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This paper presents the obtaining and characterization of blends based on high-density polyethylene (HDPE) and plasticized starch. In addition to plasticized starch (28.8% w/w), the compositions made also contained other ingredients, such as polyethylene-graft-maleic anhydride as a compatibilizer, ethylene propylene terpolymer elastomer, cross-linking agents, and nanoclay. Plasticized starch contains 68.6% w/w potato starch, 29.4% w/w glycerin, and 2% w/w anhydrous citric acid. Blends based on HDPE and plasticized starch were made in a Brabender Plasti-Corder internal mixer at 160 °C, and plates for testing were obtained using the compression method. Thermal analyses indicate an increase in the crystallization degree of the HDPE after the addition of plasticized starch. SEM micrographs indicate that blends are compatibilized, with the plasticized starch being well dispersed as droplets in the HDPE matrix. Samples show high hardness values (62–65° ShD), good tensile strength values (14.88–17.02 N/mm2), and Charpy impact strength values (1.08–2.27 kJ/m2 on notched samples, and 7.96–20.29 kJ/m2 on unnotched samples). After 72 h of water immersion at room temperature, mixtures containing a compatibilizer had a mass variation below 1% and water absorption values below 1.7%. Upon increasing the water immersion temperature to 80 °C, the sample without the compatibilizer showed a mass reduction of −2.23%, indicating the dissolution of the plasticized starch in the water. The samples containing the compatibilizer had a mass variation of max 8.33% and a water absorption of max 5.02%. After toluene immersion for 72 h at room temperature, mass variation was below 8%. [ABSTRACT FROM AUTHOR]

Metallization of polymers is a modern technique used to improve their properties by coating them with conductive, lightweight surfaces, enabling their use in many electronic and communications applications. This study examines the effect of corrosion of a copper layer deposited on two polymeric substrates, high-density polyethylene (HDPE) and acrylonitrile butadiene styrene (ABS), by flame thermal spraying. Pull off test shows the adhesion strengths between the Cu coating layers and the HDPE and ABS substrates were 1.42 and 1.94 MPa, respectively. The contact angles for the HDPE and ABS were 57.227 and 36.422ο, respectively, indicating that the ABS substrate is more wettable than the HDPE substrate. A corrosion test of the coated substrates was conducted at 27±1 °C in a solution of 3.5% NaCl. The corrosion rate was 2.763×10-2 mm/year for Cu on HDPE and 1.361×10-2 mm/year for Cu on ABS. The corrosion rate of Cu on HDPE is greater than that of Cu on ABS, indicating that the Cu coating layer on the ABS substrate is denser and less porous than that on the HDPE substrate. The corrosion products for the corroded Cu layer on HDPE were NaCl, NaOH, Cu5Zn8 and CuCl, whereas those for the corroded Cu on ABS were CuCl and Cu(OH)2. [ABSTRACT FROM AUTHOR]

The effect of thermal-oxidative ageing on in-isolation and in-soil stiffness is investigated for two high-density polyethylene (HDPE) and two polyester (PET) geogrids when incubated in an oven at 90°C. It is shown that the in-isolation and in-soil stiffness of three out of the four geogrids decreased during the 4-month ageing time with a faster degradation of the two PET geogrids. In contrast, one of the HDPE geogrids examined with thicker rib showed slower degradation compared to the PET counterparts. It is also shown that a geogrid might have a higher unaged stiffness, but less aged stiffness compared to another geogrid made of the same polymer type. It is suggested that the ageing approach used in this study could be adopted for the selection of geogrids based on their long-term stiffness for structures such as reinforced embankments or mechanically stabilized earth walls that require a long service life. Moreover, results indicate that the stiffness improvement factor for PET geogrids decreases with ageing time. On the contrary, the stiffness improvement factor of the HDPE geogrid increases with time and hypothetically might keep increasing followed by a sudden drop to zero at full degradation of the geogrid. [ABSTRACT FROM AUTHOR]

Plastic pollution is a critical environmental issue due to the widespread use of plastic materials and their long degradation time. Hydrocracking (HDC) offers a promising solution to manage plastic waste by converting it into valuable products, namely chemicals or fuels. This work aims to investigates the effect of catalyst accessibility and acidity on the HDC reaction of high density polyethylene (HDPE). Therefore, a variety of materials with significant differences in both textural and acidic properties were tested as catalysts. These include H-USY and H-ZSM.5 zeolites with various Si/Al molar ratios (H-USY: Si/Al = 2.9, 15, 30 and 40; H-ZSM-5: Si/Al = 11.5, 40, 500) and mesostructured MCM-41 materials modified with Ga and Al, also with different Si/metal ratios (Si/Al = 16 and 30; Si/Ga = 63 and 82). Thermogravimetric analysis under hydrogen atmosphere was used as a preliminary screening tool to evaluate the potential of the various catalysts for this application in terms of energy requirements. In addition, batch autoclave reactor experiments (T = 300 °C, PH2 = 20 bar, t = 60 min) were conducted to obtain further information on conversion, product yields and product distribution for the most promising systems. The results show that the catalytic performance in HDPE hydrocracking is determined by a balance between the acidity of the catalyst and its structural accessibility. Accordingly, for catalyst series where the structural and textural properties do not vary with the Si/Al ratio, there is a clear correlation of the HDPE degradation temperature and of the HDPE conversion with the Si/metal ratio (which relates to the acidic properties). In contrast, for catalyst series where the structural and textural properties vary with the Si/Al ratio, no consistent trend is observed and the catalytic performance is determined by a balance between the acidic and textural properties. The product distribution was also found to be influenced by the physical and chemical properties of the catalyst. Catalysts with strong acidity and smaller pores were observed to favor the formation of lighter hydrocarbons. In addition to the textural and acidic properties of the catalyst, the role of coke formation should not be neglected to ensure a comprehensive analysis of the catalytic performance. [ABSTRACT FROM AUTHOR]

The effects of 1.75 MeV N5+ ion beam irradiation of varying ion fluences, ranging from 1 × 1012 to 3 × 1014 ions/cm2, on high-density polyethylene have been done to investigate the structural, optical and chemical properties using X-ray diffraction (XRD), UV–visible spectroscopy and Fourier transform infrared (FTIR) spectroscopic techniques. XRD patterns show no significant change in crystallinity in irradiated polymer samples. The lattice plane and crystallite size of the irradiated polymer have not changed noticeably. More than 50% decrease in optical band gap were found for higher ion fluences of 3 × 1014 ions/cm2. UV–visible spectra show a red shift in absorption maxima due to the formation of extended conjugation. FTIR peaks 3646, 1707 and 2170 cm−1 in irradiated polymer were observed. The reaction mechanism chemistry of radiation-induced product formations, including chain scission, molecular crosslinking and hydroxyl, carbonyl and alkyne functional groups have been discussed. [ABSTRACT FROM AUTHOR]

Plastic recycling, waste minimization such as process outfall valorization promotes a circular economy. Herein, food trays have been produced in the moulded pulp thermoforming process. To this end, high-density polyethylene (HDPE) outfall has been dispersed in water via Poly vinyl alcohol (PVA) addition in a Northern Bleached Softwood Kraft Pulp (NBSKP) slurry. Samples physical and mechanical properties have been evaluated. With an increasing HDPE content, parts air permeability was drastically reduced to a minimum of 2.4 ± 0.8 mL min−1. In addition, water and grease hold out properties have been increased with minimum water Cobb1800 value of 10.9 ± 5.4 gm−2 and oil Cobb1800 value of 13.18 ± 6.5 gm−2. Samples with high HDPE content demonstrated hydrophobic surface with water contact angle value above 90°. HDPE melting and binding to wood pulp fibers was monitored by SEM images. Regarding the mechanical properties, HDPE induced plastic deformation with a reduced Young modulus by 17 %. Moreover, the addition of HDPE increased wet strength by 81 %. However, the produced food tray composites with high HDPE content demonstrated low repulpability index. [ABSTRACT FROM AUTHOR]

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This research investigates the microbial degradation of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) plastics by Bacillus sp., Proteus sp., Pseudomonas sp., and Salmonella sp. The study employs a systematic approach, isolating microorganisms from plastic-contaminated soil and subjecting them to a series of biochemical tests for identification. The research evaluates the weight loss of LDPE and HDPE over two months, revealing varying degrees of degradation among the bacterial strains. Results suggest a potential greater susceptibility of HDPE to microbial degradation. Scanning Electron Microscopy (SEM) analysis provides high-resolution images of the plastic surface, indicating structural changes and biofilm formation during degradation. The findings highlight the unique enzymatic capabilities of each strain and underscore the significance of SEM in elucidating microbial interactions with plastics. The study prompts discussions on optimization, synergistic effects, and the identification of key enzymes in plastic degradation, emphasizing the importance of microbial strategies for waste management. Overall, this research contributes valuable insights into the potential of bacterial strains for addressing plastic pollution challenges. [ABSTRACT FROM AUTHOR]

Bone tissue engineering (BTE) applications and regenerative strategies have been used to improve the clinical practice of repairing large bone defects associated with surgical resections, congenital malformations, and trauma. The scaffolds are designed to stimulate a biological response, including cell interactions, and guide tissue regeneration by functioning as artificial biomimetic extracellular matrixes. Polymeric biomaterials are suitable for bone tissue engineering since they possess both chemical and physical properties, enabling the control of shape, morphology, and biodegradability, which makes them suitable for bone regeneration and tissue engineering applications. In vivo animal models were studied for collagen, chitosan, poly (lactic acid) (PLA) and high density polyethylene (HDPE), the four most common polymers employed in bone tissue engineering. Through analysis of the results of this review, the in vivo studies can provide a large-scale evaluation of the possibility of achieving optimal bone-forming capabilities and regenerative capabilities. Furthermore, the review will serve as an essential reference for bone tissue engineering applications as well as contribute to the development of novel in vivo investigations [ABSTRACT FROM AUTHOR]

In this research, the performance of asphalt mixtures modified with polyethylene polymer (PE) by adding 2%, 4%, and 6% percentages was evaluated. Two kinds of PE are employed: Low-Density PE (LDPE) and High-Density PE (HDPE). The semi-wet mixing technique (SWM) was conducted to avoid stability issue for PE-modified binder during storage condition. Many experimental tests were conducted to evaluate the ability of these mixtures to withstand the effects of loads and moisture. The hardness index of these mixtures was also measured to determine their resistance to the effects of high temperatures without causing permanent deformations. The results showed that adding PE led to a remarkable enhancement in the performance of PE-modified mixtures. The improvement in stability reached 113.36% when using HDPE and it was 86.19% for LDPE. For moisture resistance, it improved by 10.42% and 9.91% when using HDPE and LDPE, respectively. The modified mixtures also showed higher hardness index compared to the standard mixture. According to the outcomes of this research, it can be concluded that the optimum percentage for using PE polymer as a modifier in bitumen is 6% and HDPE is more effective than LDPE. Overall, the SWM is easier and more economical compared to the wet mixing. [ABSTRACT FROM AUTHOR]

The stress crack resistance (SCR) of high-density polyethylene (HDPE) geomembrane extrusion welds is examined for a 1.5 mm HDPE geomembrane and three different welding parameter combinations (denoted as "Cool", "Good", and "Overheated"). Results are reported for unnotched welds, unnotched sheet, and notched sheet. The average SCR for a Good extrusion weld is 23% of that of the unnotched sheet SCR. Little variation is found between the three welding parameter combinations for low geometry irregularity SCR weld specimens. There is no statistically significant difference between a good-quality fusion and extrusion weld. However, operator-dependent weld induced geometric irregularity (WIGI) greatly affects the SCR of extrusion welds. Extrusion welds with high WIGI have an average unnotched SCR of only 9% of the unnotched sheet. Extrusion welds with an overground surface can have an unnotched SCR as little as 1% of the best extrusion weld. Deleterious weld bead geometries are identified to provide a framework with which engineers can identify "high-risk" extrusion welds with respect to stress cracking. • Paper highlights: • First examination of the effects of weld-induced geometric irregularity (WIGI) in extrusion welds on unnotched stress crack resistance. • Highlights the impact of poor quality control for extrusion welds (e.g., overgrinding, high WIGI, and scratches) on the likelihood of stress cracking in the field. • Demonstrates that a good extrusion weld (i.e., low WIGI, good grinding, and appropriate welding temperature) has a comparable unnotched stress crack resistance to that of a good fusion weld. • Demonstrates that the operator-dependent nature of extrusion welds substantially increases the variability in the stress crack resistance of extrusion welds compared to fusion welds. • Highlights the importance of doubling the standard oxidative induction time (Std-OIT) of welding rod to reach a post-welded bead's Std-OIT similar to the sheet's Std-OIT (i.e., it shows a 50% decrease in Std-OIT of the extruded bead compared to the initial rod entering the extruder). [ABSTRACT FROM AUTHOR]

The present work reports the application of novel gut strains Bacillus safensis CGK192 (Accession No. OM658336) and Bacillus australimaris CGK221 (Accession No. OM658338) in the biological degradation of synthetic polymer i.e., high-density polyethylene (HDPE). The biodegradation assay based on polymer weight loss was conducted under laboratory conditions for a period of 90 days along with regular evaluation of bacterial biomass in terms of total protein content and viable cells (CFU/cm2). Notably, both strains achieved significant weight reduction for HDPE films without any physical or chemical pretreatment in comparison to control. Hydrophobicity and biosurfactant characterization were also done in order to assess strains ability to form bacterial biofilm over the polymer surface. The post-degradation characterization of HDPE was also performed to confirm degradation using analytical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electronic microscopy (FE-SEM) coupled with energy dispersive X-ray (EDX), and Gas chromatography–mass spectrometry (GC–MS). Interestingly strain CGK221 was found to be more efficient in forming biofilm over polymer surface as indicated by lower half-life (i.e., 0.00032 day−1) and higher carbonyl index in comparison to strain CGK192. The findings reflect the ability of our strains to develop biofilm and introduce an oxygenic functional group into the polymer surface, thereby making it more susceptible to degradation. [ABSTRACT FROM AUTHOR]

In this work, a polymeric blend of polypropylene (PP) and high-density polyethylene (HDPE) was prepared with different weight percentages. Zinc oxide nanoparticles (ZnO) were added to the 90/10 and 80/20 blends with different weight ratios (1%, 2%, and 3%) to study their effect on both the mechanical and thermal properties of the PP/HDPE blends. A twin-screw extruder was used for the preparation of polymeric blends and their composites. Mechanical properties (tensile properties and hardness) were studied. Thermal properties using Differential Scanning Calorimetry (DSC) were investigated. Fourier transform infrared (FTIR) was used to predict the change in chemical structure. Results for PP/HDPE blends show that both tensile strength and hardness decrease as the amount of HDPE increases due to immiscibility, and these properties are improved by the addition of ZnO nanoparticles. Thermal properties from DSC show that the melting temperature Tm, crystallization temperature Tc were improved by the ZnO addition, and the degree of crystallinity improved only for the90/10 blend. FTIR shows that there is only a physical interaction, not a chemical one. [ABSTRACT FROM AUTHOR]

Mechanical properties (tensile strength (TS), modulus of elasticity in tensile (MET), flexural strength (FS), modulus of elasticity (MOE)) of the material to be obtained depending on the production parameters in the production of high-density polyethylene (HDPE) wood-polymer composites with Scots pine wood flour additive were predicted using Artificial Neural Networks (ANN) model and without destructive testing. In the first stage of the study, an ANN model was developed using data from 56 different studies in the literature on the mechanical properties of wood polymer composites. In the second stage, in order to determine the reliability of the model, output values were estimated using input parameters that had not been used in training and testing of the model. Based on the same input parameters, test specimens were produced and mechanical tests were performed. The results obtained from the experiments and ANN model were compared by considering the mean absolute percentage error (MAPE) value. The coefficient of determination (R2) values obtained in the training and testing phase of the ANN models were all higher than 0.90. In this way, the mechanical properties of the wood polymer composite were successfully predicted by the ANN model. Because most of the MAPE values obtained from the mechanical tests were below 10%, the model was considered a reliable model. [ABSTRACT FROM AUTHOR]

High-Density Polyethylene (HDPE) like other thermoplastics has low mechanical properties which limits its range of applications, especially under the influence of dynamic loads and high temperatures. Therefore, as one of the highly attractive approaches for improving mechanical properties, nanomaterials have been used as reinforcement materials in polymer matrix composite. The present study focuses on the role of nanomaterials on the mechanical properties and fatigue resistance of high-density polyethylene reinforced with (1, 2, and 3%) nano alumina oxide at a range of testing temperatures between 20 and 60ºC. The results manifested that the addition of nano alumina oxide improves the strength of base polyethylene and increases the fatigue resistance by (63.7%, 146.5%, and 228.4%), (69.25, 163.5 and 202.8) and (94%, 214.8% and 290.3) at (20. 40 and 60°C), respectively in cooperation with the pure high-density polyethylene. In addition, as the applied testing temperature increases, the fatigue resistance in all test specimens decreases. It was found that the highest fatigue resistance occurred at (HDPE+3%Al2O3) composite due to the good distribution of nano Al2O3 within the HDPE base which led to a better crack propagation prevention than other composites. [ABSTRACT FROM AUTHOR]

Microplastic pollution poses an escalating concern, particularly in coastal lagoons rich in biodiversity. This study delved into the occurrence of microplastics (MPs) in Magallana gigas (formerly Crassostrea gigas) from the Orbetello and Varano coastal lagoons (Italy), also investigating the response of these filter-feeding organisms to various colors (P = pink; B = blue; W = white) of high-density polyethylene (HDPE) MP fragments. Oysters were exposed for 7 days under controlled conditions. Subsequently, the oysters underwent analysis for both MP presence and biochemical markers of oxidative stress. Diverse ingestion rates of HDPE were noted among oysters from the two lagoons, eliciting antioxidant responses and modifying baseline activity. The two-way ANOVA revealed the significant effects of treatment (control; HDPE_B; HDPE_P; HDPE_W), site, and the interaction between treatment and site on all biomarkers. Non-metric multidimensional scaling showed a divergent effect of HDPE color on biomarkers. Further investigation is warranted to elucidate the mechanisms underlying the influence of MP color, dose-dependent effects, and the long-term impacts of exposure. Comprehending these intricacies is imperative for devising effective strategies to mitigate plastic pollution and safeguard marine health. [ABSTRACT FROM AUTHOR]

Trimodal 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. [ABSTRACT FROM AUTHOR]

Microplastic pollution is an emerging concern and poses a potential risk to soil ecosystems and subsequently can lead to groundwater contamination. The sandy and silty soils are the major soil types covering more than 31 % of the land area globally. The vertical transport of microplastic in sandy and silty soil and further possible groundwater contamination is still unclear and not fully understood in the literature. The present study focuses on the movement of High-Density Polyethylene (HDPE) microplastics in quartz sand and silty soil using column experiments. Detailed flow through laboratory experiments are performed to understand the effect of varying the critical parameters in contaminant transport such as pore volumes (1PV,2PV,3PV,4PV,5PV,6PV,7PV,8PV,9PV,10PV) and flow rates (20,40,60,80,100,120 ml/min) on HDPE microplastic movement in sandy and silty soil separately. The maximum depth of microplastic transport in sandy soil was 20-22 cm for a flow rate of 120 ml/min, and 10-12 cm for 20 ml/min. In silty soil, the maximum depth of microplastic transport was 12-14 cm for 120 ml/min and 6-8 cm for 20 ml/min. The study also estimates the number of years required for microplastic contamination to reach groundwater under field conditions by considering the L/S ratio. The study estimated that it could take 144 years for microplastics to penetrate sandy soil and 356 years for silty soil, under the study conditions. The study highlights the significant threat posed by microplastics to groundwater contamination. The results suggest that soils may serve as both a sink for microplastics and a potential pathway for their entry into subsurface environments, such as underground habitats and water sources.

High-density polyethylene (HDPE) has a higher strength-to-density ratio and stiffness but a low branching degree for the packed linear chains that restrict the ability to bond and resist cracking. This study conducts the role of inserting rigid nanoclay (NC) and soft acrylonitrile butadiene styrene (ABS) on the structural, nonlinear fracture toughness and crack resistance of a ternary HDPE/low-density polyethylene-grafted maleic anhydrite (LDPE-g-MA)/ABS blend. Varying additions of 1, 3, 5, and 7 % NC and 5, 10, 15 wt. % ABS were inserted into neat HDPE and HDPE90/LDPE-g-MA10. All materials were hand-mixed before feeding into a single screw extruder and directly melt-blended twice to achieve a good dispersion of nanofiller in the matrix. The structural characteristics and the fracture surfaces of NC/HDPE/LDPE-g-MA and NC/HDPE/LDPE-g-MA/ABS were investigated by TEM, XRD, SEM, and FTIR spectra. Tensile strength and the critical dissipated energy (JIc) determined by quasi-static J-integral fracture mechanic revealed a higher absorbing fracture energy of 75 KJ/m2 for the binary and 85 KJ/m2 for the ternary nanocomposites. The synergistic percolated role of the NC particles and ABS copolymer in front of the crack tip region hinders crack growth for the presence of micro-void coalescence and massive shear-yielding toughening mechanisms. [ABSTRACT FROM AUTHOR]

Experiments have assessed various polymer composites for radiation shielding in diverse applications. These composites are lighter and non-toxic when compared to lead (Pb), making them particularly effective in diagnostic imaging for shielding against low-energy photons. This study demonstrates the fabrication of four composites by combining a base material, specifically a high-density polyethylene (HDPE) polymer, with 10% and 20% silicon (Si) and silicon carbide (SiC), respectively. Additionally, 5% molybdenum (Mo) was incorporated into the composites as a heavy metal element. The composites obtained were fabricated into 20 disks with a uniform thickness of 2 mm each. Discs were exposed to radiation from a low-energy X-ray source (32.5–64.5 keV). The chemical and physical properties of composites were assessed. The shielding ability of samples was evaluated by determining the linear and mass attenuation coefficients (μ and μm), radiation protection efficiency (RPE), half-value layer (HVL), and mean free path (MFP). According to our findings, supplementing HDPE with additives improved the attenuation of beams. The μm values showed that composite X-ray shielding characteristics were enhanced with filler concentration for both Si and SiC. Polymer composites with micro-molecule fillers shelter X-rays better than polymers, especially at low energy. The HVL and MFB values of the filler are lower than those of the pure HDPE sample, indicating that less thickness is needed to shield at the appropriate energy. HC-20 blocked 92% of the incident beam at 32.5 keV. This study found that increasing the composite sample thickness or polymer filler percentage could shield against low-energy radiation. [ABSTRACT FROM AUTHOR]

To address the dilemma of the stiffness and toughness properties of high-density polyethylene (HDPE) composites, titanate coupling agent-treated CaCO3 nanoparticles (nano-CaCO3) and ethylene–octene copolymer (POE) were utilized to blend with HDPE to prepare ternary nanocomposites via a two-sequence-step process. Meanwhile, a one-step process was also studied as a control. The obtained ternary nanocomposites were characterized by scanning electron microscopy (SEM), Advanced Rheometrics Expansion System (ARES), Dynamic Mechanical Analysis (DMA), wide-angle X-ray diffraction analysis (WXRD), and mechanical test. The SEM results showed one or two CaCO3 nanoparticles were well-encapsulated by POE and were uniformly dispersed into the HDPE matrix to form a core–shell structure of 100–200 nm in size by the two-step process, while CaCO3 nanoparticles were aggregated in the HDPE matrix by the one-step method. The result of the XRD showed that the nano-CaCO3 particle played a role in promoting crystallization in HDPE nanocomposites. Mechanical tests showed that the synergistic effect of both the POE elastomer and CaCO3 nanoparticles should account for the balanced performance of the ternary composites. In comparison with neat HDPE, the notched impact toughness of the ternary nanocomposites of HDPE/POE/nano-CaCO3 was significantly increased. In addition, the core–shell structure absorbed the fracture impact energy and prevent further propagation of micro-cracks, thus obtaining a higher notched Izod impact strength. [ABSTRACT FROM AUTHOR]

As one of the most widely applied general-purpose plastics, high-density polyethylene (HDPE) exhibits good comprehensive performance. However, mechanical strength limits its wider application. In this work, we introduced the engineering plastic PA6 as a dispersed phase to modify the HDPE matrix and applied multiple shears generated by vibration to the polymer melt during the packing stage of injection molding. SEM, 2D-WXRD and 2D-SAXS were used to characterize the morphology and structure of the samples. The results show that under the effect of a strong shear field, the dispersed phase in the composites can form in situ microfibers and numerous high-strength shish-kebab and hybrid shish-kebab structures are formed. Additionally, the distribution of fibers and high-strength oriented structures in the composites expands to the core region with the increase in vibration times. As a result, the tensile strength, tensile modulus and surface hardness of VIM-6 can reach a high level of 66.5 MPa, 981.4 MPa and 72, respectively. Therefore, a high-performance HDPE product is successfully prepared in this study, which is of great importance for expanding the application range of HDPE products. [ABSTRACT FROM AUTHOR]

The current study aimed to investigate boron carbide and boric acid nanoparticles (NPs) as absorbents for thermal neutrons and high-density polyethylene (HDPE) as a substrate and neutron moderator for fast neutrons. The goal was to assess the performance of boron carbide and boric acid NPs based on HDPE as a nanoshield of photoneutrons from medical linear accelerators. This study was conducted in two parts of simulation and practice. The Monte Carlo (MC) simulation involved modeling and verification of the single-layer, double-layer, and combined nanoshields by selecting nanomaterials and substrates and, finally, calculating the macroscopic cross-sections. The practical part involved manufacturing nanoshields based on the simulation results and evaluating the manufactured nanocomposites via experimental measurements. MC simulation results with an uncertainty of less than 1% showed that for the monolayer samples, the best result belonged to boron carbide at a concentration of 10% and a macroscopic cross-section of 0.933 cm–1. At a concentration of 20%, the highest value among the double-layer samples was 0.936 cm–1 and for the combined samples, this value was 0.928 cm–1. Boron carbide single-layer nanocomposites at a 10% concentration, as well as the bilayer nanoshield of 10% boron carbide and 20% boric acid performed well; however, the best performance belonged to the nanoshield with a macroscopic cross-section of 0.960 and the combination containing 5% boron carbide and 10% boric acid. The research suggests that utilizing boron carbide and boric acid nanoshields in combination with HDPE holds promise as a viable approach to protecting from the photoneutrons. Further exploration of these nanocomposite shields and their practical applications is warranted, with the potential to yield significant advancements in radiation therapy safety and efficacy. [ABSTRACT FROM AUTHOR]

Transportation of acidic fluids containing hydrogen sulfide (H2S) by flexible reinforced thermoplastic pipes can cause safety problems due to diffusion of H2S in the pipe. Herein, high-density polyethylene (HDPE) composites are prepared with a large amount of zinc oxide (ZnO) particles as absorbent fillers by melt-mixing via introducing maleic anhydride-grafted polyethylene (PE-g-MAH) and maleic anhydride-grafted poly(ethylene-co-octene) (POE-g-MAH) as dual-compatibilizer. By controlling the mass ratio of the two compatibilizers, ZnO particles can be encapsulated by PE-g-MAH and POE-g-MAH so that mechanical properties of the prepared HDPE/ZnO composites are improved owing to enhanced compatibility between the filler and the resin. By adding PE-g-MAH and POE-g-MAH with total 10 wt% in a mass ratio of 1/3, the HDPE/ZnO composite containing 50 wt% ZnO exhibits 37.3 ± 3.8 MPa of yield strength, 576 ± 16 MPa of flexural modulus, and 84.4 ± 1.4 kJ m-2 of notched Izod impact strength corrected to 311 ± 24.9 kJ m-2. After exposure in H2S at 0.1 MPa for 7 days, the diffusion distance of H2S in the composite is 659 ± 17 μm, demonstrating a high barrier ability on H2S via absorption. This study provides a feasible method for preparation of polymer composites with suitable mechanical properties for inhibiting H2S permeation in reinforced thermoplastic pipes. [ABSTRACT FROM AUTHOR]

The high volume of plastic waste and the extremely low recycling rate have created a serious challenge worldwide. Local distributed recycling and additive manufacturing (DRAM) offers a solution by economically incentivizing local recycling. One DRAM technology capable of processing large quantities of plastic waste is fused granular fabrication, where solid shredded plastic waste can be reused directly as 3D printing feedstock. This study presents an experimental assessment of multi‐material recycling printability using two of the most common thermoplastics in the beverage industry, polyethylene terephthalate (PET) and high‐density polyethylene (HDPE), and the feasibility of mixing PET and HDPE to be used as a feedstock material for large‐scale 3‐D printing. After the material collection, shredding, and cleaning, the characterization and optimization of parameters for 3D printing were performed. Results showed the feasibility of printing a large object from rPET/rHDPE flakes, reducing production costs by up to 88%. Highlights: Study: multi‐material recycling printability of PET‐HDPE.Large‐scale fused particle‐based 3‐D printing technically possible.Direct waste 3‐D printing rPET/rHDPE flakes, reducing production costs up to 88%. [ABSTRACT FROM AUTHOR]

The use of Type IV cylinders for gas storage is becoming more widespread in various sectors, especially in transportation, owing to the lightweight nature of this type of cylinder, which is composed of a polymeric liner that exerts a barrier effect and an outer composite material shell that primarily imparts mechanical strength. In this work, the failure analysis of an HDPE liner in a Type IV cylinder for high-pressure storage was carried out. The breakdown occurred during a cyclic pressure test at room temperature and manifested in the hemispherical head area, as cracks perpendicular to the liner pinch-off line. The failed sample was thoroughly investigated and its characteristics were compared with those of other liners at different stages of production of a Type IV cylinder (blow molding, curing of the composite material). An examination of the liner showed that no significant chemical and morphological changes occurred during the production cycle of a Type IV cylinder that could justify the liner rupture, and that the most likely cause of failure was a design-related fatigue phenomenon. [ABSTRACT FROM AUTHOR]

In the present research work, calcium pimelate (CaPim) was synthesized and investigated as an additive for high-density polyethylene (HDPE). HDPE/CaPim nanocomposites were prepared by melt-mixing, with CaPim content ranging from 0.1% to 1%, affording white homogeneous materials. The chemical structure of the nanocomposites and the incorporation of CaPim was confirmed by infrared spectroscopy. The surficial morphology and the additive distribution were examined by scanning electron microscopy. Differential scanning calorimetry and X-ray diffraction measurements showed that the thermal transitions and crystal structure of HDPE are not affected by the incorporation of CaPim, while the mechanical properties are retained overall. This study focuses on the thermal degradation of HDPE nanocomposites, investigating the degradation mechanism and kinetic parameters through various analytical methods. Isoconversional techniques, including the Friedman method, Vyazovkin analysis, and Ozawa Flynn Wall analysis, were employed to calculate activation energies (Eα). The degradation mechanism and kinetic triplet were determined based on a multivariate non-linear regression method (model-fitting). Finally, the presence of a CaPim additive was shown to increase the Eα of thermal degradation, consistent with the calculated dependence of Eα on the degree of conversion and the improved thermal stability of the HDPE matrix. [ABSTRACT FROM AUTHOR]

Elastomeric polymers such as high‐density polyethylene, have a variety of desirable features, that have supplanted traditional materials. However, high‐density polyethylene (HDPE) shows inadequate wear resistance, which limits its use for industrial applications, particularly in low‐load‐bearing applications such as flexible energy harvesting devices and sensors. The current work is engrossed in investigating the influence of hybrid reinforcements CaCO3 particles and bentonite nano clay as secondary reinforcements in high‐density polyethylene (HDPE)‐based composites on the wear and friction properties. The reinforcements were melt compounded with HDPE using a Brabender mixer and sampled using an injection molding machine. The wear test (ASTM G‐99‐04) was performed by a pin‐on‐disk tribo‐tester. In comparison to a base matrix, the synthesized hybrid composite achieved the maximum improvement in wear rate of 93%. The results revealed that there is a significant improvement in wear resistance. Morphological analysis revealed that due to the encapsulation and compatibilization effect of bentonite nano clay the hybrid composite exhibited improved wear performance. The results signify the synergistic effect of filler particles resulted in sufficient bonding for stress transfer due to the encapsulation of CaCO3 by nano clay. The wear mechanism observed optically was abrasion, fatigue, and adhesion wear that changed with the change in the weight percent of nanoparticles. Finally, the prepared composite with enhanced tribological properties such as low wear rate, low friction coefficient, and enhanced morphology can be used in low load‐bearing wear applications such as turbo nanogenerators and piezo nanogenerators. Highlights: Bentonite nano clay and CaCO3 dispersed homogeneously in HDPE matrix.Wear resistance of HDPE increases by reinforcing particles (nano‐clay and CaCO3).Micro‐cutting, deformations, and particle husks were the possible wear mechanism.Encapsulation effects the hybrid composite to exhibit improved wear performance. [ABSTRACT FROM AUTHOR]

• PFAS sorb to and can diffuse through HDPE geomembranes. • Partition coefficients range from 3.8 to 98.3 L/kg. • The functional group and structure of PFAS affect partition and diffusion. • Diffusion coefficients vary from the order of 10-18 m2/s to 10-17 m2/s. • Estimated breakthrough times are more than 1500 years for intact 1.5 mm HDPE GM. The objective of this study is to investigate the fate and transport of per-polyfluoroalkyl substances (PFAS) through a high-density polyethylene (HDPE) geomembrane (GM) that is commonly used in landfill composite liner systems. Tests were conducted to measure the sorption and diffusion of per-polyfluoroalkyl substances (PFAS) with varying number of carbons in chain and functional groups on HDPE GM. Perfluoroalkyl carboxyl acids (PFCAs), perfluoroalkyl sulphonic acids (PFSAs), alkyl-sulfonamidoacetic acids (FOSAAs), fluorotelomer sulfonic acids (FtSAs), alkane sulfonamides (FOSA) and ether carboxylic acids (Gen X) were investigated in this study. The partition coefficients (K d) on HDPE GM ranged from 3.8 to 98.3 L/kg. PFAS with amide and sulfonic functional groups showed stronger sorption than that of PFAS with carboxylic acid functional groups. Molecular weight directly affected the K d for long-chained PFAS whereas the K d of short-chained PFAS was not sensitive to molecular weight. The diffusion coefficients (D g) of PFCAs and PFSAs through 0.1-mm HDPE GM were found to be in the orders of 10-18 to 10-17 m2/s. The D g decreased with increasing molar mass and were also observed to be dependent on the functional group. D g of PFSAs was lower than that of PFCAs for similar number of carbons in the chain. The estimated mass flux for PFAS in an intact 1.5-mm HDPE GM varied from 38.7 to 2080.8 ng/m2/year whereas the estimated diffusive breakthrough time for PFAS in intact 1.5-mm HDPE was 1526 years or longer. [ABSTRACT FROM AUTHOR]

Demand for natural fibers has increased in recent years due to the requirement for biodegradable materials. Owing to the increasing awareness on the overuse and over-dumping of plastics in the environment, the current work focused on a solution by using tree leaves as a particulate reinforcement which is one of the common waste products of trees. In this regard, Norfolk pine (NOP) tree leaf particulates filled High-Density Polyethylene (HDPE) composites were fabricated through injection moulding technique with different filler weight % of 0, 10, 20, 30, 40, and 50 wt. %. The study of the crystalline structure of the fillers and the detection of functional compounds in the materials were carried out through X-ray diffraction (XRD) and Energy dispersive X-ray spectroscopic (EDX) analysis. Tensile strength, compressive strength, and flexural strength of the fabricated composite specimens were also assessed. Results revealed that the mechanical properties of the 30 wt. % pine tree leaf-filled HDPE composites were found to be superior when compared to pure HDPE composites. The failure surface morphology of the composite samples was examined using scanning electron microscopy (SEM). The melting point and decomposition of 30 wt. % NOP leaf particulate-filled HDPE composites specimen, whose mechanical properties were higher, were examined using thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). From the results, it was found that NOP fillers can be used as an effective reinforcement in polymer composites. [ABSTRACT FROM AUTHOR]

Natural fiber‐reinforced composites are showing promising results compared to synthetic fiber‐reinforced composites. Therefore, the present work highlights the utilization of chemically treated bamboo‐fiber (BF) for the preparation of bamboo‐fiber high‐density polyethylene composites (BF/HDPE). Both virgin HDPE and recycled HDPE (r‐HDPE) are considered for the preparation of bamboo fiber (BF) composite and their physico‐mechanical properties are evaluated. On alkali and stearic acid treatment, more fibrillation and surface roughness are observed in the BF surface which created more contacting surfaces to improve the interfacial interaction between the BF and HDPE & r‐HDPE matrix. The tensile strength of stearic acid‐treated BF/HDPE is increased by 9.26% and stearic acid‐treated BF‐ rHDPE shows an increment of 16.5%. Similar observations are made for impact strength which confirms the improved dispersion of BF in both matrices. The improved interfacial bonding between BFs and HDPE matrix and good dispersion between fibers and matrix can further be confirmed through the SEM images of composite fractured surfaces and FTIR analysis. Highlights: Surface of BF has been modified by NaOH and stearic acid treatment.Modified fibers are used as reinforcement in virgin and r‐HDPE composites.Stearic acid treatment enhances the tensile strength of composites.Surface modification has significant impact on r‐HDPE composites. [ABSTRACT FROM AUTHOR]

In this study, the thermal degradation behavior of both poly(3,3,4,4,5,5,6,6,7,7,8,8,8-dodecafluoro-5-methyloctyl-4-(acryloyloxy) benzoate), poly(ABCF13) and its graft copolymers onto high-density polyethylene (HDPE) was investigated in detail. The homopolymers and grafted copolymers were synthesized using the bulk-melt polymerization method in the presence of benzoyl peroxide; 10% and 40% of ABCF13 were used in the graft copolymers. The combined analytical technique, Thermo Gravimetric Analysis coupled with Fourier Transform Infrared Spectroscopy (TGA/FTIR), was utilized to understand the obtained products' thermal behavior and formed decomposition chemicals. The thermal tests were carried out in both air and N2 atmospheres. The experimental results showed that the first weight loss of poly(ABCF13) in air and N2 atmospheres started at about 226 C (1.00%), and the primary and early decomposition product was determined as CO2. The weight loss pattern in graft copolymers at lower concentrations closely resembled that of the homopolymer. However, at higher concentrations, the resulting products exhibited a distinct decomposition mechanism characterized by a gradual decrease in trend. This segmented behavior may indicate the coexistence of the homopolymer and grafted copolymers within the matrix. Moreover, the findings showed that the semi-fluorinated grafted unit had a substantial retardation effect on the polymer. [ABSTRACT FROM AUTHOR]

This article analyzes the aging effect of HDPE sewer pipes when exposed to sulfuric acid at different temperatures. The mechanical properties, structural and morphological changes were evaluated. Results showed an impressive environmental degradation of HDPE. The tensile test showed that with a well-correlated increase in immersion time and higher temperatures, the elongation and ultimate stress of HDPE decreased. At 60 °C, the elongation at break indicated, at every time interval, an abrupt drop and a simultaneous loss of ductility. The micro-structural FTIR absorptions at 719-730, 1462-1472, 2848, 2916 and 3400 cm-1 were detected and compared using the spectrum of an unaged HDPE. The modification of the mechanical properties seems to correlate well with the structural observations obtained from the scanning electron micrographs. Eventually, it was discovered, via thermal aging studies, that the combination of temperature and sulfuric acid appears to be a major factor in high-density polyethylene breakdown. [ABSTRACT FROM AUTHOR]

High‐density polyethylene (HDPE) polymer is one of the largest contributors to plastic wastes causing detrimental effects on various sectors of society, and is not biodegradable in nature. In the first stage, river sand and a recycled HDPE as a binder were used to manufacture eco‐friendly plastic sand bricks with various sand(s):plastic(p) ratios: 60s:40p; 65s:35p; 70s:30p; 75s:25p; 80s:20p; 85s:15p. In the second stage, 1%, 5%, and 10% of Kaolin Clay was added to each ratio of sand:plastic, respectively. Three mechanical tests were conducted: compressive strength, impact, and short beam strength. First, the addition of 5% Kaolin Clay to 75s:25p ratio increased compressive strength significantly from 21.4 to 52.76 MPa. Second, the addition of 10% Kaolin Clay in the ratio of 75s:25p mixture increased the impact strength from 4.8 to 5 J. Finally, the addition of 5% Kaolin Clay in the ratio of 60s:40p mixture increased the short beam strength significantly from 1.84 to 2.27 MPa. SEM analysis showed a well‐compacted interface indicating effective bonding between the HDPE and river sand particles in the 75s:25p ratio. Hence, the results of this study present a potential for the use of recycled HDPE plastic to manufacture plastic sand bricks. Highlights: Addition of Kaolin Clay improved the mechanical properties of the composite material. [ABSTRACT FROM AUTHOR]

Microbeads used in personal care products (PCPs) as an exfoliating agent or as a sorbent phase for delivering active ingredients are the most common sources of microplastics. The release of these plastic microbeads into aquatic environments has raised significant concerns due to their direct availability for ingestion by organisms upon entering the recipient waters. In this study, twelve personal care products (PCPs; 5 face washes and 7 scrubs) were analyzed for microbead content, size, polymer type, and buoyant behavior. Among the face washes, the highest microbead content (i.e., 11 ± 1.2 mg/g) was found in Neutrogena (NS), while the lowest was found in Nivea (NI) with 0.33 ± 0 mg/g. In case of scrubs, Cool and Cool (CL) contained a higher concentration of microbeads (i.e., 57.08±14.15 mg/g) and a lower concentration was found in Yong Chin (YC) (i.e., 10.5±1.5 mg/g). The sizes of microbeads ranged from 3.14 ± 0 to 747 ± 313 μm, and most of the isolated microbeads showed negative buoyant behavior in both freshwater and seawater. The FTIR spectra showed that the microbeads were mainly composed of ethyl-vinyl acetate (66.66%), high-density polyethylene (16.66%), polyethylene terephthalate (8.3%), and nitrile (8.3%). The presence of plastic microbeads in PCPs highlights the need to regulate their use as an exfoliating agent and to raise public awareness to prevent the discharge of these persistent and potentially harmful elements into the environment. [ABSTRACT FROM AUTHOR]

The in-series connections of multi-pipes involving steel and polymeric materials were identified as being an effective design tool to extenuate water-hammer surges induced into an existing steel-main pipe-based hydraulic system. Although this design measure significantly reduced the magnitude of pressure-wave surges, it was limited by the expansion of the period of pressure-wave oscillations. This study addressed a holistical exploration and comparison of the effectiveness of the in-series connections of multi-pipes design measure used to control water-hammer surges into an existing steel water distribution piping systems. The extended one-dimensional water-hammer model, including the Vitkovsky and Kelvin-Voigt formulations, was developed to describe the transient flow, together with the Method of Characteristics implemented for numerical computations. The comparison of the numerical solution with observed data, quoted in the literature, and the alternative numerical solution demonstrated the accuracy of the developed solver. The test case appraised the capability of a variety of in-series setups of steel and plastic main-pipes for a reservoir-pipe-valve – based hydraulic system. The high- and low-density polyethylene (HDPE and LDPE) plastic material types were considered in this investigation. Results showed that the hydraulic system setup built upon an (LDPE-steel-LDPE) provided a satisfactory tradeoff between the dampening of pressure-wave magnitude and the expansion of the period of pressure-wave oscillations [ABSTRACT FROM AUTHOR]

The presented paper introduces an approach for fatigue lifetime predictions of notched round bar specimens made of HDPE. This approach uses axial stress distribution calculated from finite element analysis and experimental fatigue data. The fatigue results obtained experimentally on the round bar specimens with "v" notch with radius R = 0.4 mm and extremely sharp notch are used for a determination of averaging distance. The averaging distance is applied to specimen with different notch radius for determination of its fatigue lifetime. The fatigue lifetime prediction of a specimen with notch radius R = 0.1 mm is performed. These fatigue lifetime predictions are compared to experimental fatigue data. [ABSTRACT FROM AUTHOR]

Featured Application: This work is of particular interest in the design of products widely used in daily life, such as HDPE and LLDPE blend plastic bags. The aim of this study is to analyze how the main process parameters (BUR, TUR, and TR) affect the mechanical properties of this type of product, helping designers to adapt the production to customers' new requirements while maintaining the product properties. All the samples were manufactured on an industrial scale. The results are beneficial so that the highest tensile and impact properties can be obtained through minimal changes in the already mentioned process parameters, thus also reducing the amount of waste due to products manufactured outside the specification limits. Polyethylene plastic bags manufactured via blown film extrusion have different quality specifications depending on their intended use. It is known that the mechanical properties of a film depend on the process parameters established, but little is known concerning how they affect one another, even more so due to the variety of polyethylene materials and processing techniques. This study focuses on establishing a proper correspondence of important mechanical properties like the dart impact, tensile strength at break, and elongation at break with commonly used process parameters like the blow-up ratio, take-up ratio, thickness reduction, and neck height, for a high-density polyethylene hexene copolymer and a linear low-density polyethylene butene copolymer blend film. Because this polyethylene mixture is an anisotropic material, interesting R2 values equal to or higher than 0.90 were found: a BUR with elongation at break and tensile strength at break in the MD and TD, a TUR with elongation at break in the MD and tensile strength at break in the MD and TD, and a TR with elongation at break and tensile strength at break in the MD. Also, a relationship between the dart impact and both the neck height and thickness were found. [ABSTRACT FROM AUTHOR]

[Display omitted] • Exploitation of the impact delamination phenomenon. • Novel mechanical method to separate HDPE from laminates for recycling. • Fine tuning of shredding operation to separate HPDE while cutting. • Reduced amounts of solvent wastes and improved environmental friendliness. • Very rapid HDPE separation, reduced unit operations and plant footprint. High-density polythene (HDPE) is difficult to separate from food packaging waste for recycling because the packaging occasionally has multilayer plastic labels attached. Solvents are employed in the current separation techniques to remove undesirable layers from HDPE substrates. The possibility of separating HDPE via the impact-delamination phenomenon was explored both theoretically and experimentally. Using the cohesive zone model (CZM), the decohesion of layers in a model two-layer laminate made of HDPE and LDPE layers was studied theoretically. According to this study, stress waves emerge and severely damage the adhesion between the layers as a cutting blade strikes the laminate at speeds greater than 40 m/s. The damage can be enhanced by increasing the strike velocity and the apex radius of the blade. These findings show that a novel plastic delaminator that can cut and delaminate the laminates simultaneously can be designed. The proposed machine will feature two sets of blades with varying edge apex radii. One set of blades can be designed to cause the most adhesion damage while the other blades cut the laminate. This unique combination of cutting and delamination operations has several benefits, including less solvent waste and downstream processes, greater environmental friendliness, and faster HDPE separation. Laminates from HDPE milk bottles were cut using a high-speed cutter-blender with six blades to test the predicted results. The cut HDPE flakes were separated pneumatically. According to FTIR analysis and SEM, only a trace of adhesive was present on the cut and separated HDPE flakes. [ABSTRACT FROM AUTHOR]

In this paper, a new bio‐based flame retardant MHPA was prepared by the reaction of magnesium hydroxide (MH) and phytic acid (PA). Then the crosslinked high‐density polyethylene (HDPE) flame‐retardant composite was prepared by adding it and silicone rubber (SR) into HDPE and using electron beam irradiation. The test results of limiting oxygen index (LOI) and cone calorimeter test (CCT) show that the combination of MHPA and SR can increase the flame retardancy and smoke suppression performance of HDPE. The LOI of HDPE composite with 10 parts of SR is 28.3%, and its pHRR, THR and TSP values are reduced to 454.1 kW/m2, 99.7 MJ/m2 and 8.3 m2, respectively, which is because MHPA and SR jointly promote the formation of continuous and high‐density carbon slag in the combustion process of HDPE and inhibit the penetration of flame. In addition, the HDPE composite with 10 parts of SR has significant tensile strength, elongation breaking strength and tear strength, because SR can produce continuous stable structure with HDPE after irradiation and crosslinking. Therefore, this study verified that MHPA and SR together can effectively improve the flame retardancy, smoke suppression and mechanical properties of HDPE composite. [ABSTRACT FROM AUTHOR]

Modification with nanoparticles is an effective way of overcoming the inherent defects of high‐density polyethylene (HDPE). However, the uniform dispersion of nanoparticles in the polymer matrix is the key point of this method. Here, natural rubber latex (NRL) was used for the auxiliary dispersion of self‐made nano zinc oxide (nano‐ZnO) to realize the uniform dispersion of nano‐ZnO in HDPE. The HDPE‐based nanocomposite with excellent thermo‐oxidative aging resistance, mechanical properties and electrical insulation properties were successfully prepared. Three weight percent of nano‐ZnO was uniformly dispersed in HDPE (HLZ3), which not only synergistically toughened HDPE with natural rubber (coagulated natural rubber latex, NR), but also maintained the tensile strength of the matrix. Moreover, the interfacial interactions between nanoparticles and polymers improved the alternating current (AC) breakdown strength and volume resistivity of the HDPE matrix. After aging treatment, the crystallinity of HLZ3 decreased very little, and its carbonyl index was much smaller than that of pure HDPE. Therefore, it has the best performance retention rate. This nanoparticle dispersion method has certain reference significance. And this HDPE‐based nanocomposite material is expected to be used in the outer sheath of cables. [ABSTRACT FROM AUTHOR]

The durability of five 1.5-mm thick geomembranes (GMBs) is investigated in pH 0.5 and 13.5 synthetic mining solutions using immersion tests. Two high density polyethylene (HDPE), two linear low density polyethylene (LLDPE), and one blended polyethylene (BPO) GMBs are investigated at 85 °C for incubation durations of 4.5–6.5 years. It is shown that the degradation of all five GMBs in the high pH solution is faster than in the low pH solution. In the pH 0.5 solution, one of the HDPEs and the BPO GMBs exhibited polymer degradation before or at the time of the depletion of their antioxidants. In pH 13.5, four out of the five GMBs exhibited degradation and followed the conceptual three-stage degradation model until nominal failure. However, there is no correlation between the long-term performance of these GMBs and their resin type or their initial properties since one of the examined LLDPEs outperformed all the higher density/crystallinity GMBs with higher initial properties while the other LLDPE did not perform well. Thus, when selecting a GMB for a desired application, the relative performance of different candidate GMBs can be only assessed using immersion tests using the solutions expected in the field. • First comparison of the degradation behaviour of HDPE, LLDPE, and BPO geomembranes incubated for up to 6.5 years at 85 °C. • Estimates the time to nominal failure in pH 0.5 and pH 13.5 synthetic mining solutions. • Examines the role of the stabilizers and the resin type on the longevity of five different geomembranes. • Compares the morphology of the failure surfaces after stress cracking from HDPE, LLDPE, and BPO geomembranes. [ABSTRACT FROM AUTHOR]

This article analyzes the aging effect of HDPE sewer pipes when exposed to sulfuric acid at different temperatures. The mechanical properties, structural and morphological changes were evaluated. Results showed an impressive environmental degradation of HDPE. The tensile test showed that with a well-correlated increase in immersion time and higher temperatures, the elongation and ultimate stress of HDPE decreased. At 60 °C, the elongation at break indicated, at every time interval, an abrupt drop and a simultaneous loss of ductility. The micro-structural FTIR absorptions at 719-730, 1462-1472, 2848, 2916 and 3400 cm-1 were detected and compared using the spectrum of an unaged HDPE. The modification of the mechanical properties seems to correlate well with the structural observations obtained from the scanning electron micrographs. Eventually, it was discovered, via thermal aging studies, that the combination of temperature and sulfuric acid appears to be a major factor in high-density polyethylene breakdown. [ABSTRACT FROM AUTHOR]

Due to chlorine's ability to kill bacteria and fungi through a chemical reaction, chlorine solutions are commonly used to clean and disinfect numerous public facilities, although these actions are also dependent to the equipment present in those facilities. Accordingly, the interest in studying its effect when in contact with different materials is obvious. This study was carried out through accelerated degradation tests and various analysis methods (optical microscope, scanning electron microscope, and tensile tests). The objective was to observe the wear presented by three polymeric materials, polyvinyl chloride (PVC), high-density polyethylene (HDPE), and polypropylene (PP), when exposed to chlorine's action in swimming pools and drinking water treatment plants. The resulting effect depends on the chlorine content and the type of contact between the chemical agent and the material. The aim was to select the material less likely to be affected by chlorine through tests and analyses, allowing a longer component life. The use of certain more resistant polymeric materials can drastically reduce maintenance, reducing fundamental factors such as costs, the downtime of municipal facilities, and also the risk to public health. It was concluded that PVC has the most stable behaviour overall when in contact with chlorine solutions. [ABSTRACT FROM AUTHOR]

Wood-polymer composites (WPCs) combine the properties of wood and polymers. Creating composites involves adding plant or wood fibers as fillers to a polymer matrix. This study used mahogany and mango wood sawdust as reinforcement materials, while high-density polyethylene (HDPE) and polyvinyl chloride (PVC) were used as matrices. The investigated data in this study comprises four different (10, 20, 30, and 40) weight percentages (wt%) of mahogany and mango sawdust paired with corresponding wt% (90, 80, 70, and60) of HDPE and PVC matrices. The extrusion method produced composites with different amounts of sawdust and polymer matrices. Wood polymer composites were characterized by examining their mechanical properties, and scanning electron microscopy (SEM) was employed to analyze their morphology. The results showed that the maximum tensile strength was obtained from the 20% for both sawdust composites. The ultimate tensile strength was recorded at 15.28 MPa for Mahogany sawdust-HDPE (Mh-HDPE) composite, whereas the Mahogany sawdust-PVC (Mh-PVC) exhibited the lowest tensile strength at 2.38 MPa. In addition, HDPE-based composite shows higher tensile strength (11.56 MPa) with Mango sawdust than PVC-based composites (2.28 MPa). Tensile strength, and impact strength of the fabricated composites were also assessed by ASTM standards. The maximum impact strength was obtained at 10wt% of sawdust for all four composites investigated in this study. It was also observed that impact strength significantly decreased with the increase of fiber percentage in the composite. These results demonstrated the highest mechanical properties of the Mh-HDPE than the other composites, which SEM further investigated. The morphological analyses confirmed uniform mixing of sawdust and polymer matrices, evident by the absence of no pores, cavities, or voids in the prepared composites. [ABSTRACT FROM AUTHOR]

High-density polyethylene (HDPE) geomembranes (GMs) are frequently used as fluid barrier components of cover systems for mine site reclamation in regions that are prone to freeze–thaw cycles (FTCs). However, HDPE GMs are more susceptible to stress cracking than linear low-density polyethylene (LLDPE) GMs. Hence, LLDPE GMs are increasingly considered as alternatives to HDPE GMs in cover systems. Nevertheless, little information is available on LLDPE compared to HDPE GMs. Moreover, little is known about the changes in the fluid barrier properties (the equivalent hydraulic conductivity and the oxygen sorption and diffusion coefficients) for these two materials with FTCs. The purpose of this study is therefore to compare the effects of FTCs on the tensile, hydraulic, and oxygen sorption and diffusion properties of HDPE and LLDPE GMs. To do so, GM sheets were subjected up to 300 FTCs. Mechanically, both GMs got stiffer and their tensile break properties increased with increasing number of FTCs. However, although the GM fluid barrier properties changed with FTCs, the equivalent hydraulic conductivity and the oxygen permeation coefficient remained within an order of magnitude of 10−14 m/s and 10−13 m2/s, respectively. Up to 300 FTCs would therefore have no adverse effects on HDPE and LLDPE GMs. [ABSTRACT FROM AUTHOR]

The polyethylene-based matrix composites were facilitated in various engineering applications for good mechanical stability, dynamic load stability, and superior wear resistance. High-density polyethylene (HDPE) composites are gathering significance in agricultural and biomedical machinery applications. Due to stress cracking during high tensile load, it was limited. This investigation is an attempt to increase the tensile, flexural, and impact strength and wear behaviour of HDPE composites with inclusions of 0, 5, 10, and 15 vol% aluminas (Al2O3f) and constant 5 vol% of titanium oxide (TiO2f) bio-ceramic fillers through magnetic wave assisted injection mould technique. The influences of ceramic filler on HDPE composite's tensile, flexural, and impact strength were studied by ASTM D638, D790, and D256, respectively. ASTM G99 standard is used for estimating the wear resistance of composite by 10, 15, 20, 25 and 30N average load at 0.75 m/sec sliding velocity. The investigation outcome result of sample 4 offering high tensile, impact, and flexural strength 17.29 ± 1.98 MPa, 16.01 ± 0.13 kJ/m2, and 41.61 ± 1.56 MPa, respectively. The higher wear resistance with a low wear rate of (less than) 10 µm was found in sample 4. [ABSTRACT FROM AUTHOR]

A relatively new technique, friction stir welding (FSW), that works on the solid-state joining principle has shown significant development in recent years. This technique is based on the generation of thermal energy necessary to form the joint through the friction and material deformation caused by a non-consumable tool plunging into the workpiece. The FSW has previously been used for welding metallic materials such as aluminum and its alloys that were difficult to join using conventional methods. However, instead of the use of heavier metals in the automotive, aviation, and many other engineering industries, the preference for lightweight materials such as polymer materials due to their specific strength, corrosion resistance, high degree of processing, and design freedom as well as their lightness, has resulted in the emergence of the need for new techniques for joining these materials. The FSW technique has attracted great attention because of less material waste, less energy requirement, less distortion, and residual stresses. It is an environmentally friendly and economical method, unlike fusion welding techniques. Although significant progress has been made in this method, which has great potential in polymer welding applications, difficulties remain in welding high-density polyethylene (HDPE) with the FSW, which has a growing demand in many industrial applications. In addition, the limited number, as well as shallow of compiled studies on this subject in the literature, encouraged us to carry out this study. This review summarizes the results from previous studies focusing on the weldability of HDPE materials using the FSW technique. Furthermore, in this article, the operation of the process, its history, advantages, and limitations compared to other methods, materials that have hitherto been welded with it, its critical parameters that affect the mechanical properties of the welded joint, and the methods used for the characterization of the structure after the process, are reviewed. Finally, it is aimed to better understand the joining process and to shed light for researchers in future works on welding HDPE material with the FSW. [ABSTRACT FROM AUTHOR]

This study aims to determine the mechanical and thermal properties of high density polyethylene (HDPE) thermoplastic nanocomposite with oil palm boiler ash (OPBA) filler made by coprecipitation method and synthesized with PEG 6000 surfactant with OPBA-PEG 6000 filler variations. The filler composition used was HDPE/OPBA (100/0, 98/2, 96/4, 94/6, 92/8, 90/10) wt%. Nanocomposites were prepared using a Rheomixer HAAKE Polylab OS System at 150°C and 60 rpm for 10 minutes. Mechanical properties of HDPE with increased OPBA filler content is beyond a certain threshold, the tensile strength of the HDPE composite may start to decrease. This decrease can be attributed to several factors. Firstly, as the filler content increases, the HDPE matrix may become less effective in transferring stress, resulting in reduced load-bearing capacity. This is confirmed from the SEM results that the filler agglomerates and cracks occur in the composite. The composite material may exhibit a lower Young's modulus compared to pure HDPE with low Young's modulus tend to have high elongation at break which indicatie a flexible and ductile composite. The melting point of peaks 1 and 2 on 0% filler and other fillers did not change significantly even at certain compositions the melting point decreased after adding filler. [ABSTRACT FROM AUTHOR]

The rise in the utilization of radiation across various domains necessitates the advancement of next-generation radiation shielding materials that are devoid of lead. Due to their low weight and flexibility, polymer composites are considered as environmentally friendly alternative materials that can be used instead of toxic and high-weight lead for radiation shielding. From this point of view, the present study has focused on examining the radiation shielding performance of tantalum pentoxide doped high-density polyethylene (HDPE/Ta2O5) composites (including 5, 10, and 20 wt% Ta2O5) by using WinXCom software and MCNP6 simulation. The photon energies selected corresponded to the photons emitted from the Ba-133 (81 and 356 keV), Cs-137 (662 keV), and Co-60 (1173 and 1332 keV) radioactive sources that cover X-rays along with the low-and mid-energetic gamma-rays. The mass attenuation coefficient (μ/ρ) of the composites has been calculated within the 81 keV-1332 keV photon range by utilizing WinXCom software and MCNP6 code. The other shielding parameters such as Half Value Layer (HVL), effective atomic number (Zeff), and effective electron density (Neff) have been determined. In the light of data, it has been revealed that gradual increase in Ta2O5 doping while improving the μ/ρ coefficients, Zeff, and Neff parameters, decreasing the HVL length of HDPE considerably. Additionally, the parameters obtained by WinXCom and MCNP6 simulation are in good agreement. the. Ultimately, the best ionizing shielding performance among the composites has been determined for HDPE/20% Ta2O5 composite against 81 keV photons. [ABSTRACT FROM AUTHOR]