Properties Of High Density Polyethylene Research Articles

Experimental and numerical study on HDPE/SWCNT nanocomposite elastic properties considering the processing techniques effect

The aim of this study is to evaluate the elastic properties of high-density polyethylene (HDPE) using single-walled carbon nanotubes (SWCNTs) reinforcements with experimental and Finite element method (FEM) considering two different processing techniques effect. SWCNT nanoparticles were used to strengthen the HDPE matrix at the weight fractions (wt%) of 0, 0.2, 0.4, 0.6, 0.8, and 1 and the resulting nanocomposites were processed using injection and compression moulding. From each processing method, the HDPE/SWCNTs nanocomposites tensile test specimen were prepared and tested for the elastic properties. Experimental results showed that the addition of SWCNT nanoparticles for each weight fractions and both processing methods enhanced the elastic properties of HDPE. Finally, the numerical simulations were conducted using FEM for the prediction of the elastic modulus of HDPE/SWCNT nanocomposites for both processing methods. Whereby the representative volume element (RVE) model was presented with an interfacial phase region separating the load transfer between the SWCNT and HDPE with the properties obtained from the atomic modelling results. The numerical FEM elastic modulus results were found to correlate with the experimental results.

English

English

Size-controlled, single-crystal CuO nanosheets and the resulting polyethylene–carbon nanotube nanocomposite as antimicrobial materials

In this study, size-controlled single-crystal copper oxide nanosheets (CuO NSs) were fabricated by a microwave-assisted chemical method. Next, their nanocomposites with high-density polyethylene (HDPE) were fabricated. These nanocomposites were further reinforced with carbon nanotubes (CNTs) of oil fly ash. The produced CuO NSs along with their polymer nanocomposites were evaluated as antimicrobial agents against Escherichia coli, Bacillus subtilis, and yeast Saccharomyces cerevisiae. Significant microbial-growth inhibition was observed. This inhibition correlated with oxygen defects, free Cu2+ ion release, and a change in the lattice constant c. These factors were found to increase with the increased molar ratio of the precursors and might be responsible for formation of additional reactive oxygen species. Moreover, adding 1 wt% of CuO NSs and 0.5 wt% of CNTs enhanced the mechanical properties of HDPE by ~ 20%. These results indicate that it is possible to design polymer nanocomposites that have both antimicrobial and enhanced mechanical properties for various applications, mainly in the healthcare sector.

Hydrogen diffusion through polymer membranes

This experimental study determines H2 transfer properties of High Density PolyEthylene (HDPE) or epoxy membranes. Two different techniques are compared. The pressure gradient technique is analyzed for permeability or diffusion. Results show that the main phenomenon involved is diffusion. The second technique involves a gas concentration gradient. Although implying significantly slower kinetics, this classical technique is consistent with results obtained with the faster pressure gradient technique.

Controlling the Shape of Molecular Weight Distributions in Coordination Polymerization and Its Impact on Physical Properties

High-density polyethylene (HDPE) is utilized in a multitude of commercial products worldwide due to its broad spectrum of physical properties and low production costs. Molecular weight and dispersity (Đ) are known to affect the tensile and rheological properties of HDPE, but little is known about the influence of the molecular weight distribution (MWD) shape on these properties. In this work, we investigate this matter through the temporal regulation of initiation in a living coordination-insertion polymerization of ethylene. This method provides precise control over the MWD shape which, in turn, offers a systematic study on the influence of MWD shape on the physical properties of HDPE. Through rheological testing, we observe a difference in complex viscosity and shear thinning with opposite MWD skew. However, tensile testing reveals that the MWD skew does not impact the strain at break, signifying the ability to influence HDPE processing without compromising material strength.

Comparative study of carbon-based nanofillers for improving the properties of HDPE for potential applications in food tray packaging

High-density polyethylene (HDPE)/carbon filler composites for potential applications in food tray packaging were prepared by melt compounding HDPE with one-dimensional (1D)-multiwalled carbon nanotubes (MWCNT), two-dimensional (2D)-graphene oxide (GO) and three-dimensional (3D)-carbon black (CB) on a twin-screw extruder. The morphology of fillers inside the HDPE matrix was characterized and correlated to the mechanical, thermal and barrier properties of the nanocomposites. The results showed the distinct effect of CB on the mechanical, thermal and barrier properties of HDPE from MWCNT and GO. The morphological analysis revealed uniform dispersion for all the fillers, but the agglomerate formation was a lot more evident in MWCNT-based nanocomposites. Ball milling solved the large agglomerate formation for MWCNT and produced nanocomposites with improved mechanical properties. In comparison to 1D and 2D nanofillers, the 3D-CB filler showed remarkable contribution to tensile toughness but caused a reduction in barrier properties of HDPE, the increase in tensile toughness was attributed to uniform dispersion of the filler, enhanced mechanical interlocking between filler and polymer, appearance of high degree of crazing on tested samples and increase in nanocomposite internal temperature during tensile testing.

Mechanical, water uptake properties, and biodegradability of polystyrene‐coated sisal fiber‐reinforced high‐density polyethylene

AbstractIn this study, composites of high‐density polyethylene (HDPE) with uncoated sisal fibers (UF) and that coated (CF) with polystyrene (PS) and vinyltrimethoxysilane (VTMS) copolymers (PSV) were fabricated. The prepared copolymers containing 2.5% VTMS (PSa) and 5% VTMS (PSb) were used to coat the sisal fiber with a thin layer of hydrophobic polymer to make coated fibers CFa and CFb, respectively. The coating process was verified by Fourier‐transform infrared spectroscopy (FTIR) analysis. The mechanical, water absorption, morphology, and biodegradation properties of HDPE and its composites with UF (HUF) and CF (HCF) composites were evaluated. The tensile strength and flexural strength were improved by 19.5% and 34% after addition of 5% CFb to HDPE compared to HDPE composite which contains 5% UF. The results manifested significant reduction in the amount of water absorbed by CF and HCF composites compared to UF and HUF composites. Additionally, scanning electron micrographs indicated that the coating of sisal fibers with PSV improved the compatibility between sisal fibers and HDPE polymeric matrix. Also, the composites containing CF exhibited a lower rate of degradation than those containing UF.

Compatibility study of high-density polyethylene with ethanol–gasoline and biodiesel

To further evaluate the compatibility of high-density polyethylene (HDPE) with the biofuels included ethanol–gasoline E30 and biodiesel B30, especially the change of mechanical properties of HDPE over soaking time, soaking tests were performed in E30 and B30 fuels at 45°C for 1608 h. Volume/mass change, yield stress, yield elongation, and impact strength of HDPE were measured at different soaking times. In all fuel soaking tests, more fuel absorption occurred between HDPE and fuels than oxidative damage. Due to higher polarity of bioethanol, E30 is less easily absorbed by HDPE than gasoline and causes less volume and mass change of HDPE. Compared with gasoline and E30, diesel and B30 were less likely to be absorbed by HDPE and there was no significant different of HDPE volume and mass change soaked in them. As fuel could be more easily stored in the amorphous phase of the HDPE than in the crystalline phase, the significant increase of yield elongation and little change of yield stress and the absorbed fuel may act as a plasticizer in HDPE. The increase of impact strength was due to the HDPE became more ductile after fuel soaking rather than strength increase. The compatibility research between HDPE and biofuel can help design engineers to evaluate the performance changes of plastic fuel tank products made of HDPE after long-term fuel soaking.

Effective reinforcements for thermoplastics based on carbon nanotubes of oil fly ash

Carbon nanotubes (CNTs) are widely investigated for preparing polymer nanocomposites, owing to their unique mechanical properties. However, dispersing CNTs uniformly in a polymer matrix and controlling their entanglement/agglomeration are still big technical challenges to be overcome. The costs of their raw materials and production are also still high. In this work, we propose the use of CNTs grown on oil fly ash to solve these issues. The CNTs of oil fly ash were evaluated as reinforcing materials for some common thermoplastics. High-density polyethylene (HDPE) was mainly reinforced with various weight fractions of CNTs. Xylene was used as a solvent to dissolve HDPE and to uniformly disperse the CNTs. Significantly enhanced mechanical properties of HDPE reinforced at a low weight fraction of these CNTs (1–2 wt.%), mainly the tensile strength, Young’s modulus, stiffness, and hardness, were observed. The tensile strength and Young’s modulus were enhanced by ~20 and 38%, respectively. Moreover, the nanoindentation results were found to be in support to these findings. Polycarbonate, polypropylene, and polystyrene were also preliminarily evaluated after reinforcement with 1 wt.% CNTs. The tensile strength and Young’s Modulus were increased after reinforcement with CNTs. These results demonstrate that the CNTs of the solid waste, oil fly ash, might serve as an appropriate reinforcing material for different thermoplastics polymers.

Tribological Investigation of HDPE-cuttlebone and HDPE-red Coral Composites

In this paper, the tribological properties of cuttlebone (CB)-reinforced high density polyethylene (HDPE) and Red Coral (RC)-reinforced HDPE composites were investigated. The composite specimens were prepared with a hot compression molding machine using different weight proportions of fillers blended with HDPE. The tribological behavior of the composite disks was studied using pin-on-disk tribometer under dry condition against stainless steel M30NW pins. The coefficient of friction as well as wear rate were examined to study the effects of the two fillers on the tribological performance of both composites. After wear tests, different composites were examined using a Scanning Electron Microscope (SEM). It was found that the use of cuttlebone (CB) and Red Coral (RC) as reinforcement improved the tribological properties of HDPE.

English

English

Effect of Cellulosic Waste Derived Filler on the Biodegradation and Thermal Properties of HDPE and PLA Composites

Composites with high density polyethylene (HDPE) and poly(lactic) acid (PLA) matrix have been tested to analyze the effect of natural fillers (wood flour, recycled wastepaper and a mix of both fillers) and temperature on polymer degradation. Composting tests have been performed in both mesophilic (35 °C) and thermophilic (58 °C) conditions. Degradation development has been evaluated through mass variation, thermogravimetric analysis and differential scanning calorimetry. HDPE, as expected, did not display any relevant variation, confirming its stability under our composting conditions. PLA is sensibly influenced by temperature and humidity, with higher reduction of Mw when composting is performed at 58 °C. Natural fillers seem to influence degradation process of composites, already at 35 °C. In fact, degradation of fillers at 35 °C allows a mass reduction during composting of composites, while neat PLA do not display any variation.

Influence of Thermal Ratcheting on the Creep and Mechanical Properties of High-Density Polyethylene

Abstract The objective of this research is to describe the consequence of thermal ratcheting on the long-term creep property of the high-density polyethylene (HDPE) material. The thermal ratcheting phenomenon increases significantly the creep strain of HDPE. The magnitude of the creep strain of HDPE increases by 8% after just 20 thermal cycles between 28 and 50 °C. The creep modulus, which is inversely proportional to the creep strain, depletes further under thermal ratcheting. Both the properties change significantly with the number of thermal cycles. The coefficient of thermal expansion (CTE) of HDPE varies with the applied compressive load, with successive thermal cycles, and with the thermal ratcheting temperature. The impact of thermal ratcheting diminishes with an increase in initial steady creep exposure time period, but still the magnitude cumulative deformation induced is noteworthy. The magnitude of growth in creep strain drops from 8% to 2.4% when thermal ratcheting is performed after 1 and 45 days of steady creep, respectively. There is a notable change in the thickness of the material with each heating and cooling cycle even after 45 days of creep; however, the thermal ratcheting strain value drops by 80% in comparison with the thermal ratcheting strain after 1 day of creep and under similar test conditions.

Influence of Glass Fiber and Calcium Carbonate on The Mechanical and Rheological Properties of High Density Polyethylene (HDPE)

In this study; glass fiber (GF) and calcium carbonate CaCO3 (CC) are fillers used with high density polyethylene (grade EMN 6030). The fillers were mixed with polyethylene by 10-50% w/w to prepare some of polymeric composites mechanical properties such as tensile strength, hardness and Young’s modulus increased with the augmentation filler concentration. However; the elongation strength impact and fracture energy reduced with the augmentation fillers concentration. Moreover, rheological properties as melt index have been studied. The melt index values decreased with the fillers concentration.

DMA analysis, thermal study and morphology of polymethylsilsesquioxane nanoparticles-reinforced HDPE nanocomposite

High-density polyethylene (HDPE) nanocomposites were prepared by a melting-compounding process with a polymethylsilsesquioxane (PMSQ) as nanofiller. In this process, the PMSQ nanoparticles were swollen in an organic solvent using a Ultra-Turrax system and sonication and blended with molten HDPE using a twin-screw extruder. This was followed by solvent removal. Nanocomposites with different PMSQ mass contents from 0 to 1% were prepared. The nanocomposites were characterized with Fourier transformed infrared, transmission electron microscopy, differential scanning calorimetry, scanning electron microscopy and by thermal conductivity. The mechanical and thermomechanical properties of the materials were studied. The HDPE–PMSQ nanocomposites presented a remarkable increase in the elastic modulus (E′) compared to the neat HDPE. The obtained mechanical and thermomechanical properties of HDPE–PMSQ nanocomposites were found to be related to the barrier effect of the PMSQ nanoparticles.

Mechanical and Rheological Properties of High Density Polyethylene Reinforced Polyvinyl Alcohol Fiber Composites

In the current study, high density polyethylene filled polyvinyl alcohol fiber composites have been made via melt compounding process using a twin screw extruder. Four different fiber loadings (0, 5, 10, 20 wt%) together with HDPE matrix were mixed and melt blended with the extruder. The prepared composites were tested for their melt rheological properties, mechanical properties, FT-IR spectra, and water absorption behavior. Rheological test results exhibited that complex viscosity of the composites were higher than the neat HDPE and increased with the increase of PVA loadings. Moreover, the improvement of complex viscosity was more prominent at higher PVA loadings (i.e. PVAC-10 and PVAC-20) than at the lower one (PVAC-5). The flexural modulus and strength were higher for the all composites samples when compared to the neat HDPE, indicating that the incorporation of PVA fiber has successfully improved the mechanical (i.e. flexural) properties of the HDPE/PVA fiber composites. The FTIR analysis results prevailed the appearance of C=O spectrum at 2361 cm-1 that corresponding to carbonyl bond of PVA fiber on the whole composites. Additionally, from the water uptake test, the degree of water absorption of the composites increased with the fiber loadings.

Rotational Moulding and Mechanical Characterisation of Micron-Sized and Nano-Sized Reinforced High Density Polyethylene

Rotational moulding (RM) of plastics is predominantly used to produce hollow, singlepiece products. Polyethylene (PE) in its various forms, is the most commonly used material for this process. Researchers have been conducting numerous experiments trying to incorporate reinforcements attempting to improve the mechanical performance of RM products and overcome the material limitations posed by design parameters. One of the most common problems with reinforcement in RM is the migration of the filler towards the inside of the mould and agglomerations. In order to find a competitive material which is desirable by industry, RM experiments were conducted with various composite reinforcements; high density polyethylene (HDPE), numerous types of glass fibres (GF), carbon fibres (CF) and carbon nanotubes (CNT). In particular, the influence of low weight fractions of reinforcement on the mechanical performance, tensile, flexural and impact properties of HDPE were investigated.

Effect of some organic fillers on the mechanical properties of high density polyethylene

In this paper , the mechanical properties of high density polyethylene (HDPE grade M624) produced by SCPI / Basrah – Iraq , mixed with the wood flour and bagasse as fillers with 10-50 % w/w have been studied . The maximum tensile strength was observed at 10% w/w of fillers ratio . The elongation , impact strength and fracture energy were decreased with increasing of fillers ratio while the Young modulus and hardness were increased .

Evaluation and implementation of High Density Polyethylene liner: Alternative of solution to corrosion-wear problems in flowlines

Failure mechanisms of CO2 corrosion and abrasive wear by production sand have reduced the service life of flowlines and collector lines in Casabe’s mature field located in the middle Magdalena River Valley Basin of Colombia’s Antioquia department, which has required a timely and effective solution. In this work, laboratory tests set to conditions of Casabe’s production fluid were performed to assess abrasive wear and CO2 corrosion resistance on pipeline sections of both HDPE (High Density Polyethylene) and carbon steel API 5L grade X65.
 The results obtained showed that resistance of HDPE to abrasive wear and CO2 corrosion of HDPE is significant, being three times higher as compared with carbon steel. Additionally, material properties of HDPE remained constant in contrast to performance of carbon steel over time tests. This result is due to the toughness and chemical resistance of HDPE.
 Based on these results, a field trial was implemented to pilot-scale for evaluating the performance of HDPE liner in a collector line with a service life between 6 to 9 months, which collect fluids of different flowlines from producing wells.
 After 12 months in service, the field trial of the liner assessed through visual inspection and DSC tests revealed that HDPE liner exposed at multiphasic fluid conditions with production sand remained stable without evidence of swelling, blistering, softening or changes in its geometry associated with liquid hydrocarbon absorption in its physical structure. This was also evidenced in the results of melting temperature and crystallinity obtained from DSC tests before and after exposure to field conditions. Moreover, pilot tests with HDPE lining after six years of service still operate successfully.

Characterization of sorption properties of high-density polyethylene using the poly-parameter linearfree-energy relationships

High-density polyethylene (HDPE) is a known sorbent for non-ionic organic compounds in technical applications. Nevertheless, there is little information available describing sorption to industrial HDPE for a broad range of compounds. With a better understanding of the sorption properties of synthetic polymers, environmental risk assessment would achieve a higher degree of accuracy, especially for microplastic interactions with organic substances. Therefore, a robust methodology for the determination of sorbent properties for non-ionic organic compounds by HDPE is relevant for the understanding of molecular interactions for both technical use and environmental risk assessment.In this work, sorption properties of HDPE material used for water pipes were characterized using a poly-parameter linear free-energy relationship (ppLFER) approach. Sorption batch experiments with selected probe sorbates were carried out in a three-phase system (air/HDPE/water) covering an aqueous concentration range of at least three orders of magnitude. Sorption in the concentration range below 10−2 of the aqueous solubility was found to be non-linear and the Freundlich model was used to account for this non-linearity. Multiple regression analysis (MRA) using the determined distribution coefficients and literature-tabulated sorbate descriptors was performed to obtain the ppLFER phase descriptors for HDPE. Sorption properties of HDPE were then derived from the ppLFER model and statistical analysis of its robustness was conducted. The derived ppLFER model described sorption more accurately than commonly used single-parameter predictions, based i.e., on log Ko/w. The ppLFER predicted distribution data with an error 0.5 log units smaller than the spLFERs. The ppLFER was used for a priori prediction of sorption by the characterized sorbent material. The prediction was then compared to experimental data from literature and this work and demonstrated the strength of the ppLFER, based on the training set over several orders of magnitude.