High-density Polyethylene Content Research Articles

Deformation mechanism of high-density polyethylene/liquid paraffin films during stretching

In this study, the deformation mechanism of high-density polyethylene (HDPE)/liquid paraffin (LP) films is systematically investigated. The findings demonstrates that the structural changes are significantly influenced by the LP content. Pure HDPE displays a pronounced cavitation phenomenon, whereas HDPE/LP films deform without cavitation. The yielding mechanism observed in HDPE/LP films is related with the extension of molecular chains and rotation/shearing of the lamellae. At high strains, pure HDPE and LP content lower than 20 % form a fibril-like crystal structure. However, samples with LP content exceeding 40 % form a highly oriented and periodically arranged fibrillar crystal structure. Last but not least, distinctly different cross-section morphologies are observed after extraction for HDPE/LP films. When LP content is below 20 %, the films exhibit a non-porous morphology. When the LP content exceeds 40 %, a loose porous morphology is observed after extraction. These findings provide valuable insights into the structural evolution and deformation behavior of HDPE/LP films under mechanical stress.

Effects of process conditions and nano-fillers on the cell structure and mechanical properties of co-injection molded polypropylene-polyethylene composites

Compared with traditional injection foaming, co-injection foaming serves as a method to prepare products with high-quality surfaces and enhanced mechanical properties, demonstrating excellent technical advantages and economic benefits. The effects of high-density polyethylene (HDPE) content, foaming agent content, melting temperature of core material, and nano-organic montmorillonite (OMMT) content on the cell structure, mechanical properties, and crystallization behavior of isotactic polypropylene (iPP)/HDPE composite foam prepared by co-injection foaming were systematically studied. At a foaming agent content of 2 wt.%, HDPE content of 30 wt.%, OMMT content of 3 wt.%, and the melting temperature of core material of 190 °C, the composite foam exhibited a cell size measuring 85 μm, a cell density of 2.5 × 105 cells/cm3, a tensile strength of 25.8 MPa, and an impact strength of 12.5 kJ/m2. The addition of HDPE reduced the crystallinity of iPP matrix, while enhancing the solubility of carbon dioxide within the matrix. The non-miscible interface between HDPE and iPP helped reduce the energy barrier for cell nucleation. Furthermore, the introduction of OMMT as a nucleating agent in iPP/HDPE composite material dramatically decreased the energy barrier for cell nucleation. These synergistic effects result in foam with the smaller cell size and the higher cell density, exhibiting excellent comprehensive mechanical properties. This work provides a feasible method for preparing composite foam with excellent comprehensive performance.

Comparative Analysis of Kerosene Grade Fuel from Pyrolysis of HDPE and LDPE Waste Plastics

To curb the menace of plastic waste and energy crisis, this study investigated the conversion of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) grades of plastics to kerosene. Plastics sourced from dumpsites within Port Harcourt metropolis in Rivers State, Nigeria were shredded and pyrolyzed (thermally degraded under inert condition at a temperature range of 350-400oC). The obtained hydrocarbon liquid was distilled using distillation column at a temperature range of 150-270oC and characterised to evaluate the physico-chemical parameters such as flash point, density, copper corrosion, and calorific value and compared against the acceptable standard. The result showed that these properties were within the permissible limit. However, the sulphur content and smoke point of HDPE and LDPE were above and below the limits, respectively. The GC-MS and GC-FID results of kerosene samples obtained from both grades of plastics indicates that the product comprised C9 to C17 grades.

From Waste Vegetable Oil to a Green Compatibilizer for HDPE/PA6 Blends.

When properly compatibilized, the blending of polyethylene (PE) and polyamide (PA) leads to materials that combine low prices, suitable processability, impact resistance, and attractive mechanical properties. Moreover, the possibility of using these polymers without prior separation may be a suitable opportunity for their recycling. In this work, the use of an epoxidized waste vegetable oil (EWVO) was investigated as a green compatibilizer precursor (CP) for the reactive blending of a high-density PE (HDPE) with a polyamide-6 (PA6). EWVO was synthesized from waste vegetable cooking oil (WVO) using ion-exchange resin (Amberlite) as a heterogeneous catalyst. HDPE/PA6 blends were produced with different weight ratios (25/75, 75/25, 85/15) and amounts of EWVO (1, 2, 5 phr). Samples with WVO or a commercial fossil-based CP were also prepared for comparison. All the blends were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), rheology, and mechanical tests. In the case of HDPE/PA6 75/25 and 85/15 blends, the addition of EWVO at 2 phr showed a satisfactory compatibilizing effect, thus yielding a material with improved mechanical properties with respect to the blend without compatibilizer. On the contrary, the HDPE/PA6 25/75 ratio yielded a material with a high degree of crosslinking that could not be further processed or characterized. In conclusion, the results showed that EWVO had a suitable compatibilizing effect in HDPE/PA6 blends with high HDPE content, while it resulted in unsuitable for blends with high content of PA6.

The compression characteristics and lateral earth pressure coefficient of sand–HDPE mixtures

In recent decades, considerable attempts through geotechnical study have been made to reduce plastic waste by recycling and reuse. The aim of this study was to reuse waste plastic mixed with sand for geotechnical application. To this end, large-scale oedometer experiments were carried out to examine the compressibility of Bandar-e Anzali sands stabilised with plastic-waste-originated high-density polyethylene (HDPE). Bandar-e Anzali is a populated coastal city in the vicinity of the Caspian Sea (northern Iran). Large-scale oedometer and direct shear tests were performed to study the applicability of HDPE chips mixed with sand at various HDPE contents (0, 2, 4, 6 and 8%). Based on the experimental tests, the addition of plastic waste to the soil improved the soil's strength, significantly raised its compressibility and decreased the undrained elasticity modulus. By adding 8% HDPE, the constrained compression modulus decreased to 50% at a pressure of 300 kPa due to the elastic deformability of HDPEs. However, at higher relative density, adding HDPE by more than 4% did not affect the coefficient of lateral earth pressure at rest.

Physico‐chemical characterization and degradation analysis of mineral paper: Impact of accelerated weathering and aerobic biodegradation

AbstractMineral paper, a synthetic paper‐like material primarily composed of ground calcium carbonate (CaCO3) and a small amount of high‐density polyethylene (HDPE), has emerged as an important alternative to traditional paper and board due to the increasing demand for pulp and paper and the shortage of trees and fibrous material in many regions worldwide. This study aimed to investigate the impact of accelerated weathering and aerobic biodegradation on three different types of mineral papers. The specimens underwent 1000 h of accelerated weathering using a Gardner weathering device and were also buried in soil at a depth of 5 cm for 3 months with regular watering conditions for biodegradability testing. Physico‐chemical characterizations such as optical (whiteness), surface (roughness, contact angle, and paper topography), and chemical properties of the samples were studied before and after the artificial weathering and biodegradation tests. The results revealed a visible color change (darkening) in mineral papers, with an increase in HDPE content leading to a darker color after weathering and biological degradation. However, there were no significant differences in the color change between weathering and soil‐burial tests. The biodegradability test resulted in a decrease in ash content due to the demineralization process. All samples' surface roughness was reduced after weathering and biodegradation tests. The FT‐IR and EDS analyses confirmed the presence of calcium, carbon, and oxygen elements in all three samples, indicating a large amount of calcium carbonate in the mineral papers. The scanning electron microscopy (SEM) images showed the creation of micro holes and cracks on the surface of the samples after weathering and biodegradation. Overall, the soil‐burial test showed more degradation than the weathering test.Highlights The influence of weathering and biodegradation of mineral papers were studied After soil‐burial test, the ash content decreased due to the demineralization After weathering, micro cracks were created on the surface of the samples The degradation of the soil‐burial test was more than the weathering test Mineral papers most likely contain carbonate calcium and HDPE

Preparation and characterization of plywood panels using recycled HDPE as a formaldehyde-free adhesive: A comparative study

Formaldehyde-based resins such as urea-formaldehyde (UF) are the most widely used adhesives in the plywood industry. However, due to the concerns about formaldehyde toxicity, there is a need to develop formaldehyde-free adhesive materials. Therefore, the present study aimed to minimize or eliminate the harmful effects of UF resin by using recycled high-density polyethylene (HDPE) from post-consumed fruit packing boxes as a nontoxic adhesive. Three-layer plywood panels using poplar veneers and recycled HDPE films were prepared. UF was used as a control adhesive for the comparison. The influence of three variable parameters in terms of HDPE content (from 80 to 320 g/m2), hot-pressing temperature (from 140 to 180 °C), and pressing duration (from 3 to 8 min) on the properties of plywood panels were evaluated. For evaluation, physical properties, namely water absorption (WA), thickness swelling (TS), and mechanical properties, namely modulus of elasticity (MOE), modulus of rupture (MOR), and glue-line shear strength of the samples, were studied. The findings of this work confirmed that HDPE films gave the values of mechanical properties of plywood panels comparable to those obtained with UF adhesive, even though the adhesive content and pressing time were lower than when the UF adhesive was used. The obtained bonding strength values of HDPE-bonded plywood panels ranged from 0.82 to 1.60 MPa and met the requirement for the European Standard EN 314-2. According to FE-SEM micrographs, the fractured surface of plywood panels with 240 g/m2 of HDPE displayed a homogeneous cross-section area, and a large amount of HDPE was attached to the veneer surfaces. It was found that the average mechanical properties tended to increase with an increase in the pressing temperature and time. The type of adhesive had a significant effect on WA and TS. The smallest values of WA and TS were observed in plywood samples using high contents of HDPE films (240 and 320 g/m2). The optimum conditions were an HDPE loading of 240 g/m2, a hot-pressing temperature of 160 °C, and a hot-pressing time of 5 min. The overall results showed that recycled HDPE had enough potential to reuse as a promising adhesive for the environmentally-friendly plywood manufacturing.

Development of Foam Fly Ash Geopolymer with Recycled High-Density Polyethylene (HDPE) Plastics.

Adapting sustainable construction, which involves responsible consumption of natural resources and reducing carbon emissions, could be a unified action to address the intensifying effects of global warming and the increasing rate of waste pollution worldwide. Aiming to lessen the emission from the construction and waste sector and eliminate plastics in the open environment, a foam fly ash geopolymer with recycled High-Density Polyethylene (HDPE) plastics was developed in this study. The effects of the increasing percentages of HDPE on the thermo-physicomechanical properties of foam geopolymer were investigated. The samples' measured density, compressive strength, and thermal conductivity at 0.25% and 0.50% HDPE content was 1593.96 kg/m3 and 1479.06 kg/m3, 12.67 MPa and 7.89 MPa, and 0.352 W/mK and 0.373 W/mK, respectively. Obtained results are comparable to structural and insulating lightweight concretes with a density of less than 1600 kg/m3, compressive strength of greater than 3.5 MPa, and thermal conductivity of less than 0.75 W/mK. Thus, this research concluded that the developed foam geopolymers from recycled HDPE plastics could be a sustainable alternative material and be optimized in the building and construction industry.

Influence of high-density polyethylene content on the rheology, crystal structure, and mechanical properties of melt spun ultra-high-molecular weight polyethylene/high-density polyethylene blend fibers

High-density polyethylene (HDPE) content significantly influences the structure and mechanical properties of ultrahigh molecular weight polyethylene (UHMWPE)/HDPE blend fibers. The molecular chain disentanglement and crystallization characteristics of as-spun filaments and fibers and how the structure affects the final mechanical properties of the fibers were thoroughly studied by adding different contents of HDPE. Dynamic mechanical analysis (DMA) and rheological analysis indicated that the molecular entanglement decreased with increasing HDPE content, improving the UHMWPE melt processability. Sound velocity orientation (SVO) studies indicated that the UHMWPE/HDPE as-spun filaments and fibers with an HDPE content of 40 wt% (U6H4) had a higher molecular chain orientation level. Furthermore, differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) analyses indicated that U6H4 had the highest crystallinity and the thinnest grains in the axial direction, respectively. The compact crystal structure and fully stretched molecular chains of U6H4 yielded the best mechanical properties. The present work disclosed the effect mechanism of HDPE contents on the preparation and properties of UHMWPE/HDPE fibers, which provided an effective and universal strategy for manufacturing high-strength UHMWPE/HDPE fibers with the melt spinning method.

Thermal, rheological, and mechanical characterization of compression and injection molded ultra‐high molecular weight polyethylene, high density polyethylene, and their blends

AbstractTensile and impact test samples of ultra‐high molecular weight polyethylene (UHMWPE), high‐density polyethylene (HDPE), and their blends at various UHMWPE/HDPE weight ratios were prepared via compression molding and injection molding for thermal, rheological, and mechanical characterization. A twin‐screw extruder with either a tapered die with air‐cooling or a regular die was used to compound and extrude the materials prior to pelletization and molding. To the best of our knowledge, there has been no publication on pelletizing neat UHMWPE using a regular extruder. The differential scanning calorimetry analysis suggested the occurrence of re‐crystallization and co‐crystallization for all the blends. The rheology test confirmed that all the blends exhibited a solid‐like behavior and the degree of compatibility increased with increasing HDPE content in the blends. A strong synergistic effect was observed the blends possessed a higher tensile and impact strength than their neat UHMWPE and HDPE counterparts. The compression molded (95/5) UHMWPE/HDPE samples extruded using the tapered die yielded the highest tensile strength (50.1 MPa), which was about 40% higher than that of the neat UHMWPE samples. The best composition of these blends for compression and injection molded parts is 10% HD and 50% HD, respectively.

Analysis of the influence of additional plastic waste (HDPE) as Mixed Asphalt AC-WC on Marshall Parameters

<p>Flexible pavement structures that use asphalt as a binder are currently the mainstay of the Indonesian people because of their large load-bearing capacity and economical construction costs. One type of flexible pavement used is asphalt concrete with the top surface layer or Asphalt Concrete Wearing Course (AC-WC). The use of asphalt from the petroleum refining process is one of the problems because its availability is decreasing. However, the condition of the road pavement which has a limited life requires periodic repairs to maintain the condition of the road. In addition, there are also problems regarding the processing of plastic waste which is still not optimal. Based on data published by the National Waste Management Information System in 2020 as much as 18.3% of the total waste generated. This figure increased by 2.3% from the previous year. Sukoharjo Regency also experienced an increase in sales of plastic waste by 1.16% from 14.04% (in 2019) and now to 15.20% (in 2020). Plastic is one type of polymer in the thermoplastic polymer group which is processed by organic chemical compounds. One type of plastic that is often used is High Density Polyethylene (HDPE) which has strong, light and flexible properties that can soften at a temperature of 130-137"℃" and harden again if. In this study, HDPE plastic bag waste was used as a pure asphalt substitute with variations in the proportion of substitution of 2%, 4%, 6%, 8%, 10%. Where this study aims to analyze the effect of adding HDPE plastic waste as a mixture of AC-WC asphalt on asphalt parameters. From the research conducted, the use of asphalt content of choice is 5.7%. With the results of the mixture with HDPE asphalt mixture HDPE has increased with the addition of variations of HDPE. The flexibility of HDPE asphalt mixture decreased according to the flow meter reading. At a content of 2% HDPE has the largest percentage of VIM, flow, and proportion of VMA, but has the lowest value and percentage of VFB. The best range of HDPE content is in the percentage of 4%-6% because it can increase the value of a more flexible mixture and optimal asphalt absorption. The use of HDPE plastic waste is an alternative in waste treatment and can reduce the use of asphalt. It can be concluded that HDPE plastic bags can be used as an alternative to bitumen substitutes that meet the requirements of Bina Marga 2018 Revised 2nd Edition.</p>

Thermal and Crystallization Behaviour of Polyphenylene Sulfide in Engineering Polymer Blends with HDPE

Abstract The thermal and crystallization behaviour of polyphenylene sulfide (PPS) in its blends with high density polyethylene (HDPE) is reported. Three grades of HDPE ranging in MFI from 0.4 to 52 were used in the investigation. The effect of composition and molecular weight of HDPE on the crystallization process and morphology of PPS in the blends has been investigated by the technique of Differential Scanning Calorimetry (DSC). In the blends, PPS crystallizes in presence of molten HDPE. It is observed that the morphology of PPS in terms of crystallite size and crystallite size distribution in the blends is significantly affected by blending with HDPE. The temperature onset of melting was found to increase with increasing HDPE content and the melting peak width was found to decrease with increasing HDPE content. This indicates a larger crystallite size and a narrower crystallite size distribution of PPS in blends. The effect is more pronounced in HDPE-rich compositions. The extent of the variation in the temperature onset of melting and peak width were comparable for all the grades of HDPE. The degree of crystallinity of PPS in the blends is reduced significantly (55–70%) in HDPE-rich blends. Therefore, it is concluded that the crystallization of PPS is affected by the presence of HDPE melt. The crystallization scans of PPS in the blends, obtained in the cooling mode, did not show any evidence of accelerated nucleation. On the other hand, a marginal reduction in the temperature onset of crystallization was observed. The temperature range of crystallization of PPS in the blends was found to be less for all compositions except for 90/10 (PPS/HDPE). In summary it is concluded that blending of HDPE with PPS influences the crystal growth of PPS significantly although the effect on its homogeneous nucleation is also considerable. As a result, the morphology of PPS crystallized in blends is different from that of the homopolymer. The changes in the morphology of PPS are not sensitive to the molecular weight of HDPE probably because of the high temperature of PPS crystallization relative to the melting point of HDPE.

Heat Transfer Modeling of Oriented Sorghum Fibers Reinforced High-Density Polyethylene Film Composites during Hot-Pressing.

A one-dimensional heat transfer model was developed to simulate the heat transfer of oriented natural fiber reinforced thermoplastic composites during hot-pressing and provide guidance for determining appropriate hot-pressing parameters. The apparent heat capacity of thermoplastics due to the heat of fusion was included in the model, and the model was experimentally verified by monitoring the internal temperature during the hot-pressing process of oriented sorghum fiber reinforced high-density polyethylene (HDPE) film composites (OFPCs). The results showed that the apparent heat capacity of HDPE accurately described its heat fusion of melting and simplified the governing energy equations. The data predicted by the model were consistent with the experimental data. The thermal conduction efficiency increased with the mat density and HDPE content during hot-pressing, and a higher mat density resulted in a higher mat core temperature. The addition of HDPE delayed heat transfer, and the mat had a lower core temperature at a higher HDPE content after reaching the melting temperature of HDPE. Both the experimental and simulated data suggested that a higher temperature and/or a longer duration during the hot-pressing process should be used to fabricate OFPC as the HDPE content increases.

Compressive mechanical properties of cement mortar containing recycled high-density polyethylene aggregates: Stress–strain relationship

This study contributes to the understanding of the effect of recycled high-density polyethylene (HDPE) aggregates on the compressive mechanical properties and stress–strain relationship of cement mortar. HDPE aggregates recycled from plastic wastes were used to substitute natural sand in cement mortar, thereby offering a novel approach to plastic waste management and reducing the overconsumption of limited natural resources. The compressive behavior of cement mortar containing 0–100% HDPE contents was investigated after 7 and 28 days. The experimental results showed the negative effect of HDPE aggregates on the modulus of elasticity (Ec) and compressive strength (fcmax) of cement mortar. However, the substitution of natural sand with HDPE aggregates reduced the density and increased the axial deformation capability of cement mortar, particularly when the volumetric substitution percentage exceeded 50%. The Ec, peak strain, and ultimate strain exhibited strong relationships with the substitution percentage and fcmax. Furthermore, the proposed empirical relationships between the parameters were evaluated. Finally, stress–strain models of HDPE mortars were established based on the available models for concrete. The proposed models appropriately predicted the complete stress–strain curves of cement mortars containing various amounts of plastic content.

Investigation of Biochar Production from Copyrolysis of Rice Husk and Plastic.

Biomass renewable energy has become a major target of the Thailand Alternative Energy Development Plan (AEDP) since the country’s economy is largely based on agricultural production. Rice husk (RH) is one of the most common agricultural residues in Thailand. This research aims to investigate yields and properties of biochar produced from copyrolysis of RH and plastic (high-density polyethylene (HDPE)) at different ratios, temperatures, and holding times. For both individual and copyrolysis, the temperature variation generated more pronounced effects than the holding time variation on both biochar yields and properties. For individual pyrolysis of RH, the maximum biochar yield of ∼54 wt % was obtained at 400 °C. A shift in temperature from 400 to 600 °C resulted in RH biochars with higher fixed carbon (FC) and carbon (C) contents by ∼1.11–1.28 and 1.06–1.22 times, respectively, while undetectable changes in higher heating values (HHVs) were noticed. For copyrolysis, obvious negative synergistic effects were observed due to the radical interaction between the rich H content of HDPE and RH biochars, which resulted in lower biochar yields as compared to the theoretical estimation based on individual pyrolysis values. However, the addition of HDPE positively impacted the FC and C contents, especially when 10 and 20 wt % HDPE were added to the feedstock. Besides, higher HDPE blending ratios resulted in biochars with improved HHVs, and >1.5 times improvement in HHV was reported in the biochar with 50 wt % HDPE addition in comparison with RH biochar obtained under the same conditions. In summary, biochars generated in this study have the potential to be utilized as a solid fuel or soil amendment.

Development of sustainable concrete using recycled high-density polyethylene and crumb tires: Mechanical and thermal properties

Recycling the non-biodegradable waste materials in concrete is becoming necessary to reduce the environmental pollution in industrial and urbanization countries. Further, since energy-saving is a critical issue worldwide, particularly in hot climate conditions, minimizing the heat flow from the outside to inside the building roofs is also the demand of both the residents and authorities as reflected by the building's codes. In this regard, experimental work was conducted to investigate the concrete's mechanical and thermal properties. Two replacement materials, namely crumb rubber (Ru) and high-density polyethylene (HDPE), were used to replace fine and coarse aggregates to produce insulation concrete. Further, the cost analysis, oil fuel consumption, CO2, and SO2 emissions were computed as a function of the thermal resistance that was figured out from experimental work. The experimental results of insulation concrete revealed that the thermal conductivity was reduced by about 40%, with little lower values for rubber as related to polyethylene. Likewise, it was found that the use of Ru and HDPE with a maximum dosage of 50% resulted in reducing the strength of normal concrete with a maximum value of 90% and 82% for Ru and HDPE, respectively. The flexural strength decreased with increasing Ru and HDPE's content by about 50%. In contrast, the use of Ru and HDPE in the concrete enhanced the ductility performance. Results suggest the usage of screed concrete with 50% of Ru and HDPE replacements to achieve maximum thermal resistance. It is found that the best mixtures (Ru-50% and HDPE-50%) enhance the thermal resistance by about 59 and 48% as compared to the control normal concrete mixture. Based on net present value (NPV) over 30 years, the thermal resistance improvement could decrease the cost of energy consumption from 596 to 377.2 and 405.1 $/m2 for concrete with Ru-50% and concrete with HDPE-50%, respectively. Furthermore, these two optimal mixes could also minimize the oil fuel consumption, CO2 and SO2 emissions from 75.14, 243 and 1.26 (kg/m2.year) to 47.34, 152 and 0.79 (kg/m2.year) when Ru-50% of coarse replacement is used and 50.92, 164 and 0.85 (kg/m2.year) when using HDPE-50% with coarse aggregate replacement, respectively.

Properties of Mortar Composites from Plastic Waste

ABSTRACT An application of plastic waste blended with the sand aggregate in mortar helps to improve some properties of the mortar as well as reducing environmental pollution while solving the problem of a shortage of natural sand. In this study, polystyrene (PS) and high density polyethylene (HDPE) wastes were examined as partial replacements for sand in mortar. The water absorption, bulk dry density, flow value and compressive strength of mortar containing these plastic wastes were analyzed. In addition, the thermal conductivity of wall models plastered with mortar containing plastic waste was investigated. The main results were as follows. The plastic waste and the sand had comparable particle sizes. The properties of mortar with PS were found to be better than that of the mortar with HDPE. The water absorption of mortar with PS was comparable with the reference mortar but lower than that of mortar with HDPE. The compressive strength of the mortar with PS was significantly higher than that with HDPE. The thermal conductivity of a wall plastered by mortar containing PS decreased as the PS content was increased, whereas the thermal conductivity of a wall plastered by mortar containing HDPE increased as the HDPE content was increased. The results indicated that 10.0% PS could be used as a partial replacement for sand in mortar with an improvement in some of the properties of the mortar.

RESISTIVITY AGAINST SULFATE ATTACK OF CONCRETEWITH HDPE AS PARTIAL SUBSTITUTE FOR FINE AGGREGATES

High-Density Polyethylene (HDPE) when used as partial substitute of fine aggregates in concrete is investigated to determine if it addresses sulfate attack in concrete. Since HDPE is known to be resistant against chemical compounds including sodium sulfate, it is hypothesized in this study that sulfate attack problems in concrete will be lessened by incorporating HDPE in concrete mix. Mechanical properties of concrete were determined to ensure that HDPE is limited to an amount where there will be no serious compromise to strength, hence, compressive, and split tensile test are included in the study. To determine the influence of HDPE in addressing sulfate attacks, length change of mortar specimen is investigated using ASTM C1012 (length change of mortar exposed to sulfate solution). Scanning Electron Microscopy (SEM) is also employed to qualitatively assess the microstructure of concrete with HDPE exposed to sulfate attacks. Mechanical test results showed that increasing HDPE did not adversely affect the compressive strength. However, there was a decrease observed in tensile strength. To achieve balance between mechanical properties, HDPE replacement of fine aggregates was set at 10% by weight of fine aggregates. The mortar bar test demonstrated that increasing HDPE resulted to an increased resistivity against sulfate attacks. SEM have also shown reduction in voids and ettringite with increasing HDPE content

Assessment of Marine Debris and Plastic Polymer Types Along the Panvel Creek, Navi Mumbai, West Coast of India

Marine debris was collected monthly from substations along Panvel creek from May 2020 to April 2021 and was analyzed for types of non-plastic debris and plastic debris. Plastic debris was assessed for % composition of a type of plastic, plastic polymer and further categorized according to plastic code, acronym, full name and common examples. Non-plastic debris of 8 types representing 38 items were recorded. Consumer and manufactured items like glass and plastic bottles, cans, bags, rubber, metal, fiberglass, cigarettes, fishing gears etc. were observed. 8 types of polymers representing 65 items were recorded along Panvel creek. Plastic polymers like Polyethylene terephthalate (PETE/PET), High density polyethylene (HDPE), Polyvinyl chloride (PVC), Low density polyethylene (LDPE), Polypropylene (PE), Polystyrene (PS), Polyamide/Nylon, Acrylonitrile Butadiene Styrene (ABS) and Polyurethane (PU) were recorded. 13 items belongs to Plastic code 2:HDPE, 12 to 3:PVC, 11 to 5:PP, 9 to 6:PS, 8 to 4:LDPE, 6 to 1:PETE/PET and 3 each to 7:PA and Other and 8:PU, respectively, were documented. Maximum % composition (20.00%) of HDPE, and minimum (4.61%) of PA and Other and PU, respectively was recorded. Higher content of debris recorded is attributed to the disposal of domestic wastes intentionally or unintentionally into the creek and also for disposal of scrap materials from the fishing crafts. Higher HDPE content is attributed to the wastes released from the fishing vessels and also to the domestic and municipal wastes. At present the Panvel creek is moderately polluted and 3R i.e. reduce, reuse and recycling is the current solution to the overuse of plastics.

Linear low‐density polyethylene/high‐density polyethylene blends: Effect of high‐density polyethylene content on die swell and flow instability

AbstractThis work aimed to evaluate the effect of high‐density polyethylene (HDPE) content and of shear rate on the die swell and flow instability of linear low‐density polyethylene (LLDPE)/HDPE blends. The results showed that the die swell of the LLDPE/HDPE blends increased with the increase in the shear rate. At high shear rates, the increase in the HDPE content led to an increase in the die swell of LLDPE/HDPE blends. The surface morphology analysis of the extrudates by optical and scanning electron microscopy revealed the presence of sharkskin and stick–slip flow instabilities in LLDPE and LLDPE/HDPE blends at the shear rates investigated. These instabilities were attenuated with the addition of HDPE and almost disappeared in the LLDPE/HDPE blend containing 50 wt% of HDPE.