Polyethylene Films Research Articles

Comparison study on low-density polyethylene film biodegradation potential of Achoria grisella and Galleria mellonella larvae

Aim: The current research investigates biodegradation of Low-Density Polyethylene (LDPE) facilitated with and without gut microbiota in Galleria mellonella and Achoria grisella. Methodology: A batch of 50 larvae of Galleria mellonella and Achoria grisella administered with antibiotics (A group) along with larvae not fed with antibiotics (WA group) were exposed to LDPE film. After biodegradation, the weight loss of degraded LDPE film, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis, and Gas Chromatography-Mass Spectroscopy analysis were performed to confirm the plastic biodegradation potential of selected insects. Results: In a and WA groups, the post-biodegradation for a selected species of wax moth exhibited weight loss of 2.763%, 0.789%, 5.403% and 1.481%, respectively. The SEM images revealed that both A and WA groups were capable of LDPE film disintegration. The FTIR of biodegraded film confirmed the deterioration of LDPE by indicating a change in the typical peaks of C−H and H−C−H bonds that points out the biodegradation of polyethylene.Further, the thermogravimetric analysis showed a substantial mass loss in the LDPE flakes consumed by the insects, demonstrating a decline in the thermal stabilities of disintegrated polymers. GC-MS of frass validated the presence of many component groups, including alkanes, alcohols, esters, ethers and acids, which confirmed the biodegradation of LDPE. Interpretation: Wax worms possess the capacity to biodegrade LDPE, independent of gut microbiota Key words: Achoria grisella, Antibiotic, Galleria mellonella, Low-density polyethylene

Optimization design of the portable cylindrical water injection multilayer neutron spectrometer

The currently widely used multi-sphere neutron spectrometers still have many drawbacks, including complex design and processing, the need for multiple moderating spheres, high costs, large volumes, and complicated measurement procedures. This work proposes the portable cylindrical water injection multilayer neutron spectrometer (CWNS) as a promising alternative based on water pumping injection. The structure of CWNS consists of a central thermal neutron detector and a surrounding 6-layer of coaxial cylindrical water bags with varying diameters. During non-measurement periods, this CWNS is convenient to carry due to the absence of the need to inject moderating water. To optimize the CWNS design, we employed FLUKA simulation software to study and refine various parameters, including the thickness of the water bag, the material composition of the water bag, and the parameters of the supporting column. We finally achieved an optimized design. Specifically, the water bag of the CWNS is constructed using a 0.3 mm thick polyethylene film. The supporting column for the water bag is made of aluminum, providing stability and support to the overall structure. These optimized design parameters determine the specific size and configuration of the CWNS. The CWNS offers the benefits of convenient carrying, simplified processing, cost-effectiveness, and straightforward measurement. It has a promising potential use for the directional neutron dose monitoring.

Biodegradable mulch films improve yield of winter potatoes through effects on soil properties and nutrients

Biodegradable mulch films are recognized as a promising substitute of polyethylene (PE) films to alleviate the “white pollution”. Biodegradable mulch films with optimum degradation rates increase crop yield even compared to PE films. However, the mechanisms underlying this yield-increasing effect remains elusive. In this study, three biodegradable film treatments (BFM1, BFM2 and BFM3) and one PE film treatment (PFM) were used to evaluate their effects on soil and winter potatoes, and a partial least squares path model (PLS-PM) was constructed to investigate their relationships. The degradation rates of films under different treatments were ranked as BFM3 > BFM2 >BFM1 > PFM, and presented distinctive effects on soil properties and nutrients, structure of soil bacterial community, and yield traits of winter potatoes. The PLS-PM showed that mulch treatments affected potato yield through effects on soil properties (soil water and temperature) and soil nutrients (TOC, DOC, TN and NO3--N). The disintegration of the biodegradable films decreased soil water content and temperature, and reduced the loss of soil nutrients in the topsoil at the later growth stage of winter potatoes compared to PE films. Additionally, the elevated content of soil TN and NO3--N under treatment BFM1 may play a key role in its yield-increasing effect on potatoes compared to treatments PFM and BFM2. Thus, biodegradable mulch films with proper degradation rates regulate soil TN and NO3--N through their effects on soil water and temperature, and subsequently improve the yield of winter potatoes compared to PE mulch films.

Aging rate, environmental risk and production efficiency of the low-density polyethylene (LDPE) films with contrasting thickness in irrigated region

Physical thickness of low-density polyethylene (LDPE) films might determine the release rate of phthalic acid esters (PAEs) & structural integrity and affect production efficiency. However, this critical issue is still unclear and little reported. Aging effects were evaluated in LDPE films with the thickness of 0.006, 0.008, 0.010 and 0.015 mm in a maize field of irrigation region. The Scanning electron microscope (SEM) results showed that the proportion of damaged area (Dam) to total area of LDPE films was massively lowered with increasing thickness after aging. The highest and lowest Dam was 32.2% and 3.5% in 0.006 and 0.015 mm films respectively. Also, the variations in peak intensity of asymmetric & symmetrical stretching vibrations (ASVI & SSVI) were detected using Fourier transform infrared spectrum (FTIR), indicating that the declines in peak intensity tended to be slower with thickness. Interestingly, the declines in physical integrity were tightly associated with increasing exhalation rate of PAEs. Average releasing rate of PAEs was 38.2%, 31.4%, 31.5% and 19.7% in LDPE films from 0.006 to 0.015 mm respectively. Critically, thicker film mulching can lead to greater soil water storage at plough layer (SWS-PL) and better thermal status, accordingly harvesting higher economic benefit. Therefore, LDPE film thickening may be a solution to reduce environmental risk but improve production efficiency in arid region.

The Role of Interchain Force and/or Chain Entanglement in the Melt Strength and Ductility of PLA-Based Materials.

As an eco-friendly material, PLA was a desirable alternative to polyethylene and polypropylene films due to its biodegradability. The preferable melt strength of PLA-based materials was a key factor in ensuring its processing using extrusion blow. This paper focuses on the influence of interchain force and/or chain entanglement on the melt strength and ductility of PLA-based materials in recent years. In addition, the preparation of PLA-based materials via physical blending or reactive processing was also summarized. The blending of PLA with a flexible heteropolymer, driven by the interchain force and/or chain entanglements, were characterized as a practicable method for toughening PLA-based materials. Also, the restructuring of PLA chains, by branching based on chain entanglement, was suitable for increasing chain entanglements in PLA matrix, yielding satisfactory melt strength and ductility. This review aims to elucidate the relationship between interchain forces and/or entanglement with the melt strength and ductility of PLA-based materials. An essential and systematic understanding of the tailoring melt strength and rheological properties of PLA by interchain forces and/or entanglement was apt to improve and perfect the processing technology of the extrusion blow, and consequently improve the tensile strength and toughness of PLA films.

Morphology of the coffee root system using polyethylene film

Morphology of the coffee root system using polyethylene film

ВЛИЯНИЕ ПОСТОЯННОГО ЭЛЕКТРИЧЕСКОГО ПОЛЯ НА СТРУКТУРУ И СВОЙСТВА ПЛЁНОК ХЛОРСУЛЬФИРОВАННОГО ПОЛИЭТИЛЕНА В ПРОЦЕССЕ ФОРМИРОВАНИЯ ИЗ РАСТВОРА

The article studies the features of structural formations and their influence on the properties of chlorosulfonated polyethylene (CSPE) films in the process of preparation from solutions in carbon tetrachloride under the action of a constant electric field. It is shown that films formed in a directed constant electric field have a higher electrical resistance and lower values of electrical capacity, heat capacity, and electrical loss tangent compared to films formed outside the field.

Investigation of mechanical and viscoelastic properties of Agave cantala fiber-reinforced green composites for structural applications

This study explored using cellulosic plant fibers as composite-reinforcing materials for structural applications. Specifically, a green composite material was created using Agave cantala fiber (ACF) and an epoxy matrix with weight fractions ranging from 30% to 60%. The laminates were fabricated using a compression molding technique, which involved alternating layers of resin and fibers on a flat mold. The fibers were uniformly aligned, and the resin was layered over them. The mold was then covered with polyethylene film to ensure that voids were minimized, and the mold was compressed for 12 h at ambient temperature. Four different samples were created by varying the fiber and resin weight percentages, with ACF30 containing 30% fiber and 70% resin, ACF40 containing 40% fiber and 60% resin, ACF50 containing 50% fiber and 50% resin, and ACF60 containing 60% fiber and 40% resin. The resulting composites were characterized to investigate their mechanical properties and it was found that the 40% ACF laminates had the maximum tensile, flexural, and compressive moduli and strengths. Additionally, viscoelastic characteristics were evaluated, and the 40% ACF composite demonstrated the highest storage and loss moduli. Scanning electron microscopy was also used to interpret the interface between the fibers and the matrix at the fracture surfaces. These findings suggest that cellulosic plant fibers have the potential as reinforcement materials for creating high-performance composites.

Coupling dynamics of respiration, gas exchange, and Pseudomonas fluorescens growth on fresh-cut cucumber (Cucumis sativus L.) in passive modified atmosphere packing

This study established microbial growth models for fresh-cut cucumber packaged with different O2 transmission rate (OTR) films. Biaxially oriented polyamide/low-density polyethylene (BOPA/LDPE) film (Ⅰ: OTR5, Ⅳ: OTR48) and polyethylene (PE) film (Ⅱ: OTR2058, Ⅲ: OTR3875) were used to construct a passive modified atmosphere packaging (MAP). Mathematic models have been established to account for dynamic variations in the O2/CO2 concentration and their impacts on Pseudomonas fluorescens growth. The coupling models included: 1) respiration models of cucumber and P. fluorescens based on Michaëlis-Menten equation, 2) coupling gas exchange models based on Fick’s law that contained models of P. fluorescens growth and respiration, 3) coupling microbial growth models contained respiration and gas exchange models. Coupling model with Baranyi function successfully fitted variations of O2/CO2 concentration and P. fluorescens growth in the two packaging. In addition, quality properties of packed fresh-cut cucumber were determined. The film Ⅳ (OTR48) as a high barrier film showed the highest inhibition of P. fluorescens growth, adequately retained its colour, firmness and total soluble solid (TSS) concentration in contrast to the PE films packaging. The constructed coupling models can be utilized for assessing the shelf life and microbial growth of fresh-cut vegetables with spoilage dominated by pseudomonads.

Plant biomass mediates the decomposition of polythene film-sourced pollutants in soil through plastisphere bacteria island effect

The polyethylene (PE) film mulching as a water conservation technology has been widely used in dryland agriculture, yet the long-term mulching has led to increasing accumulation of secondary pollutants in soils. The decomposition of PE film-sourced pollutants is directly associated with the enrichment of specific bacterial communities. We therefore hypothesized that plant biomass may act as an organic media to mediate the pollutant decomposition via reshaping bacterial communities. To validate this hypothesis, plant biomass (dried maize straw and living clover) was embedded at the underlying surface of PE film, to track the changes in the composition and function of bacterial communities in maize field across two years. The results indicated that both dry crop straw and alive clover massively promoted the α-diversity and abundance of dominant bacteria at plastisphere, relative to bulk soil. Bacterial communities tended to be clustered at plastisphere, forming the bacteria islands to enrich pollutant-degrading bacteria, such as Sphingobacterium, Arthrobacter and Paracoccus. As such, plastisphere bacteria islands substantially enhanced the degradation potential of chloroalkene and benzoate (p < 0.05). Simultaneously, bacterial network became stabilized and congregated at plastisphere, and markedly improved the abundance of plastisphere module hubs and connectors bacteria via stochastic process. Particularly, bacterial community composition and plastic film-sourced pollutants metabolism were evidently affected by soil pH, carbon and nitrogen sources that were mainly derived from the embedded biomass. To sum up, plant biomass embedding as a nature-based strategy (NbS) can positively mediate the decomposition of plastic-sourced pollutants through plastisphere bacteria island effects.

Deep Straw Burial Accelerates Straw Decomposition and Improves Soil Water Repellency

The continuous input, slow decomposition, and retention of straw can impede tillage and crop growth, and the decomposition process of the straw in soil is affected by its composition and the method of application. Experimental Station of Jilin Agricultural University, Changchun City, Jilin Province. The soil type was Argiudolls, the experimental field area was 30 m2, and the maize was planted continuously for 12 years without returning the straw to the field. There were four treatments: (1) control (CK), 10 g of straw was placed on the surface of a nylon mesh bag, and the nylon mesh bag was separated from the soil by polyethylene film without contacting with the soil; (2) straw mulching (CM), a nylon mesh bag with 10 g of straw was placed on the soil surface; (3) straw burying (CD), a nylon mesh bag with 10 g of straw was buried at a depth of 40 cm from the soil surface; (4) straw burying (CE), a nylon mesh bag with 40 cm of soil depth. Fifteen micro-zones were set up with a micro-zone area of 1 m2 and each micro-zone consisted of four treatments randomly grouped in three replicates per treatment. The on-site nylon bag burying trial started on 20 April 2021 and ended on 15 April 2022. Nylon bag and soil samples were collected on days 0, 30, 90, 180, 270, and 360. SOC, TN, straw component decomposition, and water droplet-soil contact angle were determined. Our results showed that the CE treatment increased soil organic carbon (SOC) and total nitrogen (TN) content compared to the CM and CD treatments. Compared with CK, straw decomposition rates increased by 13.3%, 30.8%, and 22.3% in the CM, CD, and CE treatments, respectively. Lignin decomposition rates increased by 7.8%, 27.3%, and 16.2%; cellulose decomposition rates increased by 14.6%, 35.4%, and 27.3%; and hemicellulose decomposition rates increased by 17.2%, 31.7% and 23.7% in the CD treatment, respectively. Compared with CK, the contact angle of droplets in the CD treatment was statistically significantly increased by 91.5% when the droplets remained on the soil surface for 5 s. The rate of decrease of droplet contact angle with time was statistically significantly decreased by 11.8%, and the penetration rate of droplets on the soil surface was slower. Overall, the CD treatment promoted straw decomposition and increased SWR compared to the CM and CE treatments. which are important attributes to enhance soil quality and improve soil structural stability.

Oil-Soluble Ultraviolet-Absorbing Carbon Dots Dispersed in Polyethylene Films as Antiaging Materials

Oil-Soluble Ultraviolet-Absorbing Carbon Dots Dispersed in Polyethylene Films as Antiaging Materials

Experimental and numerical study on the potential of a new radiative cooling paint boosted by SiO2 microparticles for energy saving

In this study, we prepared a radiative cooling paint by adding polymethylpentene to acrylic resin mixed with SiO2 microparticles. To improve the cooling performance of the radiative cooling paint, it was optimized based on Mie theory and Monte Carlo simulation to determine the optimal volume fraction of SiO2 microparticles, the mass fraction of polymethylpentene, and the thickness of the radiative cooling paint. Then, the cooling potential of the radiative cooling paint was analyzed in detail based on field experiments. Finally, the improvement of the radiative cooling paint over the existing materials was briefly discussed. The results showed that an emissivity in the atmospheric window of 0.91 and a reflectivity in the solar spectrum of 92% (backed with aluminum foil) can be achieved by the optimized radiative cooling paint. The temperature drops/average cooling powers are 1.5 °C/53.3 W/m2 during the nighttime and 5.2 °C/46.8 W/m2 under an average solar irradiance of 639.3 W/m2 during the daytime for the radiative cooling paint covered with a polyethylene film.

Facile fabrication of ultrastrong polyethylene nanocomposite films with low filler content via flow-driven graphene re-dispersion assisted crystallization

Fabrication of polymer films with superb mechanical properties is far from mature compared to that of fibers, hampering the further engineering applications of lightweight polymer materials. Herein, high density polyethylene (HDPE) films reinforced with re-dispersed or refined reduced graphene oxide (rGO) are prepared via a facile melt-stretching strategy. The incorporation of only 0.2 wt% rGO is demonstrated to endow the melt-stretched film (80× stretch ratio) with ultrahigh Young's modulus of 2.9 GPa and tensile strength of 162.2 MPa, which are comparable to many engineering plastics and also significantly superior to the existing HDPE/graphene composites. More importantly, these modulus and strength values are increased by 71 and 65% compared to the neat PE (80×), respectively, far more than the theoretical prediction with the mixing rule. Experimental characterizations indicate that the high-efficient mechanical enhancement is attributed to the strong synergy of melt stretching-driven crystallization and rGO re-dispersion or refinement in constructing the compact and robust shish-kebabs crystal network. Such microstructural characteristics greatly promote the load transfer along the covalently bonded molecular chains, and also from polymer to rigid fillers under loading. Furthermore, the excellent puncture resistance and thermo-mechanical properties of PE/rGO films have been demonstrated. This work provides a feasible way towards scalable manufacturing of high-performance polymer nanocomposite films from general plastics and carbonaceous nanomaterials.

Temperature-adaptive rooftop covering with synergetic modulation of solar and thermal radiation for maximal energy saving

The energy consumption for maintaining desired indoor temperature accounts for 20% of primary energy use worldwide. Passive rooftop modulation of solar/thermal radiation without external energy input has a great potential in building energy saving. However, existing passive rooftop modulation techniques failed to simultaneously modulate solar/thermal radiation in response to rooftop surface temperature which is closely related to the building thermal loads, leading to limited or even counter-productive overall energy saving. Here, we report the development of a surface temperature-adaptive rooftop covering with synergetic solar and thermal modulations. The covering, made of a scalable metalized polyethylene film, demonstrated excellent solar absorptance modulation (72.5%) and thermal emissivity modulation (79%) in response to its temperature change from 22°C (indoor heating setpoint) to 25°C (indoor cooling setpoint), and vice versa. Building energy simulations demonstrate that the proposed rooftop covering can achieve all-season energy savings across all climate regions.

Mathematical modeling of modified atmosphere package/LDPE film combination and its application to design breathing cylinders for extending the shelf life of green asparagus

BackgroundThe O2 levels in food packaging systems play an essential role in the deterioration of food quality and shelf life. Modified atmosphere packaging (MAP) supports the storage of fresh and processed foods by inhibiting chemical and physical changes while reducing the deterioration caused by microorganisms.Materials and methodsThis study established and validated the equations for the relationship between MAP formulation reagents, asparagus respiration, permeability of packaging film, and rates of O2 and CO2 mass transfer in which different interactions occur and affect each other.ResultsThe resulting atmosphere of packaging was determined to be the key to achieving the MAP benefits. The active MAP formulations developed in this study were combined with very-low-density polyethylene films to store green asparagus spears. During storage, the combined films effectively maintained the firmness of green asparagus spears, fiber, and vitamin C content, and outperformed the passive MAP and control groups. The above results confirm all the equations in the passive and active MAP systems established in this study.ConclusionsHence, maintaining the asparagus quality with an active MAP treatment will reduce economic loss and possibly provide new insights into applying active MAP retail packages to preserve fruits and vegetables in post-harvest shelf life.Graphical

Unique Raoultella species isolated from petroleum contaminated soil degrades polystyrene and polyethylene

Polyolefin plastics, such as polyethylene (PE) and polystyrene (PS), are the most widely used synthetic plastics in our daily life. However, the chemical structure of polyolefin plastics is composed of carbon-carbon (C-C) bonds, which is extremely stable and makes polyolefin plastics recalcitrant to degradation. The growing accumulation of plastic waste has caused serious environmental pollution and has become a global environmental concern. In this study, we isolated a unique Raoultella sp. DY2415 strain from petroleum-contaminated soil that can degrade PE and PS film. After 60 d of incubation with strain DY2415, the weight of the UV-irradiated PE (UVPE) film and PS film decreased by 8% and 2%, respectively. Apparent microbial colonization and holes on the surface of the films were observed by scanning electron microscopy (SEM). Furthermore, the Fourier transform infrared spectrometer (FTIR) results showed that new oxygen-containing functional groups such as -OH and -CO were introduced into the polyolefin molecular structure. Potential enzymes that may be involved in the biodegradation of polyolefin plastics were analyzed. These results demonstrate that Raoultella sp. DY2415 has the ability to degrade polyolefin plastics and provide a basis for further investigating the biodegradation mechanism.

Preparation and Characterization of a Biodegradable Film Using Irradiated Chitosan Incorporated with Lysozyme and Carrageenan and Its Application in Crayfish Preservation.

In this study, a composite film was prepared using irradiated chitosan, lysozyme, and carrageenan for crayfish preservation. First, the chitosan was degraded by gamma rays, with the best antimicrobial properties being found at 100 KGy. By using the response surface method, the components of the composite film were irradiated chitosan (CS) at 0.016 g/mL, lysozyme (LM) at 0.0015 g/mL, and carrageenan (CA) at 0.002 g/mL. When compared to the natural chitosan film, the Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results demonstrated that the chemical properties of the composite film did not change with the addition of LM and CA, while the physical and antibacterial properties increased, including tensile strength (16.87 → 20.28 N), hydrophobicity (67.9 → 86.3°), and oxygen permeability (31.66 → 24.31 m3·um/m2·day·kPa). Moreover, the antibacterial activity of the films increased with the addition of LM and CA, especially for Shewanella putrefaciens: the zone of inhibition (mm) of CS, CS/LM, and CS/LM/CA was 9.97 ± 0.29, 14.32 ± 0.31, and 14.78 ± 0.21, respectively. Finally, the CS/LM/CA film could preserve crayfish for 10 days at 4 °C, whereas the polyethylene (PE) film could only preserve them for 6 days. Moreover, the composite film was excellent at inhibiting oxidative deterioration (TBARS value: 2.12 mg/kg, day10) and keeping the texture of crayfish muscle. Overall, our results suggested that the CS/LM/CA composite film produced can be applied as a biodegradable film in aquatic product packaging.

Computer-aided discovery of a novel thermophilic laccase for low-density polyethylene degradation

Polyethylene (PE) and industrial dyes are recalcitrant pollutants calling for the development of sustainable solutions for their degradation. Laccases have been explored for removal of contaminants and pollutants, including dye decolorization and plastic degradation. Here, a novel thermophilic laccase from PE-degrading Lysinibaccillus fusiformis (LfLAC3) was identified through a computer-aided and activity-based screening. Biochemical studies of LfLAC3 indicated its high robustness and catalytic promiscuity. Dye decolorization experiments showed that LfLAC3 was able to degrade all the tested dyes with decolorization percentage from 39% to 70% without the use of a mediator. LfLAC3 was also demonstrated to degrade low-density polyethylene (LDPE) films after eight weeks of incubation with either crude cell lysate or purified enzyme. The formation of a variety of functional groups was detected using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Damage on the surfaces of PE films was observed via scanning electron microscopy (SEM). The potential catalytic mechanism of LfLAC3 was disclosed by structure and substrate-binding modes analysis. These findings demonstrated that LfLAC3 is a promiscuous enzyme that has promising potential for dye decolorization and PE degradation.

Cold Plasma Surface Modification of PLA and LDPE Polymer Plastics

Low-density polyethylene (LDPE) and polylactic acid (PLA) plastic films were subjected to modification using different plasma sources. Argon, nitrogen, air and oxygen were used as a gas phase throughout the process, and their impact on the material's surface properties was verified. The surface activation rate was measured via atomic force microscopy regarding the porosity factor and using the water contact angle technique. The last method – being feasible, agile and of high sensitivity to alternating physicochemical surface character – was utilised to verify the post-process stability of the modified surface. Those tests were performed extensively, up to 160 hours (contact angle) and 240 hours (atomic force microscopy).