems. Therefore, it is necessary to routinely inspect the integrity of ASTs to identify the potential defects and act before a catastrophic failure happens. This study investigated the feasibility of using infrared thermography (IRT) for routine HDPE AST inspections and how weathering impacts the properties of HDPE. Moreover, the factors affecting the IRT’s accuracy for defect detection were researched, and it was attempted to determine the minimum levels of defect detection for each weather circumstance. This study investigated the potential areas for tank failure for close inspection. Results showed that IRT is efficient in detecting shallow defects within the outer half of the wall. The smallest detectable defect size was 2.8 mm, which varied in different measurements depending on the interaction of sample geometry, initial thermal gradient, and defect location.

The Effect of Graphene on the Mechanical Properties of High Density Polyethylene (HDPE)/Zinc Borate Polymer Composite

Bu çalışmada; yüksek yoğunluklu polietilen (YYPE) içerisine %5 oranında çinko borat ve farklı oranlarda grafen tozları katılarak bir kompozit üretilmiştir. Kompoziti oluşturan malzemeler çift vidalı ekstrüzyon makinesinde karıştırılarak beş farklı grup elde edilmiştir ve enjeksiyon makinası kullanılarak standart test numuneleri üretilmiştir. Mekanik değerleri belirlemek için çekme, sertlik ve darbe testleri yapılmıştır. Ayrıca çinko borat ve grafenin dağılımlarını belirlemek için taramalı elektron mikroskobisi (SEM) ile fotoğrafları çekilmiştir. Analizler sonucunda YYPE içerisinde çinko borat ve grafen toz ilavesiyle; elastiklik modülü, çekme mukavemeti, kopma mukavemeti ve sertlik değerlerinin arttığı diğer taraftan darbe mukavemeti kopma uzaması ve kopma uzaması değerlerinin ise düştüğü tespit edilmiştir. SEM inceleme sonucu çinko borat ve grafen tozlarının homojen dağıldığı tespit edilmiştir.

Effect of functionalized graphene addition on mechanical and thermal properties of high density polyethylene

Abstract High density polyethylene (HDPE)/graphene nanocomposites were successfully synthesized by compounding of HDPE, as polymer matrix, with hexamethylenediamine functionalized graphene. The resulting nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and thermal gravimetric analysis (TGA) techniques. SEM characterization confirmed the good dispersion (homogeneous and uniform) of graphene in the polyethylene matrix. The TGA technique revealed a slight improvement in thermal resistance. Functionalized graphene improved a better thermal stability of HDPE (up to 6 °C) than non-functionalized graphene (up to 2 °C). Mechanical tensile and torsion tests showed that HDPE/functionalized graphene nanocomposites exhibit high tensile strength and low torsional strength compared to HDPE/non-functionalized graphene nanocomposites. Compared to pure HDPE, the Young’s modulus increased by 80% and 30%, whereas, the torsion modulus increased by about 34% and 44% for the HDPE/functionalized and HDPE/non-functionalized graphene, respectively. Regardless of this increase, it can be seen that the torsion modulus of HDPE/non-functionalized graphene is much higher than that of HDPE/functionalized graphene.

Additive Effects of Solid Paraffins on Mechanical Properties of High-Density Polyethylene

In this work, two types of solid paraffins (i.e., linear and branched) were added to high-density polyethylene (HDPE) to investigate their effects on the dynamic viscoelasticity and tensile properties of HDPE. The linear and branched paraffins exhibited high and low crystallizability, respectively. The spherulitic structure and crystalline lattice of HDPE are almost independent of the addition of these solid paraffins. The linear paraffin in the HDPE blends exhibited a melting point at 70 °C in addition to the melting point of HDPE, whereas the branched paraffins showed no melting point in the HDPE blend. Furthermore, the dynamic mechanical spectra of the HDPE/paraffin blends exhibited a novel relaxation between -50 °C and 0 °C, which was absent in HDPE. Adding linear paraffin toughened the stress-strain behavior of HDPE by forming crystallized domains in the HDPE matrix. In contrast, branched paraffins with lower crystallizability compared to linear paraffin softened the stress-strain behavior of HDPE by incorporating them into its amorphous layer. The mechanical properties of polyethylene-based polymeric materials were found to be controlled by selectively adding solid paraffins with different structural architectures and crystallinities.

Assessing the weathering-induced degradation on the structural integrity of high-density polyethylene

Marine plastic pollution is a growing environmental concern, with plastic debris in the ocean having negative impacts on marine life and human health. One of the major challenges in addressing this problem is the slow degradation rate of plastics in the marine environment. In this study, the degradation of high-density polyethylene (HDPE), being extremely common in marine debris, is investigated when exposed to either (a) marine or (b) atmospheric environmental exposure. The weathering effects for this type of plastic were examined through ultraviolet spectrophotometer and tensile investigations. A chain-breaking activity in the microstructure of the weathered HDPE specimens was revealed. During the investigated eight (8) months of atmospheric and sea weathering, an approximate 10 % and 6 % decrease in ultimate tensile strength σUTS was noticed for the two different environments, respectively. Higher decrease was noticed for the respective elastic modulus E (Young’s modulus) that was approximate 23 % and 21 %, respectively. Based on the available experimental test results, a linear decrease rate equation of all the investigated mechanical properties was proposed, to give valuable information regarding the residual tensile mechanical properties of HDPE after weathering exposure.