High Density Polyethylene Mixtures Research Articles

Tensile properties of sisal fiber/recycled polyethylene (high density) composite: Effect of fiber chemical treatment

This study scrutinizes the influence of fiber treatment on tensile properties of sisal fibers reinforced in polyethylene (high density) composite. Alkalization is performed on sisal fibers and followed by maleic anhydride (MA) as coupling agent treatment. Treated sisal fibers are reinforced into 50-50% mixture of fresh and recycled high density polyethylene (HDPE) matrix. The tensile properties of composites are compared with 50-50% mixture of HDPE samples. Tensile strength of sisal fiber/HDPE composite containing 7.5, 15, 22.5 and 30 wt.% treated sisal fibers is respectively lower by 20%, 25%, 24.5% and 50% when compared to sample with 50-50 mixture of fresh and recycled HDPE. Among from the all samples 50-50 mixture of HDPE gives highest tensile strength. SEM images showed that in all composites the main failure mechanisms responsible for tensile failure is fiber pull-out apart from some other secondary mechanisms like fiber breakage and fiber delamination.

Study of the Thermal, Rheological, Morphological and Mechanical Properties of Biocomposites Based on Rod-Of Typha/HDPE Made up of Typha Stem and HDPE

The thermal, rheological and morphological properties of composite biomaterials made with mixture of high density polyethylene and typha rod powder (RD) were evaluated. The dynamic mechanical behavior of the samples was studied with 25%, 35% and 45% typha stem powder concentrations. The viscoelastic properties are mainly related to the nature of the polymer and the typha stem powder. Storage (G') and loss (G") moduli increased significantly, depending on the amount of powder in the molten mixture. After a viscosity increase was noticed in low frequency, it decreased in high frequencies, which demonstrates the pseudo-plasticity effect. Morphological and thermal characterization results have shown the dispersion state of the powder and its ability to modify the kinetics crystallization of biocomposites.

The Effects of Micro- and Nano-Fillers’ Additions on the Dynamic Impact Response of Hybrid Composite Armors Made of HDPE Reinforced with Kevlar Short Fibers

ABSTRACTHybrid composite armors consisting of Kevlar short fibers reinforced high-density polyethylene were prepared and the effects of the addition of micro and nano-fillers on the dynamic impact response and the energy absorption under ballistic impact were investigated. Five groups of specimens were manufactured using compression molding of pellets containing mixtures of high-density polyethylene and the reinforcing materials. The first group consist of high-density polyethylene reinforced with 10 wt% Kevlar pulp (KN-1). The rest are hybrid composites created by the addition of 20 wt% of micro and nano-fillers. The natural micro-fillers used are particles of chonta palm wood (KN-2) and potato flour (KN-3). The synthetic nanofillers are colloidal silica (KN-4) and gamma alumina (KN-5). Microstructure (scanning electronic microscope) and compositional (energy-dispersive spectroscopy) analysis of the hybrid composites were carried out to evaluate matrix-reinforcements-interface. The fabricated composites plates were subjected to high velocity impact using split Hopkinson pressure bar system and ballistic impact, according to NIJ standard–0101.06 for ballistic resistance. Significant stiffness improvements of up to 43.5% were achieved as a result of the addition of synthetic nano-particles to Kevlar fiber reinforced high-density polyethylene. X-ray diffractometer analysis revealed that the crystalline structure of the Kevlar reinforced high-density polyethylene is unaffected by addition of the nano-particles as fillers. However the intensity of the crystalline peaks decreased depending on the type of the added fillers. The results of dynamic impact test using split Hopkinson pressure bar revealed improved impact resistance by addition of synthetic nanofillers (silica and alumina). The results of the ballistic impact test showed the gamma alumina nano-particles (KN-5) exhibited the highest energy absorption capability. The results of these investigations indicate that hybridization Kevlar short fibers reinforced high-density polyethylene by micro and nano-fillers addition enhances the stiffness, impact resistance and ballistic energy absorption capability of the composites.

Upgrading of high-density polyethylene and light cycle oil mixtures to fuels via hydroprocessing

The joint valorization of high-density polyethylene (HDPE) and light cycle oil (LCO) has been studied via hydroprocessing with the aim of valorizing the HDPE and reducing the sulfur and polyaromatic contents in the LCO. Experiments have been carried out in a batch type reactor under the following conditions: 320–400°C; 80bar; feed:catalyst mass ratio, 20:1; LCO:HDPE mass ratio, 10:1. CoMo/Al catalyst showed higher LCO hydrodesulfurization activity than the other tested catalysts (NiMo/SiAl and NiW/HY), reaching a hydrodesulfurization conversion of 99.3wt% (72ppm of sulfur in the liquid product) at 400°C. Furthermore, a moderate dearomatization was obtained, reaching a polyaromatic conversion of 76wt%. In the hydroprocessing of LCO and HDPE mixture, the joint feeding lightly increases hydrodesulfurization conversion and has no significant impact on product distribution, with HDPE conversion being 31wt%. These results are promising for valorizing waste plastics by incorporating into a first LCO hydroprocessing stage. The hydrodesulfurizated liquid product should be treated in a second hydrocracking stage using a noble metal catalyst supported on strong acid functions.

Hydrogen-rich gas production by continuous pyrolysis and in-line catalytic reforming of pine wood waste and HDPE mixtures

The continuous pyrolysis-reforming of pine sawdust and high density polyethylene mixtures (25, 50 and 75wt% HDPE) has been performed in a two-stage reaction system provided with a conical spouted bed reactor (CSBR) and a fluidized bed reactor. The influence HDPE co-feeding has on the conversion, yields and composition of the reforming outlet stream and catalyst deactivation has been studied at a reforming temperature of 700°C, with a space time of 16.7gcatmingfeeding−1 and a steam/(biomass+HDPE) mass ratio of 4, and a comparison has been made between these results and those recorded by feeding pine sawdust and HDPE separately. Co-feeding plastics enhances the hydrogen production, which increases from 10.9g of H2 per 100g of feed (only pine sawdust in the feed) to 37.3g of H2 per 100g of feed (only HDPE in the feed). Catalyst deactivation by coke is attenuated when HDPE is co-fed due to the lower content of oxygenated compounds in the reaction environment. The higher yield of hydrogen achieved with this two-step (pyrolysis-reforming) strategy, its ability to jointly valorise biomass and plastic mixtures and the lower temperatures required compared to gasification make this promising process for producing H2 from renewable raw materials and wastes.

Structural, thermal, and gas transport properties of HDPE/LLDPE blend‐based nanocomposites using a mixture of HDPE‐g‐MA and LLDPE‐g‐MA as compatibilizer

Nanocomposites based on high density polyethylene (HDPE)/linear low density polyethylene (LLDPE) blend were prepared by melt compounding in a twin‐screw extruder using organoclay (montmorillonite) as nano‐filler and a 50/50 wt% mixture of maleic anhydride functionalized high density polyethylene (HDPE‐g‐MA) and linear low density polyethylene (LLDPE‐g‐MA) as the compatibilizing system. The addition of a maleated polyethylene‐based compatibilizing system was required to improve the organoclay dispersion in the HDPE/LLDPE blend‐based nanocomposite. In this work, the relationships between thermal properties, gas transport properties, and morphology were correlated. The compatibilized nanocomposite exhibited an intercalated morphology with a small number of individual platelets dispersed in the HDPE/LLDPE matrix, leading to an significant decrease in the oxygen permeation coefficient of the nanocomposites. A decrease in the carbon dioxide permeability and oxygen permeability with increase of nanoclay was observed for the compatibilized nanocomposites. The carbon dioxide permeability of the compatibilized nanocomposites was lower than the carbon dioxide permeability of the uncompatibilized nanocomposites even with the low intrinsic barrier properties of the compatibilizer. These effects were attributed to a good dispersion of the inorganic filler, good wettability of the filler by the polymer matrix, and strong interactions at the interface that increased the tortuous path for diffusion. Theoretical permeability models were used to estimate the final aspect ratio of nanoclay in the nanocomposite and showed good agreement with the aspect ratio obtained directly from TEM images. POLYM. ENG. SCI., 56:765–775, 2016. © 2016 Society of Plastics Engineers

Газопроницаемость смесей полиолефинов, содержащих стеклянный пластинчатый наполнитель

In article investigated the influence of the glass fillers on the barrier properties of high density polyethylene mixtures to oxygen, carbon dioxide and water vapor.

Tribo-Aero-Electrostatic Separator for Ternary Mixtures of Granular Plastics

This paper presents a comprehensive study of an electrostatic separation device for the recycling of granular plastic materials from waste electrical and electronic equipment (WEEE). The peculiarity of this system is the association of two charging techniques: 1) fluidized bed (dynamic charger) and 2) sliding on inclined plates (static charger)—and two superposed separation units, in order to achieve the selective sorting of a granular mixture composed of three different species of insulating materials. The tests were performed on a mixture of high-density polyethylene (HDPE), polyvinyl chloride (PVC), and polycarbonate (PC). A set of tribocharging experiments was conducted for each material, so that to choose the nature of the walls of the static charger. The analysis of the purity of separated products was performed using an image processing program written in MATLAB. High-purity separation (85%, 95%, and 75% for the PVC, PC, and HDPE products, respectively) was obtained at a recovery rate beyond 80%.

Kinetic Analysis on Catalytic Co-Gasification of Rubber Seed Shell and High Density Polyethylene Mixtures

In this paper, the catalytic co-gasification of rubber seed shell and high density polyethylene mixtures (0.2:0.8 weight ratio of HDPE:RSS) are investigated using a non-isothermal thermogravimetric analysis (TGA) system in a range of heating rates of 10, 20, 30 and 50 K/min within the temperature range of 323-1173 K. The argon gas is supplied at a flowrate of 100 ml/min and the steam is generated from superheater at 383 K. The steam is injected at flowrate of 300 μL/hour into the TGA system. A commercial nickel powder is used as the catalyst for the gasification process. The thermal decomposition behavior and synergistic effect of the HDPE/RSS mixture are investigated. The activation energy, EA and pre-exponential factor, A are determined based on one step integral method.

Gasification conversion and char reactivity of rubber seed shell and high density polyethylene mixtures using steam Co-Gasification process

a Biomass Processing Lab, Centre for Biofuel and Biochemical Research, Green Technology MOR, Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Tronoh 31750, Malaysia b The Petroleum Institute, P. O. Box 2533, Abu Dhabi, United Arab Emirates c Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Tronoh 31750, Malaysia drsuzana_yusuf@petronas.com.my

Evidence of Mie scattering at terahertz frequencies in powder materials

We present experimental results as well as modelling concerning terahertz (THz) wave scattering by powder materials with grain size of the order of the wavelength. The studied material is a mixture of high density polyethylene and fructose powders, whose grain size is varied from a sample to another one while the volume concentration is kept constant. Experimental data are recorded with a THz time-domain spectroscopy set up. The scattering contribution to the total propagation loss in such powders shows a resonant behaviour for grain size roughly equal to the THz wavelength, for which it reaches 80%–90% of the total loss. Modelling using Mie theory allows us to well describe the absorption and scattering phenomena.

Comparative studies on catalytic and non-catalytic co-gasification of rubber seed shell and high density polyethylene mixtures

The thermal degradation behavior of rubber seed shell, high density polyethylene waste, and the binary mixtures of high density polyethylene and rubber seed shell (0.2:0.8 weight ratio) are compared in pyrolysis, gasification, and catalytic gasification process at different heating rate of 10, 20, 30 and 50 K min−1 in temperature range of 323–1173 K using thermogravimetric analysis equipment. It is observed that there are one, two, and three stages of decomposition occurring in high density polyethylene, rubber seed shell, and the binary mixtures respectively regardless of the process involved. The activation energies, EA and pre-exponential factor, A are generated using one step integral method based on first order rate of reaction. Besides that, the synergistic effect on the binary mixtures is also investigated for the three different processes involved. It is found that the EA and A values for the binary mixtures are lower than the pure high density polyethylene but comparable to pure rubber seed shell regardless of the processes involved. In addition, it is also observed that the EA and A values are slightly lower when catalyst is added in the binary mixtures compared to the absence of catalyst in the gasification process.

Comparison Studies of Criado and Coats-Redfern Methods for Co-Gasification of Rubber Seed Shell with High Density Polyethylene Mixtures

In this present study, the gasification kinetics of rubber seed shell, high density polyethylene, and their mixtures (20/80 and 40/60 weight ratio of HDPE/RSS) are investigated using a non-isothermal thermogravimetric analysis (TGA) system at heating rate of 10 K/min in the temperature range of 323-1173 K. The argon gas is supplied at a flowrate of 100 ml/min and the steam is generated from superheater at 383 K. The steam is injected at flowrate of 300 μL/hour into the TGA system. The Criado and Coats-Redfern methods are used to investigate the reliability of the determined value of the activation energy, EA from the experimental data of TGA. The interaction of solid-phase components based on the mentioned experimental conditions is also studied.

The Mechanical Properties of a Mixture of High Density Polyethylene and Calcium Carbonate Dedicated for Packaging

Packaging made of polymeric materials is one of the most important branches of polymer processing. A very essential task which is to be solved in this area, is searching for new materials which would allow for lowering the cost while still maintaining good mechanical properties. In the current paper the attempt to decrease the cost of the HDPE intended for blow moulding of packaging by admixing CaCO3 filler is presented. The dependence of mechanical properties upon the filler content is also shown.

Fabrication of a novel polyethylene/starch blend through mediation of a high‐energy ball milling process: Mechanical properties and formation mechanism

AbstractHigh‐energy ball milling (HEBM) was performed before melt mixing to fabricate a novel blend containing 85 wt % of a high density polyethylene (HDPE) and 15 wt % of a maize starch, using neither compatibilizer nor plasticizer materials in the blend formulation. Scanning electron microscopy and rheometry results revealed a strong interface between the two phases of the blend. Formation of the interface with high strength was ascribed to the grafting reactions, taking place between the phases during the HEBM process, and corroborated by Fourier transform infrared characterizations. A possible formation mechanism for the starch‐grafted polyethylene was proposed based on the measurements and comprehensive analysis. Interestingly enough, when compared to HDPE mixtures which contained the same amount of the starch, but were made only by conventional melt blending, the ball mill‐mediated sample showed superior mechanical and biodegradation properties. These properties enhancements were related to both the HDPE/starch strong interface and the damaged starch originated by the mechanical action of the milling process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Recycled HDPE-tetrapack composites. Isothermal crystallization, light scattering and mechanical properties

ABSTRACTIn this research the thermal and mechanical properties of composites based on recycled high-density polyethylene (HDPE) and recycled Tetrapak have been investigated. The matrix and filler are recovered from landfills. Multicolor HDPE mixtures, with varying concentration of tetrapack flakes, are hot pressed, as well as single color HDPE flakes. Previous studies determine that the nature of the pigment (organics vs. inorganics) strongly influence the mechanical behavior of multicolor HDPE-tetrapack composites. Thus, this research focuses on single color HDPE hot pressed plaques. The kinetics of crystallization under isothermal conditions is determined by differential scanning calorimetry (DSC). The results show that the crystallization kinetics obeys the Avrami theory, and that the Avrami exponent is 1, irrespective of the pigment in use. Small-angle light scattering is applied to investigate the internal structure of the pigmented HDPE. SALS patterns show that the samples exhibited oriented morphologies. However, after melting and slow cooling under pressure the samples exhibit an isotropic morphology. This is confirmed by polarized optical microscopy. Mechanical properties such as Young’s modulus, yield stress and ultimate tensile stress are obtained under uniaxial tensile deformation at room temperature. For the single color HDPE plaques the Young’s modulus is reduced (after melting), suggesting that the anisotropic molecular chains contribute to the higher value of Young’s modulus.

Synergetic pyrolysis of high density polyethylene and Jatropha and Karanj cakes: A thermogravimetric study

Coprocessing behavior of mixtures of high density polyethylene (HDPE) and deoiled cakes of Jatropha and Karanja was studied by thermogravimetric analyses under dynamic conditions in the presence of nitrogen atmosphere and compared with those of individual materials. Experiments were carried out in the temperature range of ambient temperature to 900 °C at two heating rates (5 and 20 °C/min). Kinetic studies indicated activation energies for HDPE decomposition to be 235 and 258 kJ/mol at heating rates of 5 and 20 °C/min, respectively. Values of activation energy for pyrolysis of cakes of Jatropha and Karanj and those for cake-HDPE mixtures varied with the rate of heating as well as with the three temperature ranges. This variation has been explained based on the materials’ decomposition behavior. Reduction in activation energy for decomposition of the mixtures implies synergetic effects to be existing when two materials are coprocessed together.

Processing and thermal, mechanical and morphological characterization of post-consumer polyolefins/thermoplastic starch blends

Mixtures of high density polyethylene (HDPE) and polypropylene (PP), both post-consumer polymers were blended with thermoplastic starch (TPS). Corn starch plastification was carried out by extrusion with glycerin addition. The behaviour of TPS produced was investigated in the processing and thermal, mechanical and morphology characterization of post-consumer HDPE/PP blends (100/0, 75/25, and 0/100 wt.%) in different proportions of TPS (30%, 40% and 50% wt.%) by melting flow index (MFI), tensile property measurements, and scanning electron microscopy (SEM), respectively. The addition of TPS reduced the MFI of PP and increased of HDPE and HDPE/PP blends. TPS also decreased the tensile strength and elongation at break, and increased the rigidity of the materials. SEM showed separation of phase between the poliolefins and TPS.

石炭とプラスチックのコプロセッシングに及ぼすＰＶＣの影響

The coprocessing with coal is one of the beneficial technologies to convert waste plastics into alterna-tive liquid hydrocarbon for fuel oil and chemical feedstock. The waste plastics having high H/C ratio are expected to play the role of hydrogen source. On the other hand, the waste plastics include chlorine-contain-ing plastic such as polyvinyl chloride (PVC). Hydrogen chloride generated from pyrolysis of PVC causes the problems such as the corrosion of equipment. In the coprocessing reaction, it is expected that the hydrogen chloride is captured by the minerals in coal.In this paper, the influence of PVC on the coprocessing with Wyoming subbituminous coal and the mixture of high density polyethylene, polypropylene, polystyrene, and PVC was investigated under decalin solvent.A part of hydrogen chloride generated from PVC was fixed as chlorides by the minerals in coal, but the rest formed chlorinated organic compounds. These reactions occured competitively. When a sufficient amount of hydrogen chloride was not captured, the chain reactions of polymer radicals were inhibited by chlorine radical. This inhibitation resulted in the increase of heavy oil yield. To avoid it, the optimization of the raito of coal and plastics was desired.

The effect of PVC and/or PET on thermal degradation of polymer mixtures containing brominated ABS

Complex polymer mixtures of high density polyethylene (PE), polypropylene (PP), polystyrene (PS) and acrylonitrile–butadiene–styrene copolymer containing a polybrominated epoxy type flame retardant (ABS-Br) were thermally degraded at 450 °C in the presence of PVC and/or PET. It was found that besides a large amount of styrene and benzene derivatives (more than 50 wt%), the pyrolysis oils contained about 1000 ppm nitrogen, 1000–4000 ppm bromine, 5000–5200 ppm chlorine and 800–1300 ppm oxygen, their amount and distribution depending on the composition of polymer mixture. The effect of PVC manifests especially in the early stages of decomposition while PET influenced also the late stages of the process. ABS copolymer and its flame retardant interact with both PVC and PET during thermal decomposition.