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Only a small fraction of the global plastic waste is recycled, and the recycled materials are often of lower quality. For example, only 14% of the world's total plastic is recycled, with low‐density polyethylene (LDPE) accounting for only 4% of it. This study presents a novel approach to transforming waste LDPE into electrically conductive artificial graphite with high crystallinity using stabilization and graphitization processes. This method achieves a carbon yield of 89.4%, surpassing yields from conventional polymer precursors, such as polyacrylonitrile and polyamide. The resulting LDPE‐derived graphite (LGP) exhibits a high crystallinity and electrical conductivity, twice those of natural graphite and comparable to those of artificial graphite, which typically requires extensive heat treatment to prepare. LGP can be used in pastes and inks for advanced applications, such as 3D printing, flexible electrodes, heaters, and photothermal devices. Additionally, the high crystallinity of LGP enables the formation of larger graphene oxide (GO) with an average size of 4.1 ± 2.4 µm, because the larger crystalline domains in LGP facilitate the exfoliation process. The approach developed in this study contributes significantly to LDPE waste management and provides a pathway for the fabrication of valuable carbon materials for broad industrial applications. This study achieved high‐crystallinity graphite from low‐density polyethylene (LDPE) and LDPE products, offering 89.4% carbon yield. Enhanced conductivity and crystallinity support applications in electronics, 3D printing, and photothermal devices. Efficient graphene oxide production demonstrates LDPE‐derived graphite (LGP)'s value in various applications addressing environmental applications, addressing plastic waste challenges by transforming LDPE into valuable carbon materials.

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.

The ability of the bacterial degradation of low-density polyethylene (LDPE) waste by Lysinibacillus fusiformis isolated from hydrocarbon-contaminated soil was investigated in the present study. The potential of the bacterial isolate to utilize LDPE waste bags of two different thicknesses in a month as a sole carbon source in mineral salt media was assessed. Further, the effect of pretreatment by xylene on the bacterial degradation of LDPE waste bags (0.5 percent w/v) in 30 days was investigated. The isolated Lysinibacillus fusiformis was able to degrade 9.51 percent of LDPE with 30 μm thickness but able to degrade only 1.45 percent of LDPE having 50 μm thickness. The bacterial biomass was 1.77 times higher on LDPE- 30 μm containing media in comparison to LDPE- 50 μm. The xylene pretreatment of LDPE wastes enhanced the biodegradation efficiency of isolated Lysinibacillus fusiformis to 12.09 and 1.97 percent respectively in 30 μm and 50 μm thick LDPE bags. The xylene pre-treatment improved the bacterial growth on media with LDPE of both thicknesses. The adherence of bacterium on the surface of LDPE was found more on 50 μm thick xylene treated LDPE compared to its untreated LDPE than 30 μm thick LDPE films. The xylene pre-treatment of polyethylene waste had an additive effect on the biodegradation of waste LDPE films with a significant effect on thickness.

The effect of six halogen-free flame retardant (FR) formulations was investigated on the thermal stability of two low-density polyethylenes (LDPE) and one linear low-density polyethylene (LLDPE), by means of thermogravimetric analysis (TGA) under nitrogen and air atmosphere. The relative data were combined with flammability properties and the overall performance of the FRs was correlated with the type of branching in the polyethylene grades and to their processing behavior. The thermal degradation kinetics was further determined based on the Kissinger and Coats-Redfern methods. In terms of flammability, the addition of a triazine derivative and ammonium polyphosphate at a loading of 35 wt. %. was found to be the most efficient, leading to UL 94 V0 ranking in the case of the LDPE grade produced in an autoclave reactor.

Polyethylene (PE) is the most abundant synthetic, petroleum-based plastic materials produced globally, and one of the most resistant to biodegradation, resulting in massive accumulation in the environment. Although the microbial degradation of polyethylene has been reported, complete biodegradation of polyethylene has not been achieved, and rapid degradation of polyethylene under ambient conditions in the environment is still not feasible. Experiments reported in the literature suffer from a number of limitations, and conclusive evidence for the complete biodegradation of polyethylene by microorganisms has been elusive. These limitations include the lack of a working definition for the biodegradation of polyethylene that can lead to testable hypotheses, a non-uniform description of experimental conditions used, and variations in the type(s) of polyethylene used, leading to a profound limitation in our understanding of the processes and mechanisms involved in the microbial degradation of polyethylene. The objective of this review is to outline the challenges in polyethylene degradation experiments and clarify the parameters required to achieve polyethylene biodegradation. This review emphasizes the necessity of developing a biochemically-based definition for the biodegradation of polyethylene (and other synthetic plastics) to simplify the comparison of results of experiments focused for the microbial degradation of polyethylene.

The development of polyamide 6 (PA6) and linear low-density polyethylene (LLDPE) blends is of great technological interest, as they have the potential to combine the good mechanical and thermal properties of PA6 with the high impact properties and good processability of the LLDPE. However, these two polymers are chemically and structurally different and therefore immiscible, and in general incompatible. The objective of this study was to evaluate the effect of maleic anhydride-grafted linear low-density polyethylene (LLDPE- g -MA) as compatibilizer agent on rheological, thermal, mechanical and morphological properties of PA6/LLDPE blends. PA6/LLDPE blends with different contents of LLDPE (10, 20, 30, 40 and 50 wt%) and with the addition of LLDPE- g -MA (5 wt%) were prepared in a twin screw extruder and the thermal and mechanical analysis were performed. The addition of LLDPE- g -MA as compatibilizer agent resulted in a better distribution and dispersion of LLDPE in PA6 matrix and a significant improvement in mechanical and thermal properties. The addition of the compatibilizer agent increased 160% the impact strength for the 50/50 (PA6/LLDPE) blend.

In this study, four different plastic materials usually used in the agricultural sector (polystyrene film (PS), polyethylene terephthalate film (PET), low-density polyethylene film (LDPE) and linear low-density polyethylene film (LLDPE)) were subjected to different abiotic treatments, including photo-oxidation (ultraviolet and e-beam radiation) and thermochemical treatments, to enhance polymer degradation. The extensive use of these polymers leads to large amounts of plastic waste generation, including small plastic pieces, known as microplastics, which affect the quality of the agricultural environment, including soil fertility and quality. Therefore, polymer degradation strategies are needed to effectively reduce plastic waste to protect the agricultural sector. The degree of polymer degradation was assessed by the use of thermal and spectroscopic analyses, such as TGA and FTIR. In addition, efficiency, cost–benefits, and potential side-effects were also evaluated to propose the optimal degradation strategy to reduce plastic waste from the point of view of efficiency. The results obtained showed that the pre-treatments based on photo-oxidation (ultraviolet B and C and e-beam radiation) were more efficient and had a better cost–benefit for the degradation of the polymers studied in relation to the thermochemical treatments. Specifically, ultraviolet photo-oxidation worked well for PS and PET, requiring low energy and medium times. However, e-beam radiation was recommended for PE (LDPE and LLDPE) degradation, since high energy and long times were needed when ultraviolet energy was applied to this polymer. Furthermore, the overall efficiency of the plastic degradation of pre-treatments should be studied using a multicriteria approach, since FTIR assessments, in some cases, only consider oxidation processes on the plastic surface and do not show the potential integrity changes on the plastic probes.

Microplastics have recently become a major environmental issue due to their ubiquitous distribution, uncontrolled environmental occurrences, small sizes and long lifetimes. Actual remediation methods include filtration, incineration and advanced oxidation processes such as ozonation, but those methods require high energy or generate unwanted by-products. Here we tested the degradation of fragmented, low-density polyethylene (LDPE) microplastic residues, by visible light-induced heterogeneous photocatalysis activated by zinc oxide nanorods. The reaction was monitored using Fourier-transform infrared spectroscopy, dynamic mechanical analyser and optical imaging. Results show a 30% increase of the carbonyl index of residues, and an increase of brittleness accompanied by a large number of wrinkles, cracks and cavities on the surface. The degree of oxidation was directly proportional to the catalyst surface area. A mechanism for polyethylene degradation is proposed.

The excessive amount of global plastic produced over the past century, together with poor waste management, has raised concerns about environmental sustainability. Plastic recycling has become a practical approach for diminishing plastic waste and maintaining sustainability among plastic waste management methods. Chemical and mechanical recycling are the typical approaches to recycling plastic waste, with a simple process, low cost, environmentally friendly process, and potential profitability. Several plastic materials, such as polypropylene, polystyrene, polyvinyl chloride, high-density polyethylene, low-density polyethylene, and polyurethanes, can be recycled with chemical and mechanical recycling approaches. Nevertheless, due to plastic waste’s varying physical and chemical properties, plastic waste separation becomes a challenge. Hence, a reliable and effective plastic waste separation technology is critical for increasing plastic waste’s value and recycling rate. Integrating recycling and plastic waste separation technologies would be an efficient method for reducing the accumulation of environmental contaminants produced by plastic waste, especially in industrial uses. This review addresses recent advances in plastic waste recycling technology, mainly with chemical recycling. The article also discusses the current recycling technology for various plastic materials.

Low-density polyethylene (LDPE) waste generates an environmental impact. To achieve the most suitable option for their degradation, it is necessary to implement chemical, physical and biological treatments, as well as combining procedures. Best treatment was prognosticated by Plackett-Burman Experimental Design (PB), evaluating five factors with two levels (0.25 mM or 1.0 gL-1 glucose, 1.0 or 2.0 mM CuSO4, 0.1 or 0.2 mM ABTS [2, 20-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)], pH 4.5 ± 0.2 or 7.0 ± 0.2 and 30 or 90 day incubation), which was reproduced for 150 days. Therefore, PB identified a sequential treatment (plasma followed by fungus) for partial LDPE biodeterioration. Sheets were pretreated with glow discharge plasma (O2, 3.0 x 10(-2) mbar, 600 V, 6 min.), followed by Pleurotus ostreatus biodeterioration. Fungus growth, colonization percentage, and pigment generation followed. Laccase (Lac), manganese peroxidase (MnP) and lignin peroxidase (LiP) activities were appraised. Additionally, contact angle (CA), functional group presence and changes and carbonyl and vinyl indices (Fourier transformed infrared spectroscopy) were evaluated. LDPE surface changes were assessed by Young's modulus, yield strength, scanning electronic microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Plasma discharge increased hydrophilicity, decreasing CA by 76.57% and increasing surface roughness by 99.81%. P. ostreatus colonization was 88.72% in 150 days in comparison with untreated LDPE (45.55%). After this treatment carbonyl groups (C = O), C = C insaturations, high hydrophilicity CA (16 ± 4) °, and low surface roughness (7 ± 2) nm were observed. However, the highest Lac and LiP activities were detected after 30 days (Lac: 2.817 U Lac g-1 and LiP: 70.755 U LiP g-1). In addition, highest MnP activity was observed at day 120 (1.097 U MnP g-1) only for P. ostreatus treated LDPE. Plasma favored P. ostreatus adsorption, adherence, growth and colonization (88.72%), as well as partial LDPE biodeterioration, supported by increased hydrophilicity and presence of specific functional chemical groups. The approximate 27% changes in LDPE physical properties support its biodeterioration.