High-density Polyethylene Plastic Research Articles

Microbes Breaking Down Plastic: Insights for Sustainable Waste Management

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.

Study on the behavior of pulling power and flammability of mold walls mixed with high-density polyethylene plastic waste

Currently, materials used in construction have been continuously developed in terms of quality and efficiency, especially fiber reinforcement in mortar, a form of development used in construction. The development aims to enhance concrete's tensile properties and performance for higher flexibility. Most plaster walls are ordinary mortar and have low elasticity, which is a weak point. Therefore, attempts are being made to improve their properties by using a rigid material as a concrete mixture, namely high-density polyethylene plastic, to increase its ability to bear tensile force. This study examines the tensile strength and flammability tests of walls plastered with mortar, with which high-density polyethylene plastic waste is mixed. The tensile strength of mortar plaster walls mixed with high-density polyethylene plastic is tested by replacing at 2.5%, 5%, and 10% proportions and cured at 7, 14, and 28 days. By comparing general mortar and high-density polyethylene plastic mortar, it is found that the general mortar had the highest tensile strength at 28 days of curing. The obtained value is 45 ksc, and the mortar mixed with polyethylene plastic in the amount of 2.5% at 28 days of curing can withstand the strength of 45 ksc. In addition, the general mortar can produce the same tensile strength as mortar mixed with high-density polyethylene plastic. The flammability test shows that general mortar develops red marks after being burned with fire, while the mortar combined with high-density polyethylene plastic develops black marks. However, neither type of wall is in flames nor spread.

Impact of Packaging Materials on the Shelf Life of Enriched Aadun (Maize Meal Snack commonly consumed by the Southwestern region of Nigeria)

Optimum condition at 64.80% maize flour, 20% groundnut paste and 13.20 % palm oil was formulated to produced nutritionally enhanced aadun snack. The snack was stored in the different storage materials namely, sweet prayer plant leaves (control) which is usually used by most locals, low density polyethylene (LDPE), high density polyethylene (HDPE) and food grade plastic container (PC). The initial properties (energy, oxidative and sensory properties) of the enhanced aadun (before storage) were investigated and stored in each of the storage materials. The enhanced aadun samples in each storage material were analysed at two weeks interval for eighteen weeks. The results obtained were analysed statistically to examine the effect of the storage material on the aforementioned properties. The results for energy content decreased significantly (P>0.05) in across all the samples stored. The free fatty acid, acid valve and peroxide value increased significantly (P<0.05) in all the storage materials during the storage period but only the samples stored in PC and HDPE were within the recommended limit of FAO (Food and Agricultural Organization) at the end of the storage period. The sensory quality of the control sample was acceptable up to 12 weeks while samples in other storage materials were still acceptable at the end of the storage period under ambient storage condition.

Combined effect of silica fume and various fibers on fresh and hardened properties of concrete incorporating HDPE aggregates

Recycling of waste plastics has become essential to mitigate their detrimental impact on the environment. However, it can be used in the construction sector to fulfill construction needs and conserve natural resources. Previous research has demonstrated that incorporating plastic aggregate reduces the strength properties of concrete; hence, there is a need to improve its strength properties. In this study, high-density polyethylene (HDPE) plastic is incorporated in aggregate form, as a partial substitute for natural coarse aggregates (NCA) at volumetric ratios of 10 %, 30 %, and 50 %. Various strength enhancement techniques, including the addition of macro synthetic fibers (MSF), steel fibers (SF), and substituting 20 % of cement with silica fume, were employed. The results indicated that workability of concrete is improved with an increase in the content of HDPE coarse aggregates (HCA). Furthermore, concrete containing 30 % HCA performed better in terms of strength compared to concrete with 10 % and 50 % HCA. The findings demonstrate that concrete containing fibers performs better than concrete without fibers. The utilization of 0.75 % MSF and 1 % SF dosage leads to a 93 % improvement in splitting tensile strength, a 72 % improvement in flexural strength, and a 48 % improvement in compressive strength for concrete containing 30 % HCA. Using scanning electron microscopy, it was found that incorporating HCA weakens the internal matrix. However, the addition of a precise amount of fibers and pozzolanic materials resulted in improvements in microstructure. The significance of this research lies in the utilization of HDPE waste materials in concrete by simultaneous usage of different fibers.

Investigation on the mechanical properties of wood-plastic composites for the application of ceiling panels

Wood-plastic composites are relatively novel composite materials that consist of a blend of wood flour waste with high-density polyethylene and polypropylene plastic waste, designed for use in ceiling applications. Various samples were produced using different ratios from the total weight, including 20:80, 30:70, and 40:60, with sieve sizes of 0.425 mm, 1.18 mm, and 2 mm. The composites were created by melting plastics and sawdust at a temperature of 1800c utilizing the hot-press moldings technique employing diverse formulations. The properties of sample composites were analyzed experimentally based on ASTM standards to investigate water absorption levels as well as flexural strength, impact resistance hardness along with surface morphology via the design of experiments. This research study indicates that nine composite formulations consisting of HDPE and PP plastics combined with wood flour can produce favorable physio-mechanical properties. Among these various combination specimens tested in this study FS3/FC30N exhibited excellent physio-mechanical properties; including desirable values such as water absorption level at 5.5103%, flexural strength at 61.12 Mpa, impact resistance measuring 33.45 J cm−2, and hardness rating up to 80 RHB. Thus it is highly recommended for use in chipboard ceiling panel applications due to its potential benefits.

Revitalizing high-density polyethylene (HDPE) waste: from environmental collection to high-strength hybrid yarns

AbstractPlastic products are used in large quantities. However, the fact that plastics do not degrade in nature for many years causes environmental pollution. Addressing this issue, the study focuses on recycling the widespread high-density polyethylene (HDPE) plastic waste. In this study, HDPE waste was collected randomly from the environment, mirroring real-world scenarios. Then, the waste was transformed into granules. Afterward, washing and drying processes were carried out. HDPE filaments of different linear densities were successfully produced from the waste plastic granules. Tensile tests revealed that the breaking strength of the filaments from waste plastic was lower than that of virgin HDPE filaments, highlighting the challenges of recycling. Hybrid yarns were formed by twisting the filaments with cotton yarn to improve the mechanical properties of the filaments from waste plastic. Remarkably, statistical analysis demonstrated that the breaking load values of the hybrid yarns from waste plastic were statistically equivalent to those made from virgin polymer. This outcome indicated that the hybrid yarns made from waste HDPE plastic were as strong as those made from virgin HDPE polymer. In addition, both hybrid yarns exhibited a breaking load 36% higher than the reference extra-twisted cotton yarn. The hybrid yarn formation made filaments produced from waste plastic a valuable component of the high-strength hybrid yarn. Overall, this study shows that recycling HDPE plastics can lead to the production of high-strength hybrid yarns, which can contribute to reducing plastic waste pollution.

Design and Construction of an Anaerobic Digester for the Ingestion of Waste from the Cocoa Industry in Nigeria

The Anaerobic Digester designed and constructed for waste ingestion from the Nigerian cocoa industry aims to harness abundant renewable energy from crop residues like cocoa rinds and groundnuts. This study evaluates the biogas potential of these sources in contributing to the country's overall energy needs, emphasizing the imperative for environmental sustainability. Focusing on reducing fossil energy consumption, greenhouse gas emissions, and minimizing environmental impact, the project advocates for a shift towards biogas for day-to-day energy requirements, presenting direct cost savings. The utilization of fossil fuel-derived energy is known to contribute to temperature increase, greenhouse gas emissions, noise pollution, and ground-level air pollution, all of which can be mitigated through biogas utilization. This initiative involves the design and construction of a 0.24m<sup>3</sup> pilot plastic fossil plant for biogas generation, aiming to "green" various applications, including domestic and industrial usage as well as transportation. The digester, constructed from high-density polyethylene (HDPE) plastic, demonstrates leak-free operation, further supporting its potential for long-term sustainability. Results from a 28-day retention period show a cumulative biogas yield, with a daily assessment indicating a gas yield of 0.0496 m<sup>3</sup> on the 12th day. The study highlights the positive and negative influences of temperature inequality gradients ≥34°C≤38°C on biogas production. This comprehensive research contributes valuable insights for the sustainable management of waste and the utilization of biogas as a viable alternative energy source.

Studies on partial replacement of waste high density polyethylene (HDPE) and polypropylene (PP) plastic with fine aggregate (FA) on mechanical, durability and thermal properties of M30 and M40 grade concrete

The aim of the present paper is to incorporate two different waste plastic materials that is High-Density Polyethylene (HDPE) and Poly-Propylene (PP), were replaced with Fine Aggregate (FA) at a 10% by 2.5% increment. The widespread formation of HDPE and PP waste plastics has become a major environmental issue, endangering ecosystems and human health. Traditional disposal techniques, such as landfills and incineration, lead to pollution and resource depletion. Incorporating these polymers into concrete provides a long-term solution that reduces environmental effect while improving material qualities. The Different tests conducted are compressive strength (3, 7, 28 and 60 days) (150 × 150x150 mm), flexural strength (3, 7, 28 and 60 days) (100 × 100x500 mm), acid attack (28, 56 and 90 days) (100 × 100x100 mm), sulphate attack (28, 56 and 90 days) (100 × 100x100 mm), and thermal conductivity (180 mm dia x 20 mm thick). The compressive strengths of 40.52 MPa and 38.41 MPa for PP and HDPE material were observed in M30-grade concrete, respectively. Similarly, for M40-grade concrete, 43.6 MPa and 41.8 MPa are for PP and HDPE material, respectively. The optimum percentages of 5% and 7.5 for PP and HDPE material, respectively, can be replaced in concrete for flexural strength in both M30 and M40 grades. The least percentage loss in acid attack was observed at 28 days for both HDPE and PP material, but for 56 days and 90 days, the percentage loss of weight was significantly less (< 5%). The sulphate attack for both M30 and M40 grade concrete showed less than 10% percentage loss in weight after 90 days. Thermal conductivity (k) was also reduced by 30–35% for both HDPE and PP material, with 10% replacement in concrete for M30 and M40 grades. The use of Waste HDPE and PP material can be used to improve the mechanical, durability & thermal property of M30 and M40 grade concrete under controlled conditions.

The Effect of Recycled High-Density Polyethylene (HDPE) as an Additional Binder in Porous Asphalt Pavement

Porous asphalt has excellent permeability and larger air voids. Due to the low stability strength of asphalt binder with aggregates, Malaysia uses porous asphalt roads for lightweight vehicle road transportation. Numerous studies indicate utilizing Recycled High-Density Polyethylene in porous asphalt road surface. As a result, it was utilised as an additional binder material to enhance the asphalt binder. The main purpose of this study is to investigate the stability of modified porous asphalt samples and evaluate the optimum percentage of HDPE plastic waste from 3%, 6% and 9%. The aggregates, asphalt properties, Marshall Parameters and waster absorption test are in comply with JKR Standard and PWD 2008. At 3% of plastic addition has improved the stability of porous asphalt specimens. Adding plastic waste as a binder helps strengthen asphalt binding.

Boosting the efficient combustion of plastic wastes via tailoring the oxygen vacancies of Ce-Zr solid solution

Novel-design catalyst is a promising candidate for the clean combustion of plastic wastes, alleviating the environmental and energy crisis. Herein, Ce-Zr catalysts with different oxygen vacancies were prepared by tailoring the Zr-content to optimize the catalytic performance in plastic wastes combustion. The detailed characterization results confirmed that Zr has been successfully incorporated into CeO2 lattice, which decreased the crystal size and increased the surface area. Moreover, the Zr-doping caused the lattice distortion, i.e., Ce-O around the doped Zr was elongated to compensate the shortness of Zr-O, which made it easy to break and generate oxygen vacancies. DFT calculation results revealed that Ce0.8Zr0.2O2 exhibited a lower energy of oxygen vacancies formation (2.22 eV) and O2 adsorption (−1.20 eV) than that of CeO2 (2.46 eV and −0.42 eV). It indicated that the Zr-doping improved the oxygen vacancies and O2 adsorption of Ce-Zr catalysts. Ce0.8Zr0.2O2 significantly improved plastic wastes combustion at 250 °C, and achieved a conversion of 14.3 %, 21.8 %, 100 %, 22.4 % and 13.7 % for high-density polyethylene, low-density polyethylene, polypropylene, polystyrene and real plastic wastes, which was 2–3 times that of the non-catalytic combustion. This has been attributed to the superiority of Ce0.8Zr0.2O2 in the crystal and texture structure as well as the oxygen vacancies and O2 adsorption, i.e., the improved external surface enhanced the contact with polymer molecules, and the improved oxygen vacancies as well as O2 adsorption provided more active oxygen.

ANALISIS PENGARUH SUHU PEMANASAN, WAKTU PEMANASAN DAN SUHU PEMBUKAAN TERHADAP CACAT WARPAGE DAN FLASHING PADA MESIN HOT PRESS PLASTIK HDPE

The current issue of plastic waste has not yet received appropriate handling, resulting in the inadequate control of plastic waste management practices. Particularly, High Density Polyethylene (HDPE) is still widely encountered. HDPE is a thermoplastic made from petroleum with a melting temperature of 160ºC-240ºC, characterized by being slightly cloudy, transparent, and elastic. This research will conduct testing using a complete randomized design (RAL) factorial analysis with 3 factors to determine the influence of factor A (heating temperature), the influence of factor B (heating time), and the influence of factor C (opening temperature) on flashing defects and warpage defects in HDPE plastic. Based on the testing of flashing defects, the significant influencing factors are factor A (heating temperature), factor B (heating time), factor C (opening temperature), and the interaction of factors AB (heating temperature and heating time). Meanwhile, the significant influencing factors on warpage defects are factor A (heating temperature), factor B (heating time), and the interaction of AB (heating temperature and heating time). Based on this research, the characteristics of HDPE plastic can be determined.

RANCANG BANGUN MESIN HOT PRESS LIMBAH PELASTIK SERTA PERHITUNGAN KONSUMSI ENERGI PENCETAKAN

The issue of waste, particularly plastic waste, remains a challenging problem without a definitive solution. Plastic waste, especially that made from High-Density Polyethylene (HDPE), takes an extensive amount of time to decompose. Currently, plastic recycling machines are priced in the hundreds of millions, making them less accessible. Therefore, there is a need for affordable machines that function effectively alongside existing ones. This research introduces a hot press machine for recycling HDPE plastic. The hot press machine is capable of recycling HDPE plastic waste and offers the advantages of being portable, compact in size, and cost-effective. Following the design phase, the machine is capable of producing plastic boards with a thickness of 1 cm, utilizing 3.7 kg of plastic, and requiring a molding time of 2 hours and 15 minutes at a pressure of 4.36 MPa.Subsequent testing involved analyzing three factors to determine the significant influence of factor A (heating temperature) and factor B (heating time) on energy consumption. The goal was to identify the interaction that yielded the smallest average energy consumption.

Comparison of Antioxidants to Increase the Oxidation Stability of Pyrolysis Oils of Three Plastics Using Iodine Value

Pyrolysis is an excellent method for recovering mixed and contaminated plastics that are no longer recyclable. Special attention must be paid to the stability of the fuel to avoid the formation of undesirable products. This can be achieved by additives such as antioxidants. In this study, high-density polyethylene, polypropylene, and polystyrene plastic waste are slowly pyrolyzed to a maximum of 470 degrees Celsius. A gasoline fraction (0–190 °C) and a diesel fraction (190–320 °C) are then obtained from these. Three antioxidants are added to these fractions: pyrocatechol, phenol, and freshly produced algal pyrolysis oil; the latter is described in the literature as containing particularly high levels of antioxidants. The oxidation stability of these mixtures and the change in the iodine number over time are measured using a newer method than the commonly used method of Wijs. Phenol improves the oxidation stability best, followed successively by algae pyrolysis oil and pyrocatechol. The oxidation stability of the gasoline fraction of the polypropylene pyrolysis oil with phenol is 49% higher than that of the same fraction without antioxidants.

Integrating aerosol emissions of forest biomass into a life cycle assessment of forest-based production

Climate change mitigation is globally increasing the demand for forest biomass to substitute for fossil-based materials. Consequently, fossil-based greenhouse gas emissions will decrease, but simultaneously, aerosol emissions may substantially change. The evaluation of the substitution effects of forest-based materials may be biased if aerosol emissions are not considered. We integrated aerosol emissions from the use of forest-based biomass and fossil-based materials into a life cycle assessment (LCA) tool and simulated the biomass production of Norway spruce under alternative harvest intensities of energy biomass in middle boreal conditions in Finland. For the forest management regimes, we calculated particulate matter (PM) emissions; i.e. total suspended particles (TSP), respirable particulate matter (PM10), fine particulate matter (PM2.5) and black carbon (BC), and gaseous emissions including nitrogen oxides (NOx), sulphur dioxide (SO2) and non-methane volatile organic compounds (NMVOC). We also considered how replacing fossil counterparts and peat with forest-based biomass energy affects aerosol emissions. The differences between the management regimes were minor for sawn logs and pulpwood. Energy biomass use, especially combustion in small-scale appliances, increased aerosol emissions. Energy biomass use produced higher PM (TSP, PM10, PM2.5, BC) emissions than the use of coal and peat as energy. Regarding construction materials, the highest aerosol emissions were found for sawn wood production, followed by steel production. Cardboard production emitted remarkably higher aerosol emissions than high-density polyethylene (HDPE) plastic production. The inclusion of aerosol emissions of forest biomass use seems to be important for assessing the climate and health effects of the transition to a forest bioeconomy.

Optimization of value-added products using response surface methodology from the HDPE waste plastic by thermal cracking

The current research aims at the thermal degradation of waste plastic in the presence of bentonite solid catalyst to produce value added products such as fuel oil, gas and charcoal. The thermal cracking of High-Density Polyethylene plastic produces the liquid fuel with conversion around 84.46 % with the characteristics: heating value 35.5 MJ/Kg, density 0.749 g/cc, viscosity 1.43cSt, a boiling point 200 °C and flash point 16 °C. The response surface methodology using the central composite design (CCD) method have been investigated to evaluate the effect of independent variables such as heating rate, temperature, time of operation on the production of value-added products. The optimal operating values for temperature, heating rate and batch time are 473.74 K, 24.9 °C/min and 159.90 min respectively. At the optimal operating conditions, the value-added products produced are fuel oil 91.16 %, gaseous products 8 % and solids 2 %. The experimental results were best fitted with quadratic polynomial model with the appreciable regression coefficient using the response surface method of analysis.

Design a machine with technology to convert plastic waste into fuel renewable energy

Research has been carried out on the design of machines with technology to convert plastic waste into fuel renewable energy, the aim is to find out pyrolysis technology which is a technology in converting plastic waste into reusable gas and liquid phases that have the potential to be used as renewable energy. The machine consists of one pyrolysis reactor, 3 condensers, 3 storage tanks. The standard method used to test samples is ASTM D4052. This plastic waste converter machine uses Polypropylene and High-Density Polyethylene plastics. The results showed that the most pyrolysis oil from PP plastic waste was 0.52 kg and HDPE was obtained as much as 0.62 kg from each type of waste material as much as 3 kg. For PP plastic waste, the specific gravity of oil is 866.7 kg/m3 and 743.1 kg/m3 and HDPE plastic the specific gravity of oil is 842 kg/m3 and 737.7 kg/m3. The specific gravity of pyrolysis oil in waste PP plastic and HDPE plastic is close to the specific gravity of diesel fuel and gasoline. Data based on Directorate General of Oil and Gas Indonesia for specifications of diesel specific gravity 815-870 kg /m3, specifications of gasoline type 88 is 715-770 kg /m3.

Composite materials using recycled high-density polyethylene plastic for railway sleepers

Given the substantial increase in railway load, speed and traffic, there is a notable demand for materials with high durability, long life and good damping. Such materials can be realized through composite materials that contain recycled high-density polyethylene, polypropylene (PP), mica, glass fiber and compatibilizers. In this study, extruded pellets containing the aforementioned materials and produced using a twin-screw extruder were utilized to assess their mechanical performances and microstructures. Composite materials containing 62.5% glass fiber and 20% PP demonstrated remarkable performance for manufacturing sleepers. The addition of 62.5% glass fiber in composite materials containing PP enhanced the flexural strength, flexural modulus, tensile strength and compressive strength by 315, 623, 296 and 40%, respectively, as compared with those of the original composite materials containing PP without glass fiber. Furthermore, the incorporation of glass fiber and the subsequent improvements met the requirements stipulated by the Ministry of Housing and Urban–Rural Development of the People’s Republic of China and International Organization for Standardization standards. This favorable result can be attributed to the good compatibility between the matrix and the glass fiber, as noted from the uniform distribution of glass fiber in the resin matrix in scanning electron microscopy images. The findings of this study highlight the potential of utilizing recycled materials in rail-track-manufacturing applications.

Waste management of household-scale snack industry based on Reduce, Reuse, Recycle (3R) In Watubonang Ponorogo

The household food industry that produces fish-based snacks in Ponorogo needs good waste management. Therefore, the waste is directly disposed of into the irrigation channel and vacant land. The waste produced by the industry contains highly organic compounds, which results in several problems, such as foul odor and eutrophication due to excess nitrogen and phosphorus. The management of water and solid wastes is a must to prevent environmental pollution, reduce waste circulation, and create better production; one of the methods that can be used is Reduce, Reuse, and Recycle (3R). Primary data were collected by sampling, laboratory analysis, and field research. In contrast, the secondary data were collected through literature studies. Based on the analysis results, reduction is done on liquid waste, compostable, and non-recyclable solid waste. Reuse is done on liquid waste and recyclable solid waste. Recycle is done on compostable and recyclable solid waste. Based on waste management, the treatment units begin with a grease, then an equalization basin, an Anaerobic Baffled Reactor (ABR), and constructed wetland. Solid waste storage for all types uses closed High Density Polyethylene (HDPE) tubs. Composting is carried out on compostable solid waste aerobically in a HDPE plastic tub.

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.

Tensile and Flexural Properties of Recycled HDPE for Application in Building Products

Plastic waste generation is a major environmental threat with farreaching consequences that needs to be dealt with. High density polyethylene (HDPE) is a common plastic waste coming out of daily household products. Recycling of HDPE plastic waste has been a viable alternate to disposal. To the best of author’s knowledge, no work has been reported on the material properties of recycled HDPE in perspective of building products. This study investigates the tensile and flexural properties of mechanically recycled HDPE for potential application in building products. The specimen’s behaviour under loading has also been reported. Based on the findings, 2.5% elongation at fracture was observed having 14.25 MPa strength against tension. Whereas, 32.6 MPa modulus of rupture was obtained with toughness index of 1.45 against flexure. In addition, potential application of recycled HDPE for manufacturing building products has been discussed keeping in line the material properties of recycled plastic. The adoption of recycled waste material instead of conventional materials can significantly influence the construction industry positively.