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Fused filament fabrication (FFF) has been widely adopted due to its simplicity and cost‐effectiveness. But until now, its application materials are still limited. Polyolefin material is one of the most commonly used plastics. However, low‐density polyethylene (LDPE) is rarely used in FFF due to the inadequate strength of the filaments and the warpage of the printed parts. In this work, polystyrene (PS) is added to LDPE to obtain blend filaments. After that, the filaments are used to validate the possibility of in situ microfibrillation directly in the process. The results show that the addition of PS can significantly improve the bending strength, bending modulus, and hardness without affecting the heat resistance and crystal transition of the composite. Besides, the PS dispersed phase can form microfibers under the influence of the shear field. The formation of microfibers can significantly enhance the mechanical properties of composites. The tensile strength and Young's modulus increase by 140% and 221%, respectively. The warping deformation and surface morphology of printed parts are also improved. This study provides a new idea for utilizing low‐strength polyolefin in 3D printing and achieving performance enhancement. [ABSTRACT FROM AUTHOR]

Plastics have been consistently produced for their practicality and convenience; however, unmanaged plastics often end up in the ocean and decompose into nano-plastics through photolytic decomposition and weathering, negatively affecting marine life. This can eventually affect humans via the food chain, highlighting the need for effective solutions. Microbial biodegradation has been proposed as a solution to minimize the impact of nano-plastics on the environment, and degradation byproducts can be used in microbial metabolic pathways. In this study, 57 bacterial strains were isolated and identified from a waste treatment facility. Bacterial strains with lipase activity were selected on Tween80 agar plates. Additionally, strains capable of growing on minimal salt agar plates supplemented with low-density polyethylene (LDPE) beads were selected. Incubation in a minimal salt medium with LDPE beads as the sole carbon source led to the selection of Pseudomonas plecoglossicida SYp2123, which is capable of degrading LDPE. This strain was subjected to high cell density culture, and Fourier-transform infrared spectroscopy revealed chemical changes on the surface of LDPE beads. Additionally, field-emission scanning electron microscopy confirmed substantial biodegradation of the surface. P. plecoglossicida SYp2123 was able to degrade LDPE beads. This discovery shows that P. plecoglossicida can potentially be used as an environmentally friendly approach for tackling issues associated with polyethylene waste. [ABSTRACT FROM AUTHOR]

A multi-objective optimization (MOO) technique to produce a low-density polyethylene (LDPE) is applied to address these two problems: increasing conversion and reducing operating cost (as the first optimization problem, P1) and increasing productivity and reducing operating cost (as the second optimization problem, P2). ASPEN Plus software was utilized for the model-based optimization by executing the MOO algorithm using the tubular reactor model. The multi-objective optimization of multi-objective Bonobo optimisers (MOBO-I, MOBO-II and MOBO-III) are utilised to solve the optimization problem. The performance matrices, including hypervolume, pure diversity, and distance, are used to decide on the best MOO method. An inequality constraint was introduced on the temperature of the reactor to prevent run-away. According to the findings of the study, the MOBO-II for Problems 1 and 2 was the most effective MOO strategy. The reason is that the solution set found represents the most accurate, diversified, and acceptable distribution points alongside the Pareto Front (PF) in terms of homogeneity. The minimum operating cost, the maximum conversion and productivity obtained by MOBO-II are Mil. RM/year 114.3, 31.45 %, Mil. RM/year 545.3, respectively. [ABSTRACT FROM AUTHOR]

To fulfil the European Green Deal targets and implement a circular economy, there is an urgent need to increase recycling rates of packaging materials. However, before recycled materials can be used in food contact applications, they must meet high safety standards. According to the European Food Safety Authority (EFSA), a worst-case scenario must be applied and unknown substances must be evaluated as being potentially genotoxic. The Ames test, which detects direct DNA-reactive effects, together with chromatographic analysis is very promising to complement risk assessment. This study aims to evaluate the effectiveness of functional barriers in ten different samples, including virgin and recycled LDPE foils. FT-IR analysis did not show major differences between virgin and recycled films. Light microscopy revealed differences in quality and an increased number of particles. GC-MS analysis detected and quantified 35 substances, including eight unknowns. Using a miniaturized version of the Ames test, four of ten samples tested positive in two individual migrates up to a dilution of 12.5%. All virgin LDPE materials tested negative; however, recycled material F showed an increased mutagenic activity, with an n-fold induction up to 28. Samples with functional barriers lowered migration and reduced mutagenicity. Nonetheless, further investigations are needed to identify possible sources of contamination. [ABSTRACT FROM AUTHOR]

The co-pyrolysis of polyethylene terephthalate (PET) with low-density polyethylene (LDPE) and high-density polyethylene (HDPE) was carried out in a batch steel pyrolyzer in order to convert the PET into pyrolysis oil as its pyrolysis alone resulted in wax and gases. The study also aimed to increase the aromatic content of pyrolysis oil by the interaction of degradation fragments of linear chains of LDPE and HDPE with the benzene ring of PET during the pyrolysis. The reaction conditions were optimized for a higher yield of pyrolysis oil which were found to be 500 °C pyrolysis temperature with a heating rate of 0.5 °Cs−1, 1 h reaction time and 20 g of the initial mass of polymer mixture having 20% PET, 40% LDPE and 40% HDPE. Waste aluminium particles were applied as an economical catalyst in the process. The thermal co-pyrolysis yielded 8% pyrolysis oil, 32.3 wax, 39.7 wt% gases and 20% coke while the catalytic co-pyrolysis produced 30.2% pyrolysis oil, 4.2% wax, 53.6 wt% gases and 12% coke. The fractional distillation of catalytic oil resulted in 46% gasoline range oil, 31% kerosene range oil and 23% diesel range oil. These fractions resembled the standard fuels in terms of their fuel properties as well as FT-IR spectra. The GC-MS analysis revealed that the catalytic co-pyrolysis favoured the formation of relatively short-chain hydrocarbons with olefins and isoparaffins as major components while the thermal co-pyrolysis formed long-chain paraffins. The naphthenes and aromatics were also found in higher amounts in the catalytic oil compared with the thermal oil. [ABSTRACT FROM AUTHOR]

Polymer-modified bitumen undergoes phase separation during storage due to a lack of compatibility between the polymers and bitumen. However, phase separation can be minimized via the addition of various compatibilizers. This study investigated low-density polyethylene (LDPE)-modified bitumen blends at 3, 6, 9, and 12% concentration of LDPE sourced from waste plastic films. Furthermore, the combined compatibilizers (1% of maleic anhydride-grafted polyethylene (PE-g-MA) and 0.15% sulfur) were added to LDPE-modified blends. The combination of compatibilizers significantly improved the softening point and storage stability while subsequently increasing the compatibility between recycled plastics (LDPE) and bitumen. The addition of PE-g-MA and sulfur decreased the melting temperature of LDPE up to 10 °C due to the swelling of the polymers compared to blends prepared with LDPE only. Higher thermal stability was observed for LDPE blends with PE-g-MA and sulfur than for the blends with LDPE only. The major weight loss for LDPE–based blends and LDPE blends in the presence of PE-g-MA and sulfur occurred at 380–520 °C and 400–540 °C, respectively. LDPE blends in the presence of compatibilizers showed lower phase angle at higher temperatures than neat LDPE blends, suggesting that the compatibilizers tend to form a complete polymer–bitumen network. It was concluded that incorporation of both sulfur and PE-g-MA enhanced the compatibility, thermal characteristics, and rheological properties of waste plastic-modified bitumen. [ABSTRACT FROM AUTHOR]

A study was carried out on the luminescence excitation spectra and photoluminescence (PL) spectra as well as the luminescence kinetics of low-density polyethylene composites with different contents of CaGa2S4:Eu2+ phosphor filler. The phospholuminescence was attributed to the 4f65d → 4f7 transition of the Eu3+ ion and was greatest when the filler concentration was 7 vol.%. The dependence of the PL intensity on the excitation power density up to 0.3 W/cm2 was found to be linear, indicating that these phosphors can be used as visible radiation sources in various lighting systems. [ABSTRACT FROM AUTHOR]

The present work explores the shear and extensional rheology of immiscible multi-micro/nanolayered systems comprising low-density polyethylene (LDPE) paired with polystyrene (PS) and polycarbonate (PC) obtained from forced-assembly multilayer coextrusion. Firstly, miscible multilayer references based on LDPE/LLDPE layers were prepared with their miscibility characterized by shear and elongational measurements. Their strain hardening behaviors were found to be intricately linked to the number of layers and confinement. Secondly, for immiscible LDPE/PS and LDPE/PC multilayers with symmetric (50/50) and asymmetric (10/90) compositions, negative deviation of complex viscosities from neat polymers was highlighted because of the heightened confinement of LDPE chains by PS or PC and reduced entanglements at polymer–polymer interfaces. Intriguingly, LDPE/PC systems exhibited no strain hardening irrespective of layer configuration, while the geometric confinement imposed by PS layers facilitated interactions between single chains with long-chain branching (LCB), leading to strain hardening under specific conditions. Furthermore, the extensional viscosities were predicted using the Macosko model (C.W. Macosko et al. Journal of Rheology. 63 2019), accurately describing the behavior of 1024 layered films for both asymmetric (10/90) LDPE/PS and LDPE/PC systems, but not for 32 layers due to a limited number of interfaces. This study provides insights into quantifying interfacial tension properties in micro/nano-layered systems with high mismatched viscoelastic polymers, shedding light on their strain hardening properties in the presence of increased interfacial area. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Low-density polyethylene is one of the dominant recalcitrant plastic pollutants in the ocean, thus causing complicated problems. Biodegradation is an efficient, environmentally friendly, and sustainable option to overcome these problems. This study aims to quantitatively and qualitatively analyze the ability of marine bacterial isolates to degrade lowdensity polyethylene plastic. METHODS: Bacteria were isolated from plastic samples using serial dilution technique and inoculated on media containing low-density polyethylene powder. Bacterial degradation ability was analyzed quantitatively based on weight loss percentage and energy-dispersive X-ray spectroscopy values, as well as qualitatively based on changes in physical and chemical structures using Scanning Electron Microscopy and Fourier transform infrared spectroscopy. Meanwhile, bacterial isolates were identified based on gene sequence and phylogenetic analyses. FINDINGS: Four bacterial isolates were isolated from low-density polyethylene plastic samples. Quantitative analysis found that the low-density polyethylene film experienced weight loss up to 10-15 percent during 35 days of incubation, with a maximum daily weight loss rate of 0.004 milligrams per day, meaning that the four bacterial isolates have the potential to degrade plastic. Meanwhile, qualitative analysis based on Scanning Electron Microscope observations revealed changes in the physical structure of the film surface in the form of a rough surface, formation of holes, and breakdown into clumps across the film surface. Variations in these changes were tested. In the control, no changes occurred and the film surface remained flat and smooth. Conversely, the results of the energy dispersive X-ray spectroscopy spectrum analysis showed that the lowdensity polyethylene film broke down into smaller fragments, characterized by a decrease in mass from 98.51 percent to 98.23 percent. Fourier transform infrared observations showed variations in transmittance and wavenumbers, indicating changes in chemical bonds or functional groups in the low-density polyethylene film which caused it to become brittle and break down into smaller fragments with a lower molecular weight, making it easier for bacteria to digest. The results of the gene sequence analysis identified four bacterial isolates, namely Lysinibacillus sp. IBP-1, Bacillus sp. IBP-2, Bacillus paramycoides IBP-3, and Bacillus cereus IBP-4. Based on the quantitative and qualitative analyses, the ability of the bacterial isolates to degrade low-density polyethylene film was shown in the following order: Bacillus paramycoides IBP-3 > Bacillus cereus IBP-4 > Lysinibacillus sp. IBP-1 > Bacillus sp. IBP-2. CONCLUSION: All four marine bacterial isolates can use low-density polyethylene as the sole carbon source. Based on quantitative and qualitative analyses, Bacillus paramycoides IBP-3 has the best potential for degrading low-density polyethylene film. This study provides information on potential bacterial isolates that can be developed to control low-density polyethylene plastic waste. [ABSTRACT FROM AUTHOR]

Global plastic pollution is one of the serious issues which create a severe environmental damage. Microbial biodegradation is an eco-friendly method to overcome the plastic pollution issue. The aim of this study is to explore microbes from garbage soil to manage the Low-density Polyethylene (LDPE). Active biodegrading microbes were identified by clear zone method using mineral salt medium with LDPE. Genome sequencing has been performed for LDPE-degrading strains and identified as Bacillus subtilis and Streptomyces labedae. The biodegradation of LDPE was carried out by using selected active strains. The analysis of biodegradation process was carried out by extracellular enzyme assay, cell hydrophobicity and viability of cells with elevated pH produced by B.subtilis and S.labedae. The weight loss percentage of polymer sheets by B.subtilis and S.labedae were 80% and 85% respectively. Major deformities and surface modification on the LDPE sheet were evaluated by the formation of cracks and pits on the surface. The functional groups in the treated sheets were observed by using FTIR analysis. The highest reduction in tensile strength was observed. The GC-MS analysis revealed the presence of 30 new compounds during the biodegradation. It evolved CO2 of 5.32 g/l with S. labedae and 4.55 g/l with B.subtilis. Phytotoxicity of LDPE degraded byproduct showed a positive growth rate of 97.8 ± 0.836% in Trigonella foenum seed. Then the cytotoxicity study revealed that it was non-toxic to L292 cell lines. Both strains have the ability to consume and reduce the LDPE film. These organisms are the promising resources to manage the LDPE and offers an ecofriendly solution to solve global plastic pollution. Hence the achieved research information could be applied at a large scale for degrading various plastic materials. [ABSTRACT FROM AUTHOR]

In tubular reactors, fouling issues are caused due to two reasons. One is the heating–cooling prerequisite, and the other is the exothermic nature of the low‐density polyethylene (LDPE) polymerization process. These issues must be considered while optimizing LDPE production to provide maximum productivity and a safe operation. However, it is not a simple process because the conversion of the monomer (XM) is generally related to significant profits. This conversion might be performed at high reaction temperatures, resulting in fouling formation. Therefore, in this research, a study of dynamic optimization to find the most efficient production of LDPE in the presence of fouling resistance (Rf) restrictions is conducted. An Rf is employed as a measure of fouling. To establish the highest reactor RfRfmax=50cm2sK/cal$$ \left({R}_{f_{\mathrm{max}}}=50\ \mathrm{cm}2\ \mathrm{s}\ \mathrm{K}/\mathrm{cal}\right) $$, this study employs variations in the heat transfer coefficient (U) calculated from industry data. This dynamic optimization study addresses the optimization challenges using dynopt coded programming based on orthogonal collocation (OC) and sequential quadratic programming methodologies. Beforehand, the LDPE model is validated with industrial data. This study evaluates three possibilities to determine the most optimum reactor performance. The most optimum reactor output is determined from the constrained maximum conversion, which gave 32.15% conversion, while the Rf$$ {R}_f $$was effectively met at 47.37cm2 s K/cal. [ABSTRACT FROM AUTHOR]

The global problem of microplastics in the environment is "inspiring" scientists to find environmentally friendly and economically viable methods to remove these pollutants from the environment. Advanced oxidation processes are among the most promising methods. In this work, the potential of Fenton, photo-Fenton, and Fenton-like processes for the degradation of microplastics from low-density polyethylene (LDPE), polypropylene (PP), and poly(vinyl chloride) (PVC) in water suspensions was investigated. The influence of three parameters on the efficiency of the degradation process was tested: the pH of the medium (3–7), the mass of added iron (10–50 times less than the mass of microplastics), and the mass of added H2O2 (5–25 times more than the mass of added iron). The effectiveness of the treatment was monitored by FTIR-ATR spectroscopy. After 60-min treatments, the PP microparticles were found to be insensitive. In the Fenton treatment of PVC and the photo-Fenton treatment of LDPE and PVC, changes in the FTIR spectra related to the degradation of the microplastics were observed. In these three cases, the treatment parameters were optimized. It was found that a low pH (3) and a high iron mass (optimal values were 1/12 and 1/10 of the mass of the microplastics for LDPE and PVC, respectively) favored all three. The degradation of LDPE by the photo-Fenton treatment was favored by high H2O2 concentrations (25 times higher than the mass of iron), while these concentrations were significantly lower for PVC (11 and 15 times for the Fenton and photo-Fenton treatment, respectively), suggesting that scavenging activity occurs. [ABSTRACT FROM AUTHOR]

Triple shape memory materials currently have a wide range of applications in aerospace and healthcare. In this study, Organic clay (OC) was introduced as a reinforcing phase in trans-isoprene (TPI) and low-density polyethylene (LDPE) matrix. TPI/LDPE/OC shape memory composites (SMP) were prepared by melt blending and vulcanized and pressed using dynamic vulcanization technique. In order to reveal the effect of OC content on the mechanical and shape memory properties of TPI/LDPE/OC composites, a series of experiments were conducted. The results show that the optimum vulcanization time of the composites decreases linearly with increasing OC content. The torque difference of the composites is maximized when OC is added at 2 phr, which indicates that the cross-linking degree of the composites is optimal at this time; In addition, with the increase of OC content, the mechanical properties, crystallization properties and shape memory properties of the composites first increase and then decrease. This is due to the fact that OC can form a stable and homogeneous interlayer structure with the composite matrix in the appropriate amount, which will play a role in enhancing the properties, but when OC is added in excess, agglomeration occurs within the composite matrix, thus reducing the properties; The crosslinking degree, tensile strength, crystallinity and triple shape memory properties of the composites were optimized when the OC content was 2 phr. This study provides potential value for research on the application of multiple shape memory materials. [ABSTRACT FROM AUTHOR]

Due to the intensive search for new types of advanced polymer materials for targeted applications, this work offers insight into the properties of low-density polyethylene/hematite composites. The specific feature of this study lies in the use of elongated hematite particles of different shapes. Uniform ellipsoid-, peanut- and rod-shaped hematite particles were hydrothermally synthesized and incorporated into the polymer matrix of low-density polyethylene (LDPE). LDPE/hematite composites are prepared by melt mixing. Hematite particles are characterized by scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD). The pure LDPE polymer and LDPE/hematite composites were studied by FT-IR and UV-Vis-NIR spectroscopy and by thermogravimetric analysis (TGA). The determination of the mechanical and barrier properties was also carried out. The obtained results indicate the influence of the elongated particles on the improvement of LDPE properties. An increase in thermal stability and UV-absorption was observed as well as the improvement of mechanical and barrier properties. The improvement of the composites' properties in comparison to the pure LDPE is especially visible in the composites prepared with low content of hematite (0.25%). LDPE/hematite composites have promising characteristics for application as packaging materials with enhanced mechanical, thermal and barrier properties as well as UV-protective materials. [ABSTRACT FROM AUTHOR]

In this study, three commercially available low‐density polyethylene (LDPE) polymers produced via a tubular reactor process, with varying melt flow rates at 190°C/2.16 kg (4.0, 1.9, and 0.75 g/10 min), have been selected and subjected to high temperature‐size exclusion chromatography (SEC) analysis coupled with an infrared‐5 (IR‐5), viscometer (VISCO), and multiangle laser light‐scattering detectors. The molecular weight (MW), MW distribution, short‐chain branching (SCB), and long‐chain branching parameters were investigated. It was found that MW obtained by the universal technique (∼1.57–1.7 times) and multiangle laser light‐scattering detection technique is (∼1.43–1.55 times) higher than that of the conventional calibration technique, which could be attributed to structural complexity associated with LDPEs which is not clearly understood by conventional SEC mode alone. The bulk SCB per 1000 total carbon atoms estimated by IR‐5 detection was found to range from 16.50 to 17.80. On the other hand, long chain branching frequency per 1000 total carbon atoms obtained by online VISCO and multiangle laser light‐scattering detection ranged from 0.46 to 0.54 and 0.65 to 0.94, respectively. Further, the significance of long chain branching parameters on the polymer processing behavior was studied in correlation with rheological property (Die swell ratio). [ABSTRACT FROM AUTHOR]

The production of composites, using waste materials as matrix and reinforcement, is an innovative, environmentally relevant, and economically viable alternative, regarding the environmental problems generated by inappropriate disposal. This study aimed to produce and characterize the technological properties of composites based on low-density polyethylene produced by extrusion with proportions of 0, 10, 20, 30, and 40% of cotton-seed cake residue (reinforcement) replacing the polyethylene mass (matrix). The composites were characterized for their physical–mechanical and morphological properties. The inclusion of cotton residue promoted an increase in moisture, from 0.05 to 0.37%, in water absorption 24 h (0.05 to 1.2%) and in thickness swelling (0.8 to 2.1%). The composites density did not show significant variation with the increase in the waste content. Regarding the mechanical properties, there was a decrease of 28, 52, and 81% for the modulus of elasticity, tensile, and tenacity, respectively. The results were similar when compared to other residual composites. In this way, it was possible to give a correct destination to the waste of low-density polyethylene and cotton-seed cake, producing a final material with high added value. [ABSTRACT FROM AUTHOR]

There has been growing interest in the use of polyethylene (PE) in the asphalt industry as one way to mitigate the adverse environmental impact of waste plastics. The main goal of this study was to evaluate the potential use of low-density polyethylene (LDPE) as a modifier for use in asphalt mixtures. In addition, this study also explored the potential synergistic impact of using elastomeric polymers typically used with asphalt binders as a co-modifier along with LDPE. This study was based on a comprehensive evaluation of the rheological and performance-related properties of asphalt binder from two very different sources as well as asphalt mixtures produced using a subset of these binders. Typical methods that are standard practice in the industry and methods that are being developed to evaluate the performance metrics of asphalt binders and mixtures were used. The two chemically diverse base binders and redundancy in the evaluation process were introduced to ensure a more robust evaluation of the expected properties. Overall, results demonstrate that although the impact of LDPE on the expected performance of the binder may vary with the source of binder, LDPE can be successfully used to enhance the properties of the asphalt binder in most respects, particularly with the synergistic use of a conventional elastomeric modifier. [ABSTRACT FROM AUTHOR]

It is proverbial that the rheological properties of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are disparate because of their different molecular microstructures due to the unlike methods of polymerization. In this work, multiple characterizations including Size-Exclusion Chromatography (SEC) coupled with low-angle light scattering and viscosmeter, 13C Nuclear Magnetic Resonance, Crystallization Elution Fractionation (CEF) and Differential Scanning Calorimetry (DSC) were conducted to get detailed information of branching on different LDPEs and LLDPEs. It was found that, in our case, LDPEs possessed higher molecular weight and greater amounts of long-chain branching (LCB) in comparison with LLDPEs. The Chemical Composition Distribution (CCD) of each LLDPE sample depends strongly on the catalyst used. LLDPE produced by Z-N catalyst exhibited broad short-chain branching (SCB) distribution (less uniform composition distribution), whereas LLDPE obtained by metallocene catalyst showed more uniform microstructure. Unlikely, the two LDPEs displayed wider but unimodal distribution corresponding to the free-radical polymerization mechanism. Both linear and nonlinear rheological results were strongly influenced by the presence of LCB. LDPEs in this work exhibited higher zero shear-viscosity, higher values of storage modulus, longer relaxation times, and higher activation energy comparing to LLDPEs. The presence of LCB leads to more pronounced strain hardening behavior in the elongational flow which is neglected in LLDPE. The molecular structures of linear and branched PEs were consistent with the rheological properties. [ABSTRACT FROM AUTHOR]

This study investigated the compatibility of waste plastic, a serious environmental and recycling concern, with styrene-butadiene-styrene (SBS) in asphalt binders. An extensive storage stability analysis of binders modified with varying dosages of low-density polyethylene (LDPE) from postcommercial usage with SBS as a compatibilizer and the understanding of behaviors of each component was conducted in this study. Although SBS-LDPE blends were stable with separation index in terms of G*/sin δ , percent recovery from multiple stress creep recovery (MSCR) detected nonhomogeneity of polymer dispersion in the asphalt blend. To address this nonhomogeneity, waste cooking oil was used to pretreat LDPE to enhance the dispersion and reaction with the binder. Ultimately, 4.5% SBS + 1.5% oil-treated LDPE (TLDPE) was observed to yield a stable SBS-TLDPE blend with a top-bottom separation index ratio of 1.0 in terms of G*/sin δ and percent recovery difference of 3.5% and 1.4% at 0.1 and 3.2 kPa, respectively. The study identified that the presence of LDPE negatively influences the recovery and cracking performance of asphalt binders at low temperatures. From critical temperature differential (ΔTc), Glover-Rowe (G-R) parameter and Black space diagrams at different aging levels, it was concluded that unlike SBS, SBS + LDPE combination had resistance against extended long-term aging. [ABSTRACT FROM AUTHOR]

Date palm tree leaf-reinforced polymer composites have important advantages, such as sustainability and lowcost. In the present study, ternary blend composites of polyvinyl chloride (PVC), low-density polyethylene (LDPE), and acrylonitrile butadiene rubber (NBR) copolymer (LDPE/PVC: C0, LDPE/PVC/NBR:C1) as well as reinforced composites with 10, 20, and 30 wt.% of alkali treated date palm fiber (TDPF) (C2, C3 and C4 respectively) were fabricated using a melt blending extrusion process. TDPF and the NBR copolymer were used to improve the interfacial bonding, compatibility, and thermo-mechanical properties of the composite, yielding the highest tensile strength of 32 MPa for the composite containing 10 wt.% TDPF. Moreover, the morphological analysis showed that the incorporation of the NBR copolymer enhanced the compatibility of the blend. Mechanical tests revealed that the hardness of the TDPF/PVC/LDPE/NBR composite increased in the order C2 (450 MPa) < C3 < C4 (540 MPa). In addition, the flexural and tensile moduli of the composite increased with increasing TDPF content, with the highest values (534 and 1585 MPa, respectively) observed for composite C4. Thermal analysis revealed increased Tonset and T10% values, indicating an improved thermal stability of the composite. This study clearly demonstrates that the (DPF/PVC/LDPE/NBR) composites can be used in various high-tech engineering applications, which require excellent properties. [ABSTRACT FROM AUTHOR]

The focus of the present work is to prepare low‐density polyethylene (LDPE)‐graphene (G) nanocomposite films with improved gas barrier properties by melt extrusion. A narrow range of the graphene (0.05–0.3 wt.%) as filler was used in the LDPE matrix. The rheological analysis indicating that there is no significant influence on the LDPE chains mobility with the addition of filler. The nanocomposites percent crystallinity (Xc%) increase from 25.0% to 31.6% compared to neat LDPE. The X‐ray diffractogram shows a change in width half height of the peak positioned at 26° ((002) plane) from 0.69 (graphite) to 1.24 (graphene), revealing the asymmetry of this plane. The optical microscopy images show a good dispersion of the nanoparticles in the polymer matrix. The mechanical properties of the nanocomposites in longitudinal direction demonstrate better improvement with addition of the filler as compared to the transverse direction. The contact angle measurements of nanocomposites for water and ethylene glycol do not shows a significant variation in comparison to neat LDPE. The nanocomposites show 26% enhancement in the oxygen barrier property. Thus, here we present the cost‐effective LDPE‐graphene nanocomposites with improve oxygen barrier property, which can be used in different industrial application especially in food packaging. [ABSTRACT FROM AUTHOR]

Environmental and social concerns due to the generation of huge amounts of waste and their improper disposal are some of the serious challenges faced by contemporary civilisation. In the present study, the feasibility of waste-based composites (WBC) which were developed using banana stalk fibres and waste low-density polyethylene (LDPE) was characterised and studied. Pre-treated and untreated banana fibres were added as reinforcement to the LDPE matrix with different weight percentages of 0, 10, 15, 20 and 25%. Mercerisation process was undertaken as the pre-treatment method and 5% (by weight) of NaOH solution was used. WBC sheets were developed using hand lay-up process, and with hot press and cold press machines. Density, uniaxial tensile and water absorption tests were conducted for the developed WBC. Density, Young's modulus, yield stress, yield strain, ultimate stress, failure strain, resilience modulus, toughness modulus and saturated water absorption were analysed to characterise their properties. The findings indicated that with the addition of banana fibres, enhancements in density, Young's modulus, yield stress, maximum stress, resilience modulus and water absorption capacity were observed while showing reductions in yield strain, failure strain and toughness modulus compared to unreinforced waste-based LDPE sheets. By considering the overall results, 20 and 15% of optimum fibre additions were observed for pre-treated and untreated fibres, respectively, and mercerisation has positively attributed to the characteristics of WBC. [ABSTRACT FROM AUTHOR]

Smart packaging relies on the one‐to‐one interaction of food with its packaging or its environment to monitor food quality and safety. Colorimetric pH indicators (synthetic, natural) working in a smart food packaging system are particularly striking when used with fresh foodstuffs such as fish and meat that perish quickly and require real‐time freshness monitoring. In this study, curcumin (Cur) was used as a natural pH indicator to produce sustainable smart packaging material. Towards this objective, low‐density polyethylene (LDPE) and thermoplastic starch (TPS) blend‐based films containing Cur were prepared using a twin screw extrusion and hot‐pressing processes. Besides, two different compositions of LDPE/TPS mixture (50/50 and 70/30) were used as the matrix. Thermal, mechanical, morphological properties, an affinity for water, and color change properties of LDPE/TPS/Cur films were investigated. They showed a significant color change from yellow to brown at pH: 10 at the end of the seventh day, especially in the 50 LDPE/50 TPS mixture. 50 LDPE/50 TPS mixture with 7% curcumin content gave the highest tensile strength of 8.03 Mpa. When the same mixture was used to monitor chicken meat spoilage at 25°C, meat samples have shown color changes from light yellow to light brown due to the increased content of total volatile basic amines. As a result, it has been suggested that 50 LDPE/50 TPS mixture containing 7% Cur can be used as a smart packaging material. [ABSTRACT FROM AUTHOR]

In recent years, research into replacing synthetic fibers with natural fibers as reinforcements in thermoplastic composites has developed rapidly. The main objective of this work is to produce eco-friendly and cost-effective composite material. This material consists of natural fiber of sugarcane bagasse as the reinforcing component and thermoplastic polymer of low-density polyethylene as a matrix. The injection molding technique was used to produce the test samples. The fabricated composite contained 30 wt.% sugarcane bagasse. The effects of natural fiber sugarcane bagasse content, chemical treatment, and the addition of maleic anhydride as coupling agent on the composite degradation were studied. The degradation of sugarcane bagasse/low-density polyethylene composite under ultraviolet radiation and the thermal degradation were investigated. In addition, the amount of absorbance ultraviolet radiation by the fabricated composites was studied using ultraviolet-visible spectroscopy in the range from 200–800 nm. The effect of carbon black particles added to the fabricated composite on the degradation by ultraviolet exposure was also investigated. The results showed that the compatibilized sugarcane bagasse/low-density polyethylene composites at 3 wt.% maleic anhydride concentration revealed a higher decomposition temperature (466°C) than that of the uncompatibilized composites (460°C). This ensures that the thermal degradation temperature was improved by using the maleic anhydride coupling agent. Moreover, using the coupling agent showed significant resistance to degradation by ultraviolet exposure. Furthermore, the addition of 2.5 wt.% carbon black enabled more resistance to degradation by ultraviolet exposure. [ABSTRACT FROM AUTHOR]

Plastic waste elimination is more important for environmental pollution. Alternate fuel is essential for future IC engine applications because of fossil fuel availability. This study focuses on both challenges by creating combustion energy for direct injection CI engines from the wastes with lesser NOx emissions. Plastic wastes of low-density polyethylene (LDPE) have the most negligible recycling value based on their collection point of view from municipal wastes. Conversion of this LDPE plastic waste into alternate fuel for CI engines by pyrolysis will provide value for that waste. The combustion, emission, and performance of neat pyrolyzed oil of LDPE plastic wastes (POLPW) were studied with exhaust gas recirculation (EGR; 0%, 10%, and 20%) in a 1500 rpm 5.2 kW engine on different loads. 20% of EGR used POLPW fuel produced 31.63% of brake thermal efficiency and 62.28% reduction in NOx (596 ppm) than diesel at maximum load. Pyrolyzed oil of low-density polyethylene plastic wastes can be utilized as a 100% substitute fuel in CI engines with an EGR of 20%. This will provide alternate fuel and low-value plastic waste downcycling, initiating environmental pollution reduction. [Display omitted] • Using one time used plastic waste to generate combustion energy for engine. • Downcycling of low-density polyethylene environment waste by pyrolysis with 80% yield. • Neat pyrolyzed LDPE oil usage is possible with all loads in the engine. • Neat oil with 20% exhaust recirculation have 31.36% brake thermal efficiency. • Compared to diesel, 62.82% of NOx emissions were reduced. [ABSTRACT FROM AUTHOR]

Τhe replacement of food packaging additives and preservatives with bio-based antioxidant/antibacterial compounds has been a common practice in recent years following the trend of bioeconomy and nanotechnology. Such bio-additives are often enclosed in nanocarriers for a controlled release process. Following this trend in this work, a thymol (TO)-rich activated carbon (AC) nanohybrid was prepared and characterized physicochemically with various techniques. This TO@AC nanohybrid, along with the pure activated carbon, was extruded with low-density polyethylene (LDPE) to develop novel active packaging films. The codenames used in this paper were LDPE/xTO@AC and LDPE/xAC for the nanohybrid and the pure activated carbon, respectively. X-ray diffractometry, Fourier-transform infrared spectroscopy, and scanning electron microscopy measurements showed high dispersity of both the TO@AC nanohybrid and the pure AC in the LDPE matrix, resulting in enhanced mechanical properties. The active film with 15 wt.% of the TO@AC nanohybrid (LDPE/15TO@AC) exhibited a 230% higher water/vapor barrier and 1928% lower oxygen permeability than the pure LDPE film. For this active film, the highest antioxidant activity referred to the DPPH assay (44.4%), the lowest thymol release rate (k2 ≈ 1.5 s−1), and the highest antibacterial activity were recorded, resulting in a 2-day extension of fresh pork fillets' shelf-life. [ABSTRACT FROM AUTHOR]

Plastic waste generated from the widespread use of low-density polyethylene (LDPE) has raised significant environmental concerns due to its slow degradation. This review article explores the progress in LDPE nanocomposites for photodegradation, emphasizing strategies, mechanisms, and applications. Incorporating inorganic nanoparticles like titanium dioxide (TiO2), zinc oxide (ZnO), and iron oxide (Fe2O3) into LDPE has been examined to enhance its properties and biodegradability. These nanoparticles strengthen LDPE's mechanical, thermal, and barrier characteristics, thereby improving its overall performance. Various techniques have been employed to optimize the concentration and size of nanoparticles to attain the desired properties. Photodegradation, employing sunlight to break down LDPE into smaller fragments, has effectively decomposed plastic waste and reduced its environmental impact. Artificial UV light sources and additives like sensitizers and biological agents such as enzymes and microorganisms can enhance photodegradation. The incorporation of inorganic nanoparticles in LDPE significantly improves its properties and biodegradability. Research into LDPE nanocomposites for their degradation under sunlight shows potential in addressing the environmental challenges caused by plastic waste. This advancement opens the door to a wide range of applications for LDPE nanocomposites, offering a sustainable alternative to traditional plastics. [ABSTRACT FROM AUTHOR]

Paraffin phase change materials (PCMs) exhibit great potential in battery thermal management (BTM); nevertheless, their application has been hampered by the handicap of low thermal conductivity, leakage, and volume expansion during phase transition. In this work, ternary composite PCMs formed of paraffin, expanded graphite (EG), and low-density polyethylene (LDPE) were developed for application in BTM. The structure and properties of the composite PCMs were characterized via X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, and thermal constant analysis. The result shows that EG can form a large-size graphite frame as heat conduction paths to improve the thermal conductivity of the composite PCM, and LDPE can form an interpenetrating network within the composite PCM to resist the internal stress of paraffin expansion and prevent deformation. The latent heat and thermal conductivity of the composite PCMs loaded with 10 wt% EG and 4 wt% LDPE can reach 172.06 J/g and 3.85 Wm−1K−1 with a relatively low leakage ratio of 6.2 wt%. Remarkably, the composite PCMs could reduce the temperature rise of the battery by 55.1%. In brief, this work provides a feasible route to develop high-performance PCMs for BTM. [ABSTRACT FROM AUTHOR]

Mixing in low‐density polyethylene (LDPE) reactors is crucial regarding process safety as well as process efficiency. The extreme process conditions of pressures up to 3000 bar make it difficult to get an insight into LDPE reactors. This problem is tackled by a combined experimental and modeling approach. A poly(methylmethacrylate) duplicate of a laboratory high‐pressure reactor is set up to measure residence times and visualize flow lines. Experimental results are then compared to a computational fluid dynamics model. [ABSTRACT FROM AUTHOR]

The rheological behaviors of low-density polyethylene doped with additives (PEDA) determine the dynamic extrusion molding and structure of high-voltage cable insulation. However, the coupling effect of additives and molecular chain structure of LDPE on the rheological behaviors of PEDA is still unclear. Here, for the first time, the rheological behaviors of PEDA under uncross-linked conditions are revealed by experiment and simulation analysis, as well as rheology models. The rheology experiment and molecular simulation results indicate that additives can reduce the shear viscosity of PEDA, but the effect degree of different additives on rheological behaviors is determined by both chemical composition and topological structure. Combined with experiment analysis and the Doi–Edwards model, it demonstrates that the zero-shear viscosity is only determined by LDPE molecular chain structure. Nevertheless, different molecular chain structures of LDPE have different coupling effects with additives on the shear viscosity and non-Newtonian feature. Given this, the rheological behaviors of PEDA are predominant by the molecular chain structure of LDPE and are also affected by additives. This work can provide an important theoretical basis for the optimization and regulation of rheological behaviors of PEDA materials used for high-voltage cable insulation. [ABSTRACT FROM AUTHOR]

In the present work, direct incorporation of bioactive compounds onto the surface and interlayer of nanoclays before their incorporation into the final polymeric film was conducted, based on a green methodology developed by our group that is compatible with food packaging. This will lead to the higher thermal stability and the significant reduction of the loss of activity of the active ingredients during packaging configuration. On this basis, the essential oil (EO) components carvacrol (C), thymol (T) as well as olive leaf extract (OLE), which is used for the first time, were incorporated onto organo-modified montmorillonite (O) or inorganic bentonite (B) through the evaporation/adsorption method. The prepared bioactive nanocarriers were further mixed with low-density polyethylene (LDPE), via melt compounding, in order to prepare films for potential use as fresh fruit and vegetable packaging material. Characterization of the bioactive nanocarriers and films were performed through XRD, TGA, tensile, antimicrobial and antioxidant tests. Films with organically modified montmorillonite loaded with carvacrol (OC), thymol (OT) and olive leaf extract (OOLE) at 5% wt. showed better results in terms of mechanical properties. The films with polyethylene and organically modified montmorillonite loaded with carvacrol or thymol at 20% wt. (PE_OC20 and PE_OT20), as well as with olive leaf extract at 5 or 10 %wt., clay:bioactive substance ratio 1:0.5 and 10% compatibilizer (PE_OOLE5_MA10 and PE_OOLE10_MA10) exhibited the highest antioxidant activity. The resulting films displayed outstanding antimicrobial properties against Gram-negative Escherichia coli (E. coli) with the best results appearing in the films with 10% OC and OT. [ABSTRACT FROM AUTHOR]

In this study, some of the critical fundamental properties, which are holding importance in usage areas, of low-density polyethylene (LDPE) film were studied by embedding size-graded and polydopamine-coated halloysite nanotubes into the polymer matrix. This concept evaluated the importance of the well-dispersion of nanoparticles in the composite system and interfacial adhesion between nanofiller and polymer matrix on the degree of crystallinity and mechanical properties. For this purpose, halloysite nanotubes, coated with polydopamine and size graded afterward, were integrated into the LDPE matrix by the twin-screw extrusion process, following which, nanocomposite films were prepared by film-blown technique. Both effects of halloysite nanoparticles, having the polydopamine layer on their surface and size-graded, on properties such as mechanical strength, thermal feature, and degree of crystallinity, of those directly acting on the usage goals of LDPE-based films, were tested. [ABSTRACT FROM AUTHOR]

The excessive plastics production and its inappropriate disposal contribute to unprecedented pollution. Galleria mellonella larvae were chosen as the object of this work, in order to evaluate its ability to biodegrade two types of plastics most common in everyday life: polystyrene (PS) and low-density polyethylene (LDPE). This research is one of the few that use PS and LDPE as the sole carbon sources in the diet of G. mellonella. We studied how contact with larvae affected both types of plastic, covering morphological, physicochemical and mass loss levels. In this particular work, twenty-five larvae were placed inside glass containers in direct contact with the plastics and incubated in the dark at 28 °C. The results showed that PS had greater biodegradation, indicating 56.12% mass loss, while LDPE was 5.11% degraded. After 7.25 days of testing, the larvae survival rate was 60% for PS and 82% for LDPE. The contact with the larvae changed the material wettability, being more noticeable on the PS surface. The formation of new chemical groups indicated the existence of biodegradation processes in the PS sample, but in LDPE no new bands were observed. After 7.25 days, we evaluated larval survival and pupal formation after contact with PS and LPDE, but no significant differences were observed between the groups. No significant difference on the survival and pupa formation of larvae exposed to both types of plastic was found. We conclude that G. mellonella larvae can be a cost-effective and promising alternative to biodegrade PS and LDPE pieces in plastic waste environments. [ABSTRACT FROM AUTHOR]

An interfacial adhesion improvement between low-density polyethylene (LDPE) and aluminum (Al) foil is an important challenge in designing multilayered packaging (TetraPak packaging type) due to insufficient inherent adhesion between both untreated materials. Therefore, extra adhesive layers are often used. The hydrophobic character of LDPE is responsible for poor adhesion to Al and can result in delamination. This study deals with the comparative study of the bulk modification of LDPE with various commercially available adhesive promoters with different chemical compositions to increase LDPE's adhesive characteristics and ensure good adhesion in LDPE/Al laminates. A copolymer of ethylene and methacrylic acid; a terpolymer of ethylene, maleic anhydride, and acrylic ester; or maleated polyethylene (PE) were used as adhesive promoters, and their effect on adhesion improvement of LDPE to Al was investigated. The best adhesion improvement was observed in LDPE-modified samples with maleated PE, while 0.1 wt.% additive content significantly increased peel resistance (from zero to 105 N/m). An additional increase in additive content (0.5 wt.%) in LDPE led to stronger adhesion forces than the cohesion forces in Al foil. Adding 0.5 wt.% of maleated PE into LDPE improved the LDPE/Al laminates' adhesion and can be applied in multilayered lamination applications. [ABSTRACT FROM AUTHOR]

The rheological properties and processability at injection molding were studied for bisphenol-A polycarbonate (PC) that was modified by low-density polyethylene (LDPE) having a low shear viscosity. The LDPE addition significantly decreased the steady-state shear viscosity, especially in the high shear rate region. The decrease did not originate from slippage on the die wall but due to interfacial slippage between the PC and dispersed LDPE droplets that deformed to the flow direction to a great extent. As a result of the viscosity decrease, injection pressure largely decreased from 150 to 110 MPa with the addition only 5 wt.% of LDPE. The enhanced flowability also reduced the warpage of the molded product significantly, demonstrating that the processability at injection molding was improved by the addition of LDPE. [ABSTRACT FROM AUTHOR]

There is an increasing need to develop new polymer composites with improved properties compared to conventional pure polymer materials. This work aims to develop composites of low-density polyethylene (LDPE) and iron oxide hematite particles. For this purpose, different types of hematite particles with well-defined shapes and narrow size distributions were synthesized: HC2 sample with pseudocubic hematite particles of an average diameter of 1020 nm, HE1 sample with ellipsoidal hematite particles of an average diameter of 533 nm, and HS1 sample with spherical hematite particles of an average diameter of 168 nm. The mass fractions of hematite in the composites were 0.25%, 0.5%, and 1%. Prepared LDPE/hematite composites were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and diffuse reflectance ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. The mechanical and barrier properties were also studied. The obtained results showed that all prepared composites have improved properties compared to the pure LDPE, especially the composites with pseudocubic hematite particles of well-defined shapes. The results of this study indicate that LDPE/hematite composites can be promising materials for a wide range of applications, especially as packaging materials where improved thermal and mechanical properties as well as resistance to ultraviolet (UV) irradiation are required. [ABSTRACT FROM AUTHOR]

It is of significant concern that the buildup of non-biodegradable plastic waste in the environment may result in long-term issues with the environment, the economy and waste management. In this study, low-density polyethylene (LDPE) was compounded with different contents of poly(butylene succinate) (PBS) at 10–50 wt.%, to evaluate the potential of replacing commercial plastics with a biodegradable renewable polymer, PBS for packaging applications. The morphological, mechanical and thermal properties of the LDPE/PBS blends were examined in relation to the effect of polyethylene–graft–maleic anhydride (PE–g–MA) as a compatibilizer. LDPE/PBS/PE–g–MA blends were fabricated via the melt blending method using an internal mixer and then were compression molded into test samples. The presence of LDPE, PBS and PE–g–MA individually in the matrix for each blend presented physical interaction between the constituents, as shown by Fourier-transform infrared spectroscopy (FTIR). The morphology of LDPE/PBS/PE–g–MA blends showed improved compatibility and homogeneity between the LDPE matrix and PBS phase. Compatibilized LDPE/PBS blends showed an improvement in the tensile strength, with 5 phr of compatibilizer providing the optimal content. The thermal stability of LDPE/PBS blends decreased with higher PBS content and the thermal stability of compatibilized blends was higher in contrast to the uncompatibilized blends. Therefore, our research demonstrated that the partial substitution of LDPE with a biodegradable PBS and the incorporation of the PE–g–MA compatibilizer could develop an innovative blend with improved structural, mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

When designing products that are made of composite materials and that contain natural fillers, it is particularly important to consider the long-term exposure of these materials to caustic liquids and substances (concentrated acids, bases), and to ensure that these products meet strict requirements for reliability and operational safety. This study investigated the effects of different solvents on the mass, mechanical, thermal, surface, and structural properties of polymer composites containing natural fillers in the form of pumpkin seed hulls. Experiments were conducted using four different filler contents (5, 10, 15, and 20 wt%) and grain sizes ranging from 0.2 to 0.4 mm and 0.6 to 0.8 mm. Hybrid injection-moulded pieces were immersed in distilled water (H2O), 1% NaOH solution, acetone (C3H6O), and toluene (C7H8) for 84 days. After that, their mechanical and thermal properties as well as their structure geometries were analysed statistically. Changes in the properties of the tested composite materials were assessed depending on the solvent type, and the statistical significance of these changes were determined. The results showed that the nature of degradation depended on the applied solvent type. It was observed that the polymer matrix of the toluene-immersed samples absorbed the liquid to a significant extent first and then underwent a gradual degradation with time. In contrast, the samples immersed in water showed a slight increase in their mass. It was found that all tested properties of the composite samples deteriorated irrespective of the solvent type. [ABSTRACT FROM AUTHOR]

Nanoparticle incorporation in polymeric matrices to generate polymer nanocomposite with the intention of maximizing the "nano-effect" derived from the nanoparticles and minimizing the drawbacks of the polymer is an emerging field of research. In this study, low-density polyethylene (LDPE) was mixed with varying concentrations of montmorillonite (MMT) nanoclays to create a polymer nanocomposite with desirable characteristics. Composite sheets with nanoclays contents of (0, 1, 2, 3, and 4 wt%) were prepared for hardness, tensile-fractography, thermal conductivity, and tensile testing (elongation and stress-at-break). The results showed that, according to scanning electron microscope (SEM) study, LDPE has a low flexibility temperature and is prone to corrosion. For larger MMT filler loadings (>3% wt), tensile-fractography showed nanoclays particle micro-aggregation. The pure LDPE sample fracture's tensile-fractography showed plastic deformation. MMT/LDPE samples with 3% wt hard MMT filler have brittle fractures without appreciable plastic deformation. Thermal conductivity test results show that LDPE/MMT composite thermal conductivity decreased with increasing clay concentration. The thermal conductivity values were reduced from a value of 0.13 W/m.K to a value of 0.039 W/m.K when reinforced with 0% wt to 3% wt filler loading, respectively. With 4% wt filler loading, LDPE/MMT composites had the highest shore hardness at 47.4. Yet, tensile tests indicated that increasing clay content improved the composite's characteristics. At modest loading percentages (1-2 wt%), tensile results were excellent. Furthermore, the elongation at break of the unadulterated LDPE was reduced by 20% and 30% after introducing 1% wt and 2% wt of MMT as reinforcement additives, respectively. Hence, MMT clay can improve the mechanical properties and thermal insulation of LDPE polymer matrix. [ABSTRACT FROM AUTHOR]

In this study, natural rubber (NR) and low-density polyethylene (LDPE) were melt blended in a 2-roll mill to fabricate NR/LDPE composites with liquid natural rubber (LNR) and hematite (α-Fe2O3) as compatibilizer and filler respectively. The effects of liquid natural rubber (LNR) on the mechanical properties and morphology of NR/LDPE composites were investigated. NR/LDPE composites were prepared in three different compositions of 70/30, 50/50 and 30/70, with filler content at varying concentrations (3, 5 and 7 g) while LNR was kept at 10 g for the modified composites. Results obtained showed increment in the tensile strength, tensile modulus, compressive and flexural properties but with decrease in the elongation at break the α-Fe2O3 and LDPE contents increase. The modification of the composites with LNR further enhanced the mechanical properties. FTIR spectrum of LNR revealed a peak at 3395 cm-1 suggesting the hydroxyl (OH) end group attached to the LNR chain due to the photochemical degradation of NR to yield LNR. FTIR spectra of the selected composites showed the presence of iron oxide bond (Fe-O) at 571 cm-1, 467 cm-1 and 463 cm-1 due to the incorporation of α-Fe2O3 filler particles in the composites. SEM images showed improved matrix/filler interfacial adhesion induced by the LNR compatibilizer. [ABSTRACT FROM AUTHOR]

Canola meal is a low-value agricultural residue obtained after oil extraction from canola, the utilization of which requires further attention. On the other hand, plastic waste disposal is also another leading issue that creates severe environmental challenges. Supercritical water gasification is considered an environmentally friendly technology to produce hydrogen from plastic residues and organic wastes. This study deals with hydrothermal co-gasification of canola meal and plastic wastes (i.e., low-density polyethylene) while exploring the influence of temperature (375–525°C), residence time (15–60 min) and plastic-to-biomass ratio (0:100, 20:80, 50:50, 80:20 and 100:0) on hydrogen yield. Maximum hydrogen yield (8.1 mmol/g) and total gas yield (17.9 mmol/g) were obtained at optimal temperature and residence time of 525°C and 60 min, respectively. A change in the gas yield with variable plastic-to-biomass ratio showed synergistic effects between both feedstocks. The trend of catalytic performance towards improving hydrogen yield was in the following order: WO 3 –TiO 2 (18.5 mmol/g) > KOH (16.9 mmol/g) > TiO 2 (9.5 mmol/g) > ZrO 2 (7.8 mmol/g) > WO 3 –ZrO 2 (7.4 mmol/g). • Canola meal and plastic waste were co-gasified in supercritical water for H 2 production. • Synergistic effects occurred during co-gasification of canola meal and plastic waste. • Effects of temperature, reaction time and plastic-to-biomass ratio were studied. • WO 3 –TiO 2 catalyst improved H 2 yields and carbon gasification efficiency. • Aliphatics, aromatics and organic compounds were obtained as intermediate products. [ABSTRACT FROM AUTHOR]

Multi‐objective optimization (MOO) to produce low‐density polyethylene (LDPE) in a tubular reactor is performed for three different purposes, namely, maximizing the monomer exchange rate, lowering operational costs, and increasing the productivity. The ASPEN simulator is used to resolve optimization problems. Here, MOO of particle swamp optimization (MOPSO), non‐dominated sorting genetic algorithm (NSGA‐II), and a hybrid strategy of NSGA II‐MOPSO are employed as a model‐based optimization for LDPE production in a tubular reactor. The results demonstrated that the hybrid strategy of NSGA II‐MOPSO is the most effective MOO strategy. Using the hybrid strategy, the discovered solution set provides the utmost precision and diversity along the Pareto front. [ABSTRACT FROM AUTHOR]

Limited information exists on the occurrence of microplastics (MPs) in East African coastal waters. A 300 μm manta net was used to collect surface water from 8 sites in the regions Dar es Salaam (DES) and Zanzibar (ZZ) during low and high tides. DES had a higher (p < 0.05) abundance of MPs than ZZ. Fragments and fibers were the dominant MP types at all sites. The number of fibers was significantly higher (p = 0.002) in DES than in ZZ. MPs were more prevalent during high tide in both DES and ZZ. The MPs within the 2–5 mm size range were identified most often. White and blue MPs were the most common in study sites comprising 45% and 18% of the total MPs respectively. Three polymers polypropylene (PP) high-density polyethylene (HDPE) and low-density polyethylene (LDPE) were identified. The occurrence of MPs in nearshore waters of DES and ZZ is probably due to their proximity to industrial areas, poor solid waste management, and high population pressure. [ABSTRACT FROM AUTHOR]

Low‐density polyethylene (LDPE) nanocomposites containing magnesium oxide (MgO) nanoparticles are obtained by melt mixing. MgO nanoparticles ca. 29 ± 2 nm are synthesized by sol–gel and organically modified on the surface with oleic acid (Mod‐MgO), whose final concentration in the polymers is 3, 5, and 10 wt%. The presence of these nanoparticles did not affect the crystallization process of LDPE. However, Young's modulus increases with 10 wt% of Mod‐MgO nanoparticles, rendering higher reinforcement effects with an increase as high as 48%. This affects the elongation at break, which decreases ca. 57% compared to neat LDPE. The storage and loss modulus of the LDPE/MgO and LDPE/Mod‐MgO nanocomposites increases at room temperature and low temperatures (−150 to −50°C) compared to neat LDPE. SEM analysis showed that the organic modification of MgO nanoparticles improved their dispersion within the polymer matrix. Nanocomposites present antimicrobial properties against Escherichia coli, reaching an efficiency ca. 53%. [ABSTRACT FROM AUTHOR]

Carbonized and activated low‐density polyethylene (LDPE) is suggested as a carbon catalyst for vanadium redox flow battery (VRFB). This carbon catalyst has many surface oxygen functional groups and a large surface area, while such benefits are achieved through activation of carbonized LDPE. According to electrochemical analysis, this carbon catalyst doped graphite felt (GF) enhances the redox reactivity of vanadium ions. More specifically, peak current density and peak potential separation for redox reaction of vanadium ions are 96.0 and 22.1% more improved than those measured by bare GF, while charge transfer resistance for the redox reactions is also improved by use of the catalyst doped GF. When performance of VRFB using this catalyst doped GF is measured, energy efficiency is 39% more improved than that measured without the catalyst. Based on that, this is revealed that new LDPE‐based carbon catalyst is effective for performance improvement of VRFB. [ABSTRACT FROM AUTHOR]

Despite the enormous environmental damage caused by plastic waste, it makes up over one-third of globally produced plastics. Polyethylene (PE) wastes have low recycling but high production rates. Towards the construction of ionic solar cells from PE, the present work describes the loading of a bioactive photoacid phycocyanobilin (PCB) dye from the pigment of Spirulina blue–green algae (as a natural resource) on low-density polyethylene (LDPE) plastic film. Dyeing was confirmed by X-ray photoelectron spectroscopy (XPS). Upon excitation of the Soret-band (400 nm), the photoluminescence (PL) spectra of PCB in neat solvents revealed two prominent emission peaks at 450–550 and 600–700 nm. The first band assigned to bilirubin-like (PCBBR) species predominated the spectral profile in the highly rigid solvent glycerol and upon loading 0.45 % (w/w) of the dye on plastic. The photoluminescence excitation (PLE) spectra of PCB for the second region (Q-band) at 672 nm in the same solvents confirmed the ground state heterogenicity previously associated with the presence of PCBA (neutral), PCBB (cationic), and PCBC (anionic) conformers. Time-resolved photoluminescence (TRPL) measurements induced via excitation of all PCB species at 510 nm in methanol revealed three-lifetime components with τ1 = ~0.1 ns and τ2 = ~2 ns associated with PCBBR species and τ3 = ~5 ns pertinent to the long-living photoproduct X*. Decay-associated spectra (DAS) analysis of the photoluminescence transient spectra of the final dyed films in the solid-state confirmed the improved generation of the long-living photoproduct as manifested in a significant increase in the PL intensity (~100-fold) and lifetime value (~90 ns) in the Q-region upon loading 6.92 % (w/w) of the dye on plastic. The photoproduct species were presumably assigned to the deprotonated PCB species, suggesting improved ionic mobility. The potential implementation of the PCB-sensitized PE solid wastes for the fabrication of ionic solar cells is discussed. [ABSTRACT FROM AUTHOR]

The contact with ultraviolet rays coming from sunlight causes color changes and deterioration in the main chain structures of composites in outdoor applications and affects the physical and mechanical properties of composite materials negatively. Photodegradation can be slowed and the mechanical strength of composite structures can be improved with adding photostabilizers in polymer matrix production. In this study, we modified low-density polyethylene (LDPE) polymer with an amine light stabilizer (Chimassorb 944), a light absorbent (Tinuvin 326), and an antioxidant (Irganox 1010) and then reinforced with jute fabric (JF). We examined the effect of protective additives, which are used to reduce the harmful effects of sunlight, on JF-reinforced LDPE composites. The color change, physical, and mechanical properties of the composites were determined after 120- and 240-h accelerated aging processes. The results indicate that both the antioxidants and the amine light stabilizers were more effective photostabilizers for JF-reinforced LDPE composites than the absorbents. [ABSTRACT FROM AUTHOR]

To develop sensing materials, this study used cheap and readily available graphite, with decalin as solvent to disperse the graphite in low-density polyethylene (LDPE). Two methods of solvent removal (heat treatment at 100 °C and natural drying) were applied. Afterward, two kinds of composite LDPE/graphite films with different proportions of graphite were obtained. Different samples of the two films were compared in terms of the differences in appearance, thermal properties, and resistances. SEM showed that the appearance of heat-treated composite films presented a complete and smooth structure and good bendability relative to untreated films. Thermal gravimetric analysis and differential thermogravimetry showed that composite films with heat treatment had a higher thermal stability. Differential scanning calorimetry results showed that the melting points of the two composite films decreased with increasing graphite content. Finally, these composite films were used to measure the induced voltage values corresponding to changes in pH of different samples. The results showed that stable voltage values could not be obtained in the case of composite materials with very low conductivity, and that an appropriate amount of graphite mixed with LDPE could have better acid–base sensing properties. [ABSTRACT FROM AUTHOR]

The study of commercial low-density polyethylenes (LDPEs) has always focused on the effects of the molecular architecture of the polymer on its shear and extensional rheological properties due to their direct influence on manufacturability. However, the complex morphology of industrial-grade LDPEs also affects the crystallization kinetics and dynamic mechanical properties of the polymers, which are key to the processibility and applications. Therefore, a comprehensive investigation was conducted into the areas of crystallization kinetics, crystallinity, dynamic mechanical, and linear and non-linear shear rheological properties of two industrial-grade LDPEs to build a cohesive insight into the influence of morphology on these material properties. We further analyzed the steady-state and transient shear viscosity data obtained from the two LDPEs in comparison with constitutive model predictions using the hierarchical multi-mode molecular stress function (HMMSF) and found excellent agreement within experimental accuracy between predictions by the HMMSF model and shear stress as well as normal stress data of the LDPEs investigated. [ABSTRACT FROM AUTHOR]

Graphite lacquer was simply sprayed on glass and low-density polyethylene (LDPE) substrates to obtain large area films. Scanning Electron Microscopy (SEM) images, Raman spectra, X Ray Diffraction (XRD) spectra and current-voltage characteristics show that at room temperature, the as-deposited films on different substrates have similar morphological, structural and electrical properties. The morphological characterization reveals that the films are made of overlapped graphite platelets (GP), each composed of nanoplatelets with average sizes of a few tens of nanometers and about forty graphene layers. The thermoresistive properties of the GP films deposited on the different substrates and investigated in the temperature range from 20 to 120 °C show very different behaviors. For glass substrate, the resistance of the film decreases monotonically as a function of temperature by 7%; for LDPE substrate, the film resistance firstly increases more than one order of magnitude in the 20–100 °C range, then suddenly decreases to a temperature between 105 and 115 °C. These trends are related to the thermal expansion properties of the substrates and, for LDPE, also to the phase transitions occurring in the investigated temperature range, as evidenced by differential scanning calorimetry measurements. [ABSTRACT FROM AUTHOR]