Low-density Polyethylene Films Research Articles

Biodegradation of low-density polyethylene film by two bacteria isolated from plastic debris in coastal beach

Low-density polyethylene (LDPE) conduces massive environmental accumulation due to its high production and recalcitrance to environment. In this study, We successfully enriched and isolated two strains, Nitratireductor sp. Z-1 and Gordonia sp. Z-2, from coastal plastic debris capable of degrading LDPE film. After a 30-day incubation at 30 ℃, strains Z-1 and Z-2 decreased the weight of branched-LDPE (BLDPE) film by 2.59 % and 10.27 % respectively. Furthermore, high temperature gel permeation chromatography (HT-GPC) analysis revealed molecular weight reductions of 7.69 % (Z-1) and 23.22 % (Z-2) in the BLDPE film. Scanning electron microscope (SEM) image showed the presence of microbial colonization and perforations on the film's surface. Fourier transform infrared spectroscopy (FTIR) analysis indicated novel functional groups, such as carbonyl and carbon-carbon double bonds in LDPE films. During LDPE degradation, both strains produced extracellular reactive oxygen species (ROS). GC-MS analysis revealed the degradation products included short-chain alkanes, alkanols, fatty acids, and esters. Genomic analysis identified numerous extracellular enzymes potentially involved in LDPE chain scission. A model was proposed suggesting a coordinated role between ROS and extracellular enzymes in the biodegradation of LDPE. This indicates strains Z-1 and Z-2 can degrade LDPE, providing a basis for deeper exploration of biodegradation mechanisms.

Plastic Litter Emits the Foraging Infochemical Dimethyl Sulfide after Submersion in Freshwater Rivers.

Plastic pollution is widespread throughout aquatic environments globally, with many organisms known to interact with and ingest plastic. In marine environments, microbial biofilms that form on plastic surfaces can produce the odorous compound dimethyl sulfide (DMS), which is a known foraging cue. This has been shown to increase the ingestion of plastic by some invertebrates and therefore act as a biological factor which influences the risks of plastic to marine ecosystems. In freshwater however, the production of DMS has been largely overlooked, despite the known sensitivity of some freshwater species to this compound. To address this gap, the present study analyzed the production of DMS by biofilms which formed on low-density polyethylene and polylactic acid films after 3 and 6 weeks of submersion in either a rural or an urban United Kingdom river. Using gas chromatography-mass spectrometry, the production of DMS by these biofilms was consistently identified. The amount of DMS produced varied significantly across river locations and materials, with surfaces in the urban river generally producing a stronger signal and plastics producing up to seven times more DMS than glass control surfaces. Analysis of biofilm weight and photosynthetic pigment content indicated differences in biofilm composition across conditions and suggested that DMS production was largely driven by nonphotosynthetic taxa. For the first time this work has documented the production of DMS by plastic litter after submersion in freshwater rivers. Further work is now needed to determine if, as seen in marine systems, this production of DMS can encourage the interaction of freshwater organisms with plastic litter and therefore operate as a biological risk factor in the impacts of plastic on freshwater environments. Environ Toxicol Chem 2024;00:1-12. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Development of Antifungal Packaging From Low‐Density Polyethylene With Essential Oil of Oregano and Potassium Sorbate

ABSTRACTAntimicrobial low‐density polyethylene (LDPE) films were developed by adding 0%, 0.5%, 1.0%, 2.5% and 5.0% (w/w) of Mexican oregano essential oil (OEO) or potassium sorbate (PS) as a positive antifungal control to inhibit the growth of Penicillium expansum, Penicillium citrinum and Aspergillus niger in vitro. Three methods of adding OEO in LDPE were evaluated; the best OEO yield in film was achieved when OEO was incorporated after laminating (88%); otherwise, when added into cool‐melting resin, OEO lost up to 91.5% from LDPE and completely volatilized (>99%) when combined with the resin before melting. PS yields in LDPE film were > 88% when incorporated into cool‐melted resin. Antimicrobial films with 2.5% or 5.0% (w/w) OEO or PS delayed the growth of P. expansum and P. citrinum for up to 4–5 days, and for A. niger, only films with 5.0% of OEO retarded its growth for 5 days. The modified Gompertz model was used to describe mould growth response, obtaining the parameters A (maximum growth), μm (maximum growth rate) and λ (lag phase), which correctly fit the data. P. citrinum was the most sensitive mould, and A. niger was the most resistant to the tested antimicrobials. The addition of antimicrobial agents significantly (p < 0.05) impacted the physical and mechanical properties of the LDPE films, wherein thickness and puncture strength were increased, and the colour changed (reducing the transparency and promoting the yellowness). In contrast, the water vapour transmission rate was dropped only by incorporating PS.

Visible-light driven photodegradation of low-density polyethylene (LDPE) using BiOCl–ZrO2 nanocomposite: A sustainable strategy for mitigating plastic pollution

This study aims to reduce plastic pollution by decomposing low-density polyethylene (LDPE) through an environmentally friendly approach using a novel BiOCl–ZrO2 nanocomposite under visible-light irradiation at room temperature. Visible-light irradiation is a form of clean energy, so we explored the feasibility and prospective solution for plastic waste mitigation by utilizing visible-light to attain sustainable development goal 7 (SDG 7). To fabricate photodegradable LDPE, it was blended with BiOCl nanoparticles (NPs) and its nanocomposite (BiOCl–ZrO2) separately via a facile solution casting method. The fabricated samples were assessed for the degradation of LDPE before and after 24 days of visible-light irradiation at room temperature. The prepared nanocomposites were thoroughly characterized by different analytical techniques, including XRD, FT–IR, XPS, FE–SEM, TGA, BET and UV–Vis DRS. The successful photodegradation of low-density polyethylene (LDPE) using a BiOCl–ZrO2 nanocomposite is supported by the presence of a higher carbonyl index, as evidenced by FT–IR analysis. The field-emission scanning electron microscopy (FE–SEM) analysis unveiled numerous perforations and prominent coarse morphological attributes, suggesting significant decomposition and disintegration of the LDPE film across the active surface sites of BiOCl–ZrO2. The weight reduction of LDPE@BiOCl–ZrO2 (600 ˚C) (10 wt%) composite film reached 48.67% under visible-light irradiation for 24 days at room temperature. The degradation rate exhibited significant sensitivity to variations in the concentration of the BiOCl–ZrO2 nanocomposite within the LDPE film. Investigation of the photodegradation mechanism suggested the formation of a type–II heterojunction–based photocatalytic system. The relatively low bandgap energy of ZrO2 (3.1 eV), facilitates the rapid migration of conduction band electrons to the conduction band of BiOCl. This migration process is facilitated by the favourable energy level alignment between the conduction bands of ZrO2 and BiOCl, enabling efficient electron transfer between the two materials. The large band gap of BiOCl (3.56 eV) permits the movement of valence band holes to the ZrO2 valance band. The spontaneous circulation of charge carriers within the heterostructure crystal maintains the charge separation and defers the recombination rate for an extended period. The photodegraded LDPE fragments are biodegradable and help to reduce plastic pollution. The environmental friendliness of the BiOCl–ZrO2 nanocomposite-assisted plastic waste remediation process was investigated using carbon footprint measurement. A tentative estimation suggested that the remediation process of 100 Kg of plastic waste may contribute to around 0.133 tons of carbon footprint.

Manufacturing process and annealing influence on the dynamic mechanical properties and physical structure of LLDPE thin films

Thin films of Linear Low-Density Polyethylene are used for stratospheric balloon applications. They undergo tensile mechanical stress on a wide range of temperatures [-95; 55]°C. The aim of this study is to compare the influence of blown film and double-bubble manufacturing processes on the crystalline phase and mechanical properties of the films through their operating temperatures (flight, storage, and transportation temperatures). Dynamic Mechanical Analysis and Differential Scanning Calorimetry have been used to monitor the dynamic mechanical properties in tension mode and the crystalline phase of the films respectively. The films mechanical properties are dependent on their manufacturing process. The double-bubble process allows isotropic tensile mechanical properties regarding stretching direction, whereas the blown film process favors only transversal direction. To simulate different storage conditions, annealing has been performed. The influence of annealing on the tensile mechanical properties of the films depends mainly on the internal stress stored during manufacturing. The double-bubble process produces a biaxially stretched film with a higher stretching ratio than blown films. The dissipated internal stress can be associated with thermal shrinkage and goes up to 10 % for the biaxially stretched film. The more internal stress is stored, the more E′ and E″ increases. Annealing also favors the formation of a secondary crystalline phase that is dependent on annealing temperature and time, and exhibits αc relaxation. After annealing, the amorphous phase is less stretched, and the crystalline phase keeps its orientation.

Biodegradation of low-density polyethylene film by Bacillus gaemokensis strain SSR01 isolated from the guts of earthworm.

In recent years, low-density polyethylene (LDPE) has emerged as an essential component of the routine tasks that people engage in on a daily basis. However, over use of it resulted in environmental buildup that contaminated aquatic habitats and human health. Biodegradation is the most effective way for controlling pollution caused by synthetic plastic waste in a sustainable manner. In the present study, the LDPE degrading bacterial strain was screened from gut of Earthworms collected from plastic waste dumped area Mettur dam, Salem district, Tamil Nadu, India. The LDPE degrading bacterial strain was screened and identified genotypically. The LDPE degrading Bacillus gaemokensis strain SSR01 was submitted in NCBI. The B. gaemokensis strain SSR01 bacterial isolate degraded LDPE film after 14days of incubation and demonstrated maximum weight loss of up to 4.98%. The study of deteriorated film using attenuated total reflection-Fourier transform infrared revealed the presence of a degraded product. The degradation of LDPE film by B. gaemokensis strain SSR01 was characterized by field-emission scanning electron microscopy analysis for surface alterations. The energy dispersive X-ray spectroscopy test confirmed that the broken-down LDPE film had basic carbon reduction. The present study of LDPE flim biodegradation by B. gaemokensis strain SSR01 has acted as a suitable candidate and will help in decreasing plastic waste.

Exploring the potential of earthworm gut bacteria for plastic degradation

The use of plastic mulch films in agriculture leads to the inevitable accumulation of plastic debris in soils. Here, we explored the potential of earthworm gut-inhabiting bacterial strains (Mycobacterium vanbaalenii (MV), Rhodococcus jostii (RJ), Streptomyces fulvissimus (SF), Bacillus simplex (BS), and Sporosarcina globispora (SG) to degrade plastic films (⌀ = 15 mm) made from commonly used polymers: low-density polyethylene film (LDPE-f), polylactic acid (PLA-f), polybutylene adipate terephthalate film (PBAT-f), and a commercial biodegradable mulch film, Bionov-B® (composed of Mater-Bi, a feedstock with PBAT, PLA and other chemical compounds). A 180-day experiment was conducted at room temperature (x̄ =19.4 °C) for different strain–plastic combinations under a low carbon media (0.1× tryptic soy broth). Results showed that the tested strain–plastic combinations did not facilitate the degradation of LDPE-f (treated with RJ and SF), PBAT-f (treated with BS and SG), and Bionov-B (treated with BS, MV, and SG). However, incubating PLA-f with SF triggered a reduction in the molecular weights and an increase in crystallinity. Therefore, we used PLA-f as model plastic to study the influence of temperature (“room temperature” & “30 °C”), carbon source (“carbon-free” & “low carbon supply”), and strain interactions (“single strains” & “strain mixtures”) on PLA degradation. SF and SF + RJ treatments significantly fostered PLA degradation under 30 °C in a low-carbon media. PLA-f did not show any degradation in carbon-free media treatments. The competition between different strains in the same system likely hindered the performance of PLA-degrading strains. A positive correlation between the final pH of culture media and PLA-f weight loss was observed, which might reflect the pH-dependent hydrolysis mechanism of PLA. Our results situate SF and its co-culture with RJ strains as possible accelerators of PLA degradation in temperatures below PLA glass transition temperature (Tg). Further studies are needed to test the bioremediation feasibility in soils.

Thin, disposable, antibacterial, heat-pressed photocatalytic plastic films

The production of several different thin, highly flexible, disposable, antibacterial, photocatalytic plastic films is described. A thin layer of a semiconductor photocatalyst, SC, powder is partially embedded in a thin (ca. 30 μm), highly flexible film of low-density polyethylene, LDPE, by heat-pressing the two together. The resulting SC/LDPE film is then tested for photocatalytic activity, via the photo-oxidised bleaching of methylene blue, MB, and photocatalysed antibacterial activity, via its inactivation of Escherichia coli, E. coli. The SCs tested include, P25 TiO2, high surface area Tronox rutile TiO2, low surface area rutile TiO2, ZnO and WO3. The MB test results reveal photocatalytic activities of the SC/LDPE films are, P25 TiO2 > ZnO > rutile TiO2 ≈ Tronox rutile TiO2 > WO3, which suggest the kinetics depend largely on the redox potential of the photogenerated conductance band electrons. In contrast, the E. coli deactivation results show that the order of activities of the SC/LDPE films, in the dark and (with an increased rate) upon illumination, are, Tronox rutile TiO2 > P25 TiO2 > ZnO > WO3 > rutile TiO2, which is similar to the variation in roughness factor, Rf. It appears that rough films are better at deactivating E. coli, not only under illumination, via both a photocatalytic and thermal mechanism, but also in the dark, via a ‘bed-of-nails’/shear stress physical mechanism. Encouragingly, in most cases, the photocatalysed antibacterial activity exhibited by the SC/LDPE films is not much (ca. 74 %) lower when a cool white fluorescent rather than UVA lamp is used (UVA irradiance = 47 μW/cm2 and 1.5 mW/cm2, respectively). The Tronox rutile TiO2 film was also found to be effective in deactivating another Gram-negative bacterium and, to a lesser extent, two Gram-positive bacterial species. The potential of these thin plastic films with a notable antibacterial activity under room light and in the dark is discussed briefly.

Synthesis of two TiO2-based prodegradant additives and their efficiency in inducing the accelerated photo-oxidation of low-density polyethylene

In this study, two prodegradant additives derived from TiO2 nanoparticles were synthesized and comprehensively characterized through a range of analytic techniques, such as X-ray diffraction (DRX), Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The hydroxyl groups adsorbed on the surface of TiO2 were esterified with biobased arachidonic acid (AA) and cervonic acid (DHA), resulting in levels of functionalization at 13 % and 16 % w/w, respectively. These additives were incorporated into low-density polyethylene (LDPE) films, at concentrations of 1 % and 3 % w/w. The prodegradant efficiency of the additives was subsequently assessed through accelerated UV aging. Following 200 h of exposure, the aged films experienced a loss in molecular weight (Mw) by approximately 95 %, accompanied by carbonyl indexes (CI) measuring 1.8 and 2.0. This high level of degradation observed in the LDPE films denotes an effective degradation mechanism, reliant on the generation of hydroxyl radicals by the TiO2 moiety, upon UV light exposure, and the subsequent abstraction of labile hydrogens within the polyunsaturated sidechain of the additives, resulting in the formation of peroxyl radicals, thereby initiating the swift auto-oxidation of the polyethylene films.

Biogenic silver nanoparticle-coated low density polyethylene film with antibacterial and antioxidant properties

Biogenic silver nanoparticle-coated low density polyethylene film with antibacterial and antioxidant properties

Microbial degradation of low-density polyethylene (LDPE) and polystyrene using Bacillus cereus (OR268710) isolated from plastic-polluted tropical coastal environment

The study focused on marine bacteria, specifically Bacillus cereus, sourced from heavily polluted coastal areas in Tamil Nadu, aiming to assess their efficacy in degrading low-density polyethylene (LDPE) and polystyrene over a 42-day period. When LDPE and polystyrene films were incubated with Bacillus cereus, they exhibited maximum weight losses of 4.13 ± 0.81 % and 14.13 ± 2.41 %, respectively. Notably, polystyrene exhibited a higher reduction rate (0.0036 day−1) and a shorter half-life (195.29 days). SEM images of the treated LDPE and polystyrene unveiled surface erosion with cracks. The energy dispersive X-ray (EDX) analysis revealed elevated carbon content and the presence of oxygen in the treated LDPE and polystyrene films. The ATR-FTIR spectra exhibited distinctive peaks corresponding to functional groups, with observable peak shifts in the treated films. Notable increases were detected in carbonyl, internal double bond, and vinyl indices across all treated groups. Additionally, both treated LDPE and polystyrene showed reduced crystallinity. This research sheds light on Bacillus cereus (OR268710) biodegradation capabilities, emphasizing its potential for eco-friendly waste management in coastal regions.

Effect of perforated low-density polyethylene films on postharvest quality of avocado fruit

Avocado (Persea americana Mill.) being a climacteric fruit, is very prone to quality deterioration and spoilage due to high metabolic activities which leads to postharvest and economic losses. The purpose of this study was to evaluate the impact of perforated low-density polyethylene (LDPE) packaging films on postharvest quality and shelf life of ‘Fuerte’ avocado. Fruit were packaged in LDPE plastics (20 and 40 μm) whereas unpackaged fruit were considered as control. Fruit were kept at ambient environments (21 ± 1 °C and 60.0 ± 5% RH) for 12 days and sampled at 4 days interval. The in-pack avocado created a suitable headspace with low O2 and high CO2 concentrations, which yielded improved preservation of postharvest quality and prolonged shelf life of the avocado. Fruit packed in both 20 and 40 μm LDPE films had lower ethylene production and respiration rates, weight loss, firmness loss, preserved fruit size, high pH, titratable acidity, low soluble solid content, sugar:acid ratio, malondialdehyde content and lipoxygenase activity compared to control. Fruit in LDPE films had no symptoms of decay (20 μm) and slight incidence and decay (40 μm) and were markable during shelf life compared to control fruit had severe decay symptoms and were unmarkable at the end of shelf life. These findings indicated that LDPE films were effective in preserving postharvest quality and extending shelf life of avocado fruit.

Biofilms on plastic litter in an urban river: Community composition and activity vary by substrate type.

In aquatic ecosystems, plastic litter is a substrate for biofilms. Biofilms on plastic and natural surfaces share similar composition and activity, with some differences due to factors such as porosity. In freshwaters, most studies have examined biofilms on benthic substrates, while little research has compared the activity and composition of biofilms on buoyant plastic and natural surfaces. Additionally, the influence of substrate size and successional stage on biofilm composition has not been commonly assessed. We incubated three plastics of distinct textures that are buoyant in rivers, low-density polyethylene (rigid; 1.7 mm thick), low-density polyethylene film (flexible; 0.0254 mm thick), and foamed polystyrene (brittle; 6.5 mm thick), as well as wood substrates (untreated oak veneer; 0.6 mm thick) in the Chicago River. Each material was incubated at three sizes (1, 7.5, and 15 cm2 ). Substrates were incubated at 2-10 cm depths and removed weekly for 6 weeks. On each substrate we measured chlorophyll concentration, biofilm biomass, respiration, and flux of nitrogen gas. We sequenced 16S and 23S rRNA genes at Weeks 1, 3, and 6 to capture biofilm community composition across successional stages. Chlorophyll, biomass, and N2 flux were similar across substrates, but respiration was greater on wood than plastics. Bacterial and algal richness and diversity were highest on foam and wood compared to polyethylene substrates. Bacterial biofilm community composition was distinct between wood and plastic substrates, while the algal community was distinct on wood and foam, which were different from each other and polyethylene substrates. These results indicate that polymer properties influence biofilm alpha and beta diversity, which may affect transport and distribution of plastic pollution and associated microbes, as well as biogeochemical processes in urban rivers. This study provides valuable insights into the effects of substrate on biofilm characteristics, and the ecological impacts of plastic pollution on urban rivers. PRACTITIONER POINTS: Plastic physical and chemical properties act as forces of selection for biofilm. Biofilm activity was similar among three different types of plastic. Community composition between plastic and wood was different.

Study of coating effectiveness of grape fruit seed extract incorporated Chitosan/cornstarch based active packaging film on grapes

The aim of the present study was to optimize the manufacturing process of grapefruit seed extract (GFSE) incorporated Chitosan (0.75 %, 2 % w/w) and various corn starch concentration of CHCS film of ratio 2:1, 1:1, 1:2 respectively using sorbitol as plasticizer. Optimization of chitosan concentration in chitosan corn starch film was done on the basis of physicochemical properties e.g. moisture content, film thickness, solubility, water vapour permeability and characterization of the films were done. It was reported that the films with CH: CS ratio 2:1 had tensile strength values comparable to that of other films with CH: CS ratio 1:1 and 1:2. Hence, films with 2 % (w/w) chitosan and CH: CS ratio 2:1 was found best among all the film samples shelf life extended to 20 days. GFSE incorporated film was found to have better anti-microbial properties as compared to commercial polypropylene (PP) and low density polyethylene (LDPE) films. GFSE incorporated CHCS film of ratio 2:1 was applied on Grape fruits. The antimicrobial effect of coating formulation on grape was mathematically calculated by predictive kinetic models and digital imaging. Sensory evaluation of applied coating formulation was found very efficient and confirmed the shelf life enhancement of 20 days.

The Concept of Using 2D Self-Assembly of Magnetic Nanoparticles for Bioassays

It can be observed that magnetic iron-oxide nanoparticles are increasingly used in bioassay methods. This is due to their stability in aqueous solutions, ease of functionalization, biocompatibility and very low toxicity. Here, we show that the recent discovery of the ability of magnetic nanoparticles to self-assemble into 2D structures of ordered chains may be exploited for bioassays. This would open up the possibility of controlled immobilization of proteins, enzymes, DNA or RNA and other molecular systems on spatially ordered nanostructures. In this work, fluorescein was used as an example. Also shown is the possibility of using Raman spectroscopy to analyze material accumulated on such structures. The observed formation of regularly spaced chains of magnetic nanoparticles takes place during the drying process of a thin layer of magnetic liquid placed on an appropriately prepared low-density polyethylene (LDPE) film.

Reactive extrusion of caffeic acid functionalized ε-polylysine with low-density polyethylene as an antimicrobial and antioxidant film

In this work, a novel grafted film with both antimicrobial and antioxidant properties was developed. ε-polylysine (EPL) and caffeic acid (CA) were used as raw materials, and EPL-CA was synthesized by grafting CA onto EPL by the carbodiimide coupling method. Using dicumyl peroxide (DCP) as a radical initiator, EPL-CA was crosslinked with low-density polyethylene (LDPE) by reactive co-extrusion to produce grafted films with both antimicrobial and antioxidant properties. Compared with pure LDPE film, all graft films show antimicrobial and antioxidant properties. Specifically, when the EPL-CA concentration is >3%, the inhibition rates against Escherichia coli (>91%) and Staphylococcus aureus (>97%) significantly increase, and the DPPH free radical scavenging rate (>60%) also significantly increases. Compared with the control film, the grafted film exhibits increased tensile strength and decreased elongation at break. In addition, the migration levels of all graft films in food simulants are below the migration standards set by the European Union. Overall, immobilizing EPL-CA on the LDPE matrix improves antimicrobial, antioxidant, and mechanical properties. Among them, the film exhibits the best comprehensive performance when the EPL-CA content is 3%. Therefore, the development of antimicrobial and antioxidant active LDPE film is proposed. These results indicate that active packaging films can be prepared through reactive extrusion, a promising and industrializable technology, and have broad prospects in improving food safety and other aspects.

Mechanical, Rheological, and Heat Seal Properties of 1‐Octene Grafted Low Density Polyethylene Films

AbstractHeat seal and mechanical properties of 1‐octene grafted low density polyethylene films containing various concentrations of Dicumyl peroxide as the initiator and 1‐octene grafting agent is investigated through using experimental measurements. The results of differential scanning calorimeter (DSC) measurements revealed that the melting temperature shifts to higher values and the peak of the DSC curve becomes wider with the increase of 1‐octene concentrations. Thermogravimetric analysis (TGA) revealed a higher thermal stability up to 20 °C for 1‐octene grafted PE compared with neat LDPE alloy. The results of stress–strain measurements revealed that the 1‐octene grafted PE alloys has higher tensile strength in comparison with neat PE alloy and samples containing only DCP initiator. The results of heat seal analysis indicated that both DCP initiator and 1‐octene tended to offer a moderate increase peel strength of PE alloy. DMTA measurements for various grafted PE alloys show a higher damping factor in comparison with neat LDPE alloy. Rheological measurements indicated a higher storage modulus up to 25% and higher complex viscosity for grafted PE samples containing 1‐octene comonomer.

The Influence of TiO2-Lignin Hybrid Fillers in Low-Density Polyethylene Composites on Photocatalytic Performance and UV-Barrier Properties.

The main objective of this study was to discover new packaging materials that could integrate one of the most expected properties, such as UV protection, with a self-cleaning ability defined as photocatalytic performance. Accordingly, new hybrid additives were used to transform LDPE films into materials with complex performance properties. In this study, titanium dioxide-lignin (TL) hybrid systems with a weight ratio of inorganic to organic precursors of 5-1, 1-1, and 1-5 were prepared using a mechanical method. The obtained materials and pristine components were characterized using measurement techniques and research methods, such as Fourier-transform infrared spectroscopy (FTIR), thermal stability analysis (TGA/DTG), measurement of the electrokinetic potential as a function of pH, scanning electron microscopy (SEM), and particle size distribution measurement. It was found that hydrogen bonds were formed between the organic and inorganic components, based on which the obtained systems were classified as class I hybrid materials. In the next step, inorganic-organic hybrid systems and pristine components were used as fillers for a low-density polyethylene (LDPE) composite, 5 and 10% by weight, in order to determine their impact on parameters such as tensile elongation at break. Polymer composites containing titanium dioxide in their matrix were then subjected to a test of photocatalytic properties, based on which it was found that all materials with TiO2 in their structure exhibit photocatalytic properties, whereby the best results were obtained for samples containing the TiO2-lignin hybrid system (1-1). The mechanical tests showed that the thin sheet films had a strong anisotropy due to chill-roll extrusion, ranging from 1.98 to 3.32. UV-Vis spectroscopy revealed four times higher light absorption for composites in which lignin was present than for pure LDPE, in the 250-450 nm range. On the other hand, the temperature at 5% and 30% weight loss revealed by TGA testing increased the highest performance for LDPE/TiO2 materials (by 20.4 °C and 8.7 °C, respectively).

Active Low-Density Polyethylene-Based Films by Incorporating α-Tocopherol in the Free State and Loaded in PLA Nanoparticles: A Comparative Study

In this work, alpha-tocopherol (α-TOC) was encapsulated in poly(lactic acid) nanoparticles (PLA NPs) and added to low-density polyethylene (LDPE) films with the aim of producing an active film for food packaging applications. PLA NPs loaded with α-TOC were produced through nanoprecipitation and dried using two methods (freeze-dryer and oven). LDPE-based films with final polymeric matrix concentrations of 10 and 20 g/kg were then produced through blow extrusion. The results showed that LDPE-based films loaded with α-TOC can be produced using blow extrusion, and a good distribution of PLA NPs can be obtained within the LDPE matrix as observed using scanning electron microscopy (SEM). The mechanical properties were affected by the incorporation of α-TOC and PLA NPs loaded with α-TOC, with the observation of a decrease in tensile strength and Young’s Modulus values and an increase in elongation at break. Regarding water vapor permeability, the films showed a reduction in the values with the addition of α-TOC and PLA NPs loaded with α-TOC compared to the LDPE film (control). Films with α-TOC in the free state and loaded in PLA NPs showed antioxidant activity, but their behavior was affected by the encapsulation process.

LLDPE film development surface with nucleating agents to reduce fat stains from food adherence on the film surface for easy rinsing before recycling

The purpose of this research was to enhance the surface of linear low-density polyethylene (LLDPE) film by using single and hybrid nucleating agents to reduce fat stains from food adherence on the film surface for easy rinsing before recycling, consequently reducing energy consumption before recycling. The process begins with the preparation of a high-concentration masterbatch of LLDPE with nucleating agents and polyethylene glycol (PEG), followed by blown film and test analysis. The results showed that both single and hybrid nucleating agents resulted in substantial modifications in the surface characteristics of the film. The altered surface texture of the film makes fat stains easy to remove. In addition, the use of hybrid nucleating agents resulted in considerable roughness on the film's surface. It can calculate the average roughness (Ra) from atomic force microscopy (AFM) images, which is very low at 4.7 nm, and the roughness is consistent. The contact angle was 99.17 degrees, and the percentage of crystallinity was clearly higher than that of a single nucleating agent. As a result, the fat stains on the film surface are easier to remove. The visual appearance, morphology, functional group, and mechanical properties of the films, on the other hand, were not significantly different. In summary, using a nucleating agent helped to rinse fat stains from the film easily.