Polyethylene PE Research Articles

Environmental and economic assessment of mixed plastic waste pelletization in the Gulf Cooperation Council region

Pelletizing mixed plastic wastes (MPW) has gained interest as an upcycling technology and an alternative to conventional recycling. To investigate its potential, we conducted a cost analysis and life-cycle assessment (LCA) for a conceptual pelletization facility designed to produce 1 kg of pellets per batch of MPW (comprising polyethylene—PE and polypropylene—PP). This work has the following merits: (i) evaluating environmental impact (EI), cost analysis, and mechanical strength based on actual experimental data and its comparison with local and international manufacturers; (ii) enabling the evaluation of LCA impacts of MPW pellets; and (iii) emphasizing the significance of waste management in reducing EIs. The following ten EIs were assessed: climate change (CC), net energy, particulate matter formation, natural land transformation, metal depletion, marine ecotoxicity, ionising radiation, freshwater ecotoxicity, freshwater eutrophication, and terrestrial ecotoxicity. The CC of the as-synthesized pellets is 1.26 kg CO2 eq., significantly lower than the data obtained from the Gulf Petrochemicals and Chemicals Association (GPCA) and an actual plant in Gulf Cooperation Council (GCC) countries. Additionally, the net energy required for the production of 1 kg of pellets is 54.1 MJ, while the cost is around 0.55 USD. The tensile strength of MPW pellets (24.63 MPa) falls between that of PE virgin pellets (21.12 MPa) and PP virgin pellets (28.12 MPa). This suggests that the MPW pellets exhibit competitive strength characteristics, warranting its consideration for applications where moderate strength is required. Overall, the competitive cost, coupled with the reduced EIs, demonstrates the potential of pelletization as a sustainable and economically viable waste management solution.

Plasma treatment process for accelerating the disintegration of a biodegradable mulch film in soil and compost

Biodegradable Mulch Films (BMFs) offer a sustainable alternative to traditional non-degradable (Polyethylene) PE mulch films. However, their slow rate of biodegradation can lead to plastics accumulation in soil. In this study, a commercially available BMF based on poly (butylene adipate co-terephthalate) (PBAT) and poly (lactic acid) (PLA) is examined. Here the effects of gliding arc plasma treatment on the bulk and surface properties, as well as its degradation behavior in soil and compost is studied. An increase in surface oxygen containing species and hydrophilicity was observed following plasma treatment. Only a small hydrophobic recovery was noted over 30 days. No changes in the bulk polymer molecular weight or thermal properties following treatment were noted. However, a decrease in mechanical strength was observed following gliding arc plasma treatment. The onset of film fragmentation in both soil and compost occurred earlier for a plasma treated film and we attribute this to an improvement in the initial adhesion of bacteria on the surface.

Five-year polyethylene cup migration and PE wear of the Anatomic Dual Mobility acetabular construct.

Dual mobility implants have been successful in reducing postoperative hip dislocation but mid-term results of cup migration and polyethylene wear are missing in the literature. Therefore, we measured migration and wear at 5-year follow-up using radiostereometric analysis (RSA). A cohort of 44 patients (mean age 73, 36 female) with heterogeneous indications for hip arthroplasty but all with a high risk of hip dislocation received total hip replacement (THA) with The Anatomic Dual Mobility X3 monoblock acetabular construct and a highly crosslinked polyethylene liner. RSA images and Oxford Hip Scores were obtained perioperatively and 1, 2, and 5years postoperatively. Cup migration and polyethylene wear were calculated using RSA. Mean 2-year proximal cup translation was 0.26mm (95% CI 0.17; 0.36). Proximal cup translation was stable from 1- to 5-year follow-up. Mean 2-year cup inclination (z-rotation) was 0.23° (95% CI - 0.22; 0.68) and was greater in patients with osteoporosis compared to patients without osteoporosis (p = 0.04). Using 1-year follow-up as baseline, the 3D polyethylene wear rate was 0.07mm/year (0.05; 0.10). Oxford hip scores improved 19 (95% CI 14; 24) points from mean 21 (range 4; 39) at baseline, to 40 (9; 48) 2years postoperatively. There were no progressive radiolucent lines > 1mm. There was 1 revision for offset correction. Anatomic Dual Mobility monoblock cups were well-fixed, the polyethylene wear rate was low, and the clinical outcomes were good until 5-year follow-up suggesting good implant survival in patients of different age groups and with heterogeneous indications for THA.

Application of the Small Punch Creep-Recovery Test (SPCRT) for the Estimation of Large-Amplitude Viscoelastic Properties of Polymers.

The Small Punch Creep-Recovery Test (SPCRT) is a novel miniature test used to estimate the viscoelastic properties of polymers and biomaterials. The current investigation related to the SPCRT is limited to Finite Element Method (FEM) simulations and experimental tests on PVC. The aim of this investigation was focused on: (i) extending the experimental tests to other polymers with dissimilar viscoelastic properties; (ii) deepening the influence of non-linear viscoelastic properties in the estimation capabilities of the SPCRT; and (iii) developing a numerical methodology to estimate and take into account the viscoelastic recovery produced during the unloading step of compressive creep-recovery tests (CCRT) and SPCRTs. The experimental tests (CCRTs and SPCRTs) were done on polyethylene PE 500, polyoxymethylene POM C, nylon PA 6, and polytetrafluoroethylene (PTFE), with a range of creep loads, in the case of CCRTs, in the whole elastic regime and the surroundings of the yield strength of each material. The experimental results confirmed that the SPCRT was an accurate and reliable testing method for linear viscoelastic polymers. For a non-linear viscoelastic behavior, SPCRT estimated the viscoelastic properties obtained from CCRTs for creep loads near the yield strength of the polymer, which corresponded with large-amplitude viscoelastic properties in dynamic creep testing. In order to consider the viscoelastic recovery generated in the unloading step of CCRTs and SPCRTs, a Maxwell-Wiechert model with two branches was used, simulating the different steps of the experimental tests, and solving numerically the differential equation of the Maxwell-Wiechert model with the Runge-Kutta-Fehlberg (RKF) numerical method. The coefficients of the elements of the Maxwell-Wiechert model were estimated approaching the straining curve of the recovery step of the simulation with the same curve registered on each experimental test. Experimental CCRTs with different unloading times demonstrated that the use of this procedure derived in no influence of the unloading step time in the viscoelastic properties estimation.

Thermodynamic Assessment of the Impact of Selected Plastics on the Energy Parameters of Explosives

Global economic development and the associated increase in consumption increase the demand for plastics. The result of these changes is the increase in the share of this group of used plastics in the structure of household waste. An innovative way of managing plastic waste is to use it as a component of a high-energy material. According to the conceptual assumptions, some plastics introduced into the structure of an explosive (Ex) in appropriate amounts can improve the energy parameters of a high-energy material. Modification of the composition of the explosive causes a change in its explosive and operational parameters. It also becomes necessary to develop a method of introducing an additional component. Computer programs for thermodynamic calculations are a tool for modeling the predicted energy parameters of an explosive. The performed simulations and modeling allow for the selection of appropriate compositions for laboratory and “in situ” tests. This reduces the number of field tests performed. This enables the more effective design of new explosive compositions. The use of waste plastics as a corrector of explosive properties may also be pro-environmental in nature through the use of a detonation method of their disposal and will reduce the cost of manufacturing the product. The conducted analyses showed that for three ANFO-type explosives containing 2% polyethylene—PE 2.0, 1% polypropylene—PP 1.0 and 1% polyurethane—PU 1.0, obtained energy parameters similar to ANFO and qualitatively and quantitatively similar structure of post-detonation gases.

Mangrove degradation retarded microplastics weathering and affected metabolic activities of microplastics-associated microbes

Currently, information on microplastics (MPs) weathering characteristics and ecological functions driven by MPs-associated microbes in mangrove ecosystems remains unclear, especially in the degraded areas. Herein, we compared the weathering characteristics of MPs in both undegraded and degraded mangrove sediments, and then explored the potential interactions between their weathering characteristics and microbially-driven functions. After 70 days of incubation, different MPs (including polyethylene PE, polystyrene PS, and polylactic acid PLA) were strongly weathered in mangrove sediments, with significant erosion features. Interestingly, more obvious weathering characteristics were found for MPs in the undegraded mangrove sediments. O/C ratio value of MPs in the undegraded sediments was 2.3–3.0 times greater than that in the degraded ones. Besides, mangrove degradation reduced network complexity among MPs-associated microorganisms and affected their metabolic activities. Bacteria involved in carbon cycle process enriched on nondegradable MPs, whereas abundant bacteria responsible for sulphur cycle were observed on PLA-MPs. Moreover, these relevant bacteria were more abundant on MPs in the undegraded mangrove sediments. Mangrove degradation could directly and indirectly affect MPs weathering process and microbially-driven functions through regulating sediment properties and MPs-associated microbes. During weathering, contact angle and roughness of MPs were key factors influencing the colonisation of hydrocarbon degradation bacteria on MPs.

Developing fire retardant composites of biodegradable polyethylene reinforced with agricultural wastes

Developing novel natural fiber thermoplastic composites is twofold effective. The Added-value of local agricultural wastes is enhanced and the environmental burden is reduced by less use of imported synthetic fibers and more recycling of agricultural waste. Material selection, parametric optimization, and characterization of biodegradable natural fiber thermoplastic composites with flame retardant properties are carried out in this work. Thermoplastic matrix is linear aliphatic low-density Polyethylene PE. [0–30 wt%] natural fibers of locally produced jute, corn silk, and Bagasse are used for reinforcing. Fibers are cut to different lengths after being alkali-treated. 16–24 % ammonium polyphosphate APP is used for fire retarding at different loadings. A coupling agent is added to link the polymer matrix with the fiber. 3% Ferric Stearate is used for biodegradability activation. The samples are produced using a compounding kneader at 180 °C. Mechanical, water absorption, and flame-retardant properties are characterized. The biodegradability index, which is an indication to what extent the products manufactured from the composite are eco-friendly, is being measured. Jute composites show the highest mechanical properties of 11 MPa ultimate strength and 8 GPa modulus of elasticity, whereas the corn silk composites have better performance of V-2 according to the UL94 flame retardancy test. Water absorption of 15% fiber content is reduced to 1%.

Marine Debris Management in the Parangtritis Beach Tourism Area, Yogyakarta During Covid-19 Pandemic

Parangtritis Beach, Yogyakarta, Indonesia, is one of the most visited tourist destinations for domestic and international tourists. These tourists are required to carry out health protocols by wearing masks during the COVID-19 pandemic. The high number of visits is linear with the generation of waste in tourist areas. Marine debris is defined as any solid material that settles, dumps, or is dumped, dumped, or disposed of in the marine and coastal environment. Efficient management of marine debris is a coordinated strategic approach to dealing with problems and inefficient law enforcement to improve the preservation of the marine environment. This study aimed to analyze the composition, characteristics, and management of marine debris in the Parangtritis Beach area during the COVID-19 pandemic. The amount of waste generated during the pandemic was recorded at 0.9 kg/m2.day. Sampling is carried out using the line transect method. The composition of waste consists of PET, PE, other plastics, biodegradable organics, and masks, each of which is 17.86%, 32.54%, 6.85%, 37.61% and 5.14%. Due to the COVID-19 pandemic, mask waste has become waste that has a new category, namely infectious. The characteristics of marine debris other than organic biodegradable tend to have a high calorific value so that it is possible to be processed by thermal processes. Thermal gravimetric analysis (TGA) shows that Polyethylene Terephthalate (PET), (Polyethylene) PE, and mask waste can be decomposed at a temperature of 260-550°C. Organic waste has been managed by processing Black Soldier Fly (BSF), while plastic waste can be processed into handicraft products. In contrast, the remaining plastic waste and masks are processed by a thermal process to allow waste to energy.

Impacts of Physical-Chemical Property of Polyethylene (Pe) on Depolymerization and Biodegradation in Insects Yellow Mealworms (Tenebrio Molitor) and Dark Mealworms (Tenebrio Obscurus) with High Purity Microplastics

Impacts of Physical-Chemical Property of Polyethylene (Pe) on Depolymerization and Biodegradation in Insects Yellow Mealworms (Tenebrio Molitor) and Dark Mealworms (Tenebrio Obscurus) with High Purity Microplastics

Wear of polyethylene and polyurethane elastomers used for components working in natural abrasive environments

This paper presents the results of research on an evaluation of the intensity of tribological wear of polymers used for machinery components. The research material consisted of four types of polyurethane and PE 1000 PE-UHMW polyethylene. The research on the intensity of abrasive wear employed two methods: ball-cratering and the spinning bowl method. The ball-cratering test was performed using an abrasive suspension made of distilled water and silicon carbide (SiC). For the “spinning bowl” method, clay was the abrasive material. Based on material mass and density loss measurements, volumetric wear of the samples, and the specific wear rate Kc was determined. According to the test results, polyethylene PE 1000 was characterized by the highest resistance to wear. In the spinning bowl test, a similar wear value was obtained for polyurethane elastomer of the highest hardness among the tested polyurethanes.

Polymers Sorption Properties towards Photosynthetic Pigments and Fungicides.

In the present work, extraction with a solvent (cold acetone) was used to extract the assimilation pigments from spinach leaves. Then, the sorption capacity of selected plastics granules (polyvinyl chloride—PVC, polypropylene—PP, polyethylene—PE of different densities) was tested for the selective isolation of chlorophylls. Quantification of chlorophylls by HPLC (Zorbax Eclipse XDB-C18 column, the mobile phase: Acetonitrile/methanol/ethyl acetate 6:2:2, v/v) was based on chlorophyll-a content as the most common chlorophyll. The performed experiments prove that PVC containing electronegative chlorine exhibits favorable interactions toward chlorophyll by creating stable molecular complexes. The Fourier Transform Raman Spectroscopy (FT-Raman) and the molecular modeling were used to elucidate the structure of the created complexes. The optimal extraction requirements, the mass of sorbent, water-acetone ratio, time, and the composition of the elution solvent were all established. The optimized extraction conditions ensured a maximum extraction yield of chlorophylls of 98%. The chlorophyll-rich sorbent was re-extracted by acetone, leading to the recovery of 91% of chlorophylls in one step, adding the possibility of its re-use. The proposed effective and ecological method of obtaining the green dye from plants is cheap, simple, and efficient, avoiding organic solvents, utilizing the most widely used synthetic polymers in the world, being products difficult for utilization. The possibility to remove chosen fungicides cyprodinil, chlorothalonil, and thiabendazone from plant extract by PVC was also examined. The described method proposes a new application of synthetic polymers, which meets the criteria of sustainable green chemistry, simultaneously reaching the growing demand for pure natural compounds in the pharmaceutical and food industries.

Spatially offset Raman scattering line-mapping as a potential tool for particle size analysis

A spatially offset Raman spectroscopy (SORS) line-mapping scheme was explored as a tool for the measurement of particle size. The proposed scheme is based on the fact that photon migration in powder packing varies as a function of the reduced scattering coefficient, which is directly related to the particle size of the sample. It is known that a smaller particle yields a larger reduced scattering coefficient. Therefore, recognition of the particle size-dependent photon migration (distribution) could be a means to determine the sample's particle size and SORS is a versatile tool for this purpose. Peak intensities acquired along the SORS mapping line are expected to decrease with an increase of the offset distance and the descending slope of the peak intensity can be translated into particle size, for example, a greater slope (steeper intensity decrease) for smaller particles yielding a narrower (denser) photon distribution. For the study, low-density polyethylene (LDPE) and middle-density PE (MDPE) powders with four particle sizes were measured. In each case, the slope of intensity decrease became less steep with the increase of particle size due to the broader photon distribution. A comparative analysis of LDPE and MDPE spectra found that the slope was steeper in the measurement of MDPE powder since the photon distribution was narrower owing to the high particle density. Together, these findings suggest that the proposed scheme is potentially expandable to measure particle sizes of samples with relevant prior calibration and provide useful information on sample composition also for chemical analysis.

Polymer packaging waste recycling: study of the pyrolysis of two blends via TGA

The aim of this work is the evaluation of thermal degradation temperatures of two polymeric blends constituted by polyethylene PE, polypropylene PP, polystyrene PS and poly(ethylene terephthalate) PET through TGA in a catalytic mode. These polymers are widely known for their everyday use as packaging materials worldwide. The need for recycling is evident, the searches try to combine the energy profit with the use of common oxides as catalysts. The oxides chosen to be studied were MgO CaO, BaO γ-Al2O3 and TiO2, all dried and powdered. The results indicate that truthfully the implication of MgO lowers the decomposition peak temperature for most cases. Thus, MgO has been chosen as a satisfactory catalyst since the low acidity of the others leads to no harm for the polymers. Two blends containing the commoner polymers have also been studied in order to simulate the real conditions in solid waste, namely Blend A: PE/PET/PP of 50/25/25 and Blend B: PE/PET/PP/PS/PVC of 40/25/20/10/5 mass ratio. The most impressive result regards the PVC involvement, since small ratio in the blend reduces the decomposition beginning below 100 °C.

Comparative analysis of kinetics and mechanisms for Pb(II) sorption onto three kinds of microplastics

Microplastics (MPs), a kind of novel contaminant, have potential to concentrate and transport heavy metals in the aquatic environment. This feature may affect the distribution and bioavailability of heavy metals. In order to determine the sorption behaviors of heavy metals onto the MPs, the sorption kinetics and mechanisms were investigated between the MPs (polyvinylchloride PVC, polyethylene PE, polystyrene PS) and Pb(II). The results suggested that the Pb(II) sorption onto the MPs were pH- and ionic strength-dependent. The sorption processes were best fitted by the pseudo-second-order model, and the rate-limiting steps were the intraparticle diffusion and final equilibrium process. The maximum sorption capacities of PVC, PE and PS were 483.1 μg/g, 416.7 μg/g and 128.5 μg/g under the condition of 0.01 M NaCl, pH 6.0, T = 298 K. The sorption rate constants were in the following order: PVC<PE<PS. According to the Fourier transformed infrared and X-ray photoelectron spectroscopy, no new bonds were formed between the MPs and Pb(II). Physisorption was the main driven force for Pb(II) sorption. In summary, the investigation reveals the Pb(II) sorption kinetics and mechanisms onto the MPs, which will improve the understanding of the interactions between the MPs and heavy metals.

Critical aspects on off-line pyrolysis-based quantification of microplastic in environmental samples

Although pyrolytic analysis of polymers allows a quantitative determination, reports on pyrolysis-based quantifications are very scarce, most probably as the result of some critical aspects that need to be considered. This is valid especially for environmental analysis of microplastics that require a detection at low concentrations in complex matrices.Therefore, an off-line pyrolysis approach to quantify five polymers representing the most relevant constituents of microplastics (polyethylene PE, polypropylene PP, poly(ethylene terephthalate) PET, polystyrene PS, poly(vinyl chloride) PVC) was studied. The analytical approach was critically evaluated and discussed covering the basic analytical parameters specificity, sensitivity, reproducibility and applicability on real samples.Off-line pyrolysis-based analysis of PS and PP provided the best results with a high specificity of pyrolysis products, very good limit of quantification around 1 to 3 μg based on S/N ratios as extrapolated from standard material analyses (without matrix effects) and a recovery from real sample matrix higher than 50%. Hence, for these synthetic polymers the presented analytical method exhibits a high potential for quantification at low concentration levels in real environmental samples. Although for PE a partly lower specificity of pyrolysis products, a little lower sensitivity and reproducibility but a very good recovery from real sample matrix can be summarized, the off-line pyrolysis-based approach seems to be applicable successfully also for PE.Analyses of PVC and PET revealed the highest inconsistencies and drawbacks in particular only minor specificity, less reproducibility and a low recovery. Thus, both polymers can be quantified only with a very low degree of reliance and need complementary analysis to verify the pyrolysis-based quantitative results.Noteworthy, most of the critical aspects revealed by this study are also worth discussing for on-line pyrolysis approaches.

Investigation of Polymer-70% Aluminum Powder Composite

Metals and polymers permutation in order to produce polymer metals composites attain new fascination and significance to several authors. The first effort to syndicate these two classes of materials was formulated in the earlier years of the 20^th era. In this article aluminum flakes were positively assimilated in polyethylene PE matrix to syndicate the valuable properties of metals and polymers. They extend to light weight, endurance to corrosion, brisk fabrication rates and a extensive range of moduli etc.

Investigation into the Suppression Effects of Inert Powders on the Minimum Ignition Temperature and the Minimum Ignition Energy of Polyethylene Dust

The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety. One effective principle is to add an inert material to a highly combustible material in order to decrease its ignition sensitivity. This paper deals with an experimental investigation of the influence of inert dust on the minimum ignition temperature and the minimum explosion energy of combustible dust. The experiments detailed here were performed in a Godbert–Greenwald (GG) furnace and a 1.2 L Hartmann tube. The combustible dust (polyethylene—PE; 800 mesh) and four inert powders (NaHCO3, Na2C2O4, KHCO3, and K2C2O4) were used. The suppression effects of the four inert powders on the minimum ignition temperature and the minimum explosion energy of the PE dust have been evaluated and compared with each other. The results show that all of the four different inert dusts have an effective suppression effect on the minimum ignition temperature and the minimum explosion energy of PE dust. However, the comparison of the results indicates that the suppression effect of bicarbonate dusts is better than that of oxalate dust. For the same kind of bicarbonate dusts, the suppression effects of potassium salt dusts are better than those of the sodium salt. The possible mechanisms for the better suppression effects of bicarbonate dusts and potassium salt dusts have been analyzed here.

Influence of the Accuracy of Determining the Inner Diameter of Pressure Polyethylene Pipes by the Amount of Head Loss by Length

The article presents the results of the analysis of the requirements of All Union State standard No18599-2001 to the thickness of the walls of pressure polyethylene pipes. An example of hydraulic calculation of a pipeline made of polyethylene PE 100 with a diameter d = 315 mm is considered. It is made in two versions - without taking into account and with allowance for dimensional tolerances stipulated by the requirements of the standard. The influence of the limitations on the thickness of the pipe walls on the values of their internal diameters and hydraulic characteristics is analyzed.

Simulation and design of individual neutron dosimeter and optimization of energy response using an array of semiconductor sensors

Abstract Many researches have been done to develop and improve the performance of personal (individual) dosimeter response to cover a wide of neutron energy range (from thermal to fast). Depending on the individual category of the dosimeter, the semiconductor sensor has been used to simplify and lightweight. In this plan, it’s very important to have a fairly accurate counting of doses rate in different energies. With a general design and single-sensor simulations, all optimal thicknesses have been extracted. The performance of the simulation scheme has been compared with the commercial and laboratory samples in the world. Due to the deviation of all dosimeters with a flat energy response, in this paper, has been used an idea of one semi-conductor sensor to have the flat energy-response in the entire neutron energy range. Finally, by analyzing of the sensors data as arrays for the first time, we have reached a nearly flat and acceptable energy-response. Also a comparison has been made between Lucite-PMMA (H 5 C 5 O 2 ) and polyethylene–PE (CH 2 ) as a radiator and B 4 C has been studied as absorbent. Moreover, in this paper, the effect of gamma dose in the dosimeter has been investigated and shown around the standard has not been exceeded.

Development of an HPLC/UV method for the evaluation of extractables and leachables in plastic: Application to a plastic-packaged calcium gluconate glucoheptonate solution

Calcium gluconate glucoheptonate (GGCa) is known to interact with glass containers, leading to the leaching of aluminum from the glass into the solution at toxic level. Therefore, plastic containers seem to be a preferable packaging alternative. Nevertheless, plastics contain potentially toxic additives which could be released into the solution. In order to study content container interaction between GGCa and two plastic containers (polypropylene PP and polyethylene PE containers), an HPLC-PDA method was developed to separate, detect and quantify eleven additives commonly found in plastic materials, with good limit of detection and quantification. This method was then applied to evaluate the compatibility between GGCa and the two plastic containers. After 3 months of storage at 25 °C, none of the eleven additives were detected in GGCa solutions. The safety concern threshold (SCT) and of the analytical evaluation threshold (AET) were evaluated to discriminate the need to identify and qualify unknown peaks.