Recycled Low Density Polyethylene Research Articles

Plastic Versus Bioplastic as Packaging for Sanitary Products: The Environmental Impacts Comparison

ABSTRACTPlastic or bioplastic? Which is the least impactful flexible packaging solution for the environment? In literature, few works try to answer this question, and most of them are focused on food packaging applications, comparing only polylactic acid (PLA) with polyethylene terephthalate (PET) or other virgin plastics. Besides these lacks in the literature, this work aims at contributing to the scientific knowledge, helping in the meanwhile packaging companies to choose the best solution also for hygienic and sanitary applications as far as the environmental impact is concerned. The study is focused on the life cycle assessment of four solutions made of maize starch, PLA and polybutylene adipate terephthalate (PBAT), low‐density polyethylene (LDPE) and a recycled LDPE (R‐LDPE). The functional unit was a flexible packaging containing 10 sanitary towels. Primary data were retrieved thanks to an Italian company, whereas secondary data were extracted from the Ecoinvent 3.7 database. The SimaPro 9.4 software has been used to calculate the global warming, water consumption, acidification and abiotic depletion of elements and fossil fuels of each packaging solution. The results show that the raw materials and packaging production are the most impactful phases during the life cycle of plastics and bioplastics packaging, if compared to the distribution phase, the auxiliary materials involved and the final disposal. Great benefits could be gained using recycled plastics, which allow to reduce the extraction of virgin materials and overall appear as the best solution from an environmental point of view to package also sanitary products.

Mechanical Characterization and Dynamic Mechanical Analysis of Recycled Low Density Polyethylene Filled Unsaturated Polyester Composite

Unsaturated polyester resin (UPR) is widely used as matrix in composite development; however, it has poor toughness property. To solve this problem, many researchers have used different tougheners to modify the resin, but the use of recycled low-density polyethylene (RLDPE) has not been explored. This work is aimed at modifying unsaturated polyester resin (UPR) with recycled low-density polyethylene (RLDPE) as a toughener and establishing the effects on the mechanical and dynamic mechanical performance of the RLDPE-filled polyester composite. Unsaturated polyester resin was modified with 1.18 mm RLDPE at different proportions of 1-4 wt%. Casting method was used for the production and the mechanical and dynamic mechanical analyses of the produced composite materials were carried out using ASTM standards. UPR modified with 1.5 wt% RLDPE exhibited the best impact than the un-modified UPR. The control (un-modified) sample had the highest flexural and tensile strength of 18 MPa and 14.02 MPa respectively which was about 26% and 25% higher than UPR modified with 1 wt% RLDPE. The Dynamic Mechanical Analysis (DMA) result showed that the composite does not depend strongly on the modifier loading as no regular pattern was observed for storage modulus, loss modulus and damping factor respectively.

Enhancing the physical properties of recycled low-density polyethylene and virgin low-density polyethylene blend using octanoate starch

Increasing global consumption of low-density polyethylene leads to more polymeric waste and challenges solid waste management. Therefore, the process of recycling or mixing recycled low-density polyethylene (RLDPE) with the same virgin low-density polyethylene (VLDPE) and enhancing the properties of this blend by adding different amounts of bioplastic such as Octanoate starch (OCST) is a good contribution to getting rid of plastic waste and obtaining new materials. This paper mixed the 20, 30 and 50 wt.% from RLDPE with VLDPE to determine the homogeneous blend. Also, 30, 40, and 50 wt. % from OCST were blended with homogeneous as a 20:80 RLDPE: VLDPE to obtain a new hybrid blend containing bioplastic. The scanning electron microscope (SEM) results showed the high surface roughness of the film RLDPE: VLDPE after adding the OCST. The tensile strength, elastic modulus, and hardness of the 20:80 RLDPE: VLDPE blend were 13.0 ± 1.467 MPa, 0.08 ± 0.016 MPa, and 42.3 ± 2.32 Shore A, while the tensile strength, elastic modulus, and hardness of the 12:48:40 RLDPE: VLDPE: OCST were 14.3 ± 1.626 MPa, 0.1 ± 0.032 MPa, and 50.1 ± 2.78 Shore A respectively. On the other hand, the Fourier-Transform Infrared (FTIR) indicated that the strong bands at 1746 cm−1, 2856 cm−1, and 2927 cm−1 indicated stretching deformation of the ester carbonyl group and the methyl and methylene groups of OCST with blend polymers, respectively. The thermal properties as melting point, heat energy consumption, and heat flow difference increased from 122.52 to 123.73°C, −389.41 to −144.43 (mJ), and −77.88 to −28.89 (J/g) when the OCST content increased from 20:80 RLDPE: VLDPE to 12:48:40 RLDPE: VLDPE: OCST. Thermal decomposition led to the formation of functional groups such as hydroxyl and carbonyl on LDPE baskets and an increase in the carbonyl index after adding OCST to the RLDPE: VLDPE blend. The best hybrid blend was 12:48:40 RLDPE: VLDPE: OCST.

Sustainable Asphalt Mixtures with Enhanced Water Resistance for Flood-Prone Regions Using Recycled LDPE and Carnauba-Soybean Oil Additive.

This manuscript presents a comprehensive study on the sustainable optimization of asphalt mixtures tailored for regions prone to flooding. The research addresses the challenges associated with water damage to asphalt pavements by incorporating innovative additives. The study centers on incorporating recycled Low-Density Polyethylene (LDPE) and a tailored Carnauba-Soybean Oil Additive, advancing asphalt mixtures with a Control mix, LDPE (5%) + Control, and LDPE (5%) + 3% Oil + Control. A critical aspect of the research involves subjecting these mixtures to 30 wetting and drying cycles, simulating the conditions prevalent in tropical flood-prone areas. The incorporation of innovative additives in asphalt mixtures has demonstrated significant improvements across various performance parameters. Tensile Strength Ratio (TSR) tests revealed enhanced tensile strength, with the LDPE (5%) + 3% Oil-modified mixture exhibiting an impressive TSR of 85.7%. Dynamic Modulus tests highlighted improved rutting resistance, showcasing a remarkable increase to 214 MPa in the LDPE (5%) with a 3% Oil-modified mixture. The Semi-Circular Bending (SCB) test demonstrated increased fracture resistance and energy absorption, particularly in the LDPE (5%) with 3% Oil-modified mixture. Hamburg Wheel-Tracking (HWT) tests indicated enhanced moisture resistance and superior rutting resistance at 20,000 cycles for the same mixture. Cantabro tests underscored improved aggregate shatter resistance, with the LDPE (5%) + 3% Oil-modified mixture exhibiting the lowest weight loss rate at 9.820%. Field tests provided real-world insights, with the LDPE (5%) + 3% Oil mixture displaying superior stability, a 61% reduction in deflection, and a 256% improvement in surface modulus over the control mixture. This research lays the groundwork for advancing the development of sustainable, high-performance road pavement materials, marking a significant stride towards resilient infrastructure in flood-prone areas.

Correlation of structure, rheological, thermal, mechanical, and optical properties in Low Density Polyethylene/Linear Low Density Polyethylene blends in the presence of recycled Low Density Polyethylene and Linear Low Density Polyethylene

AbstractPost‐industrial low‐density and linear low‐density polyethylene blown films are mechanically recycled for reutilizing in the production of blown films for packaging applications. This process enables the production of films with lower cost and similar properties while preserving the environment and lowering the amount of waste material disposed of. The mechanical recycling process results in the production of recycled pellets. This process includes chopping, washing, drying, and reprocessing. Mixtures of these recycled materials and their virgin form with various concentrations are shaped into blown films with inherent 70 and 30 wt% loadings for low‐density polyethylene and linear low‐density polyethylene components, respectively. Fourier transform infrared spectroscopy results of the recycled material show no contamination or chemical reaction with other materials. Gel permeation chromatography is carried out on the virgin and recycled low‐density polyethylene and linear low‐density polyethylene, and the results indicate the occurrence of chain session and crosslinking during the recycling process. The decline in the thermal properties of the samples, seen from the differential scanning calorimetry results, indicates the presence of crosslinks. The effect of structural changes caused by the recycling process on the rheological properties is studied. The miscibility of the blend components is evaluated by Cole–Cole plots and then further proved by Han and Van Gurp–Palman curves. Mechanical properties display an upturn following the presence of the crosslinkes. A decline in the optical properties in the films caused by the refraction of light by the crosslink structure in the film bulk and on the surface is evident.Highlights LDPE and LLDPE were recycled according to the circular economy approach Blown films containing virgin and recycled LDPE and LLDPE were produced Chain scission and crosslinking as a result of recycling were studied Rheological, thermal, mechanical, and optical properties were studied

Effect of thermal-oxidative and mechanical degradation of recycled LDPE on foaming

In this study, we investigated the effect of recycling process on the molecular structure, viscoelasticity and foaming behavior of low density polyethylene (LDPE). A series of LDPE samples with different recycling process was prepared by multiple extrusion using a twin-screw extruder. The molecular weight distribution (MWD) was characterized by gel permeation chromatography (GPC). Wider MWD indicated the generation of higher molecular weight products. Small-amplitude oscillation rheology showed reduced loss factors, indicating that the chain entanglement was more difficult to relax. Moreover, nonlinear viscoelasticity was investigated using elongational rheology and molecular stress function (MSF) model. The results showed a steeper strain hardening exhibited in recycled LDPE. The correlated parameter β in the MSF model indicated that the recycling did not significantly change the branches regularity in LDPE, while the increasing [Formula: see text], the other correlated parameter, indicated that the chain entanglement was enhanced, which was corresponded to the improvement of high molecular weight component. The foaming results revealed that the recycled LDPE had finer cellular structure and higher nucleation density. Moreover, despite adding PP and active CaCO3 to simulate the impurities, the foamability loss of these mixed samples was well restricted and still valuable. Recycled LDPE is instead better than its corresponding virgin one in foaming performance, exhibiting the application potential for further developments.

Influence of a biodegradable contaminant on the mechanical recycling of a low‐density polyethylene sample

AbstractMechanical recycling of oil‐derived polymers is certainly our best option to reduce pollution, save raw materials, and protect ourselves and the environment from the adverse effects of waste disposal. However, the presence of contaminants, including other types of plastics, that are mixed in during the recycling collection process or during the mechanical waste sorting stage could adversely affect the quality of the recycled product, leading to the recycling of a poor‐quality secondary material. In this work, the influence of a biodegradable contaminant on the mechanical recycling of a low‐density polyethylene (LDPE) sample was investigated by rheological (shear and non‐isothermal elongation) and mechanical analyses. The results showed that 2% of the contaminant is able to influence the rheological, shear, and isothermal elongation properties of recycled LDPE, while the results of the mechanical tests showed that after one extrusion cycle, the main tensile properties were not significantly affected by the presence of the contaminant, but after only two cycles of extrusions, some significant reduction in the final properties began to appear. In short, the presence of 2% of a biodegradable co‐polyester in a LDPE matrix gives rise to a more pronounced decay of the rheological and mechanical properties, but, after two extrusion steps, both rheological and mechanical properties seem still useful for the production of film.Highlights To what extent the contaminant affects the quality and usability of the recycled LDPE; The effects of contamination on the LDPE sample during the recycling process; Reduction in properties, compromising product quality; Compromised product quality after only two additional processing steps; Important implications for the recycling industry.

Novel composite membrane based on recycled low-density polyethylene-alumina used for vacuum membrane distillation

BackgroundPlastic materials have a significant impact on the entire environment. Very relevant ideas in different areas with the aim of enhancing these materials and making them effective in our daily lives. In this context, our work in this article by using plastic materials in the manufacture of hydrophobic membranes realized in our Laboratory LEEP Enig Gabes Tunisia, followed by various analyses. These membranes are made of a Recycled Low-Density Polyethylene polymer by means of the Thermal Induced Phase Separation (TIPS) method by using solvents such as Butyl Acetate, non-solvent Hexane with the addition of Alumina at different concentrations to increase porosity.ResultsHydrophobic membranes are coupled to the vacuum still to test their performance. An analytical study by FTIR was done. Contact angle, pore size, porosity, mechanical test, bubble point pressure, AFM and SEM analysis. The results revealed that the addition of alumina had an important role in improving the structure, properties and therefore the performance of the membrane.ConclusionsThe membrane already prepared admits according to the analyzes tested a good porosity, hydrophobicity.

Development of lignocellulosic-plastic composite from rice husk and polyethylene

As the demand for wood and wood-based resources keeps outstripping its regeneration, forests are depleting rapidly. To curtail this, it is imperative to shift towards the use of alternative raw materials such as agricultural residues. This study entails the development of lignocellulosic-plastic composites from Rice Husk (RH) and Recycled Low-Density Polyethylene (RLDPE) binder with the potential of augmenting the wood-based composites. Herein, RH was milled, graded into two particle sizes (2 mm and 4 mm), and mixed with RLDPE at two binder ratios (40 wt% and 50 wt%). The obtained composites were evaluated by density, water absorption (WA), thickness swelling (TSW), tensile strength (TS) and bending properties - modulus of elasticity (MOE) and modulus of rupture (MOR). In general, the increase of binder from 40% to 50% resulted in significant improvement of both physical and mechanical properties; while the increment of RH particle size showed slight differences in the properties. Composite with 50% binder content and 4 mm particle size was observed to have the best performance which conforms to the requirements for general-purpose application and door core application.

Agricultural-wasteSesamum indicum L./recycled-low density polyethylene bio-composites: Impact of gamma radiation on mechanical and thermal properties

Composites synthesized from natural waste and recycled plastic is quite a promising and interesting field for scientists and polymer industries. In the present study, bio-composites based on agriculture residue Sesamum indicum L. and recycled-low density polyethylene were synthesized by extrusion and injection molding technique at a fiber loading of 10–40 wt%. Additionally, 3% of maleic anhydride grafted low density polyethylene was used as a compatibilizer. The prepared composites were irradiated at 25 kGy, 75 kGy and 125 kGy doses of gamma rays. The effects of different fiber content and gamma doses on mechanical properties were studied statistically by Design Expert software. Response surface methodology was employed to depict the interaction among various factors and optimization was done by desirability index method. Findings indicated that composites having 30% Sesamum indicum L. irradiated at 125 kGy demonstrated best mechanical properties. A significant enhancement in tensile and flexural properties of irradiated composites can be explained effectively in terms of the cross-linking effect. The fiber–matrix adhesion and modifications in composite structure was characterized by fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and X-Ray diffraction (XRD) analysis. Furthermore, thermal stability of the composites was also found to be increased. In addition, gamma-irradiated composite exhibited the highest storage modulus and a decrease in mechanical loss factor was also observed.

A Simple Method to Convert Cellular Polymers into Auxetic Metamaterials

The objective of this study was to present a simple and environmentally friendly process combining low pressure (vacuum) and mechanical compression to convert low-density polyethylene (LDPE) foams into low-density foams (76–125 kg/m3) with negative tensile and compressive Poisson’s ratios (NPR). As a first step, four series of recycled LDPE foams (electronics packaging) with starting densities of 16, 21, 30 and 36 kg/m3 were used to determine the effect of different processing conditions including temperature and pressure. Based on the optimized conditions, the tensile and compressive Poisson ratios of the resulting auxetic foams reached −2.89 and −0.66, while the tensile and compressive modulus of the auxetic foams reached 40 kPa and 2.55 kPa, respectively. The foam structure of the samples was characterized via morphological analysis and was related to the mechanical properties before and after the treatment (i.e., foams with positive and negative Poisson’s ratios). The tensile and compressive properties (Young’s modulus, strain energy, energy dissipation and damping capacity) for these auxetic foams were also discussed and were shown to be highly improved. These auxetic foams can be applied in sports and military protective equipment. To the best of our knowledge, there is only one report on vacuum being used for the production of auxetic foams.

Evaluation of tensile strength of cattle horn reinforced RLDPE composite

ABSTRACT Investigating novel natural fiber (NF) in developing and producing advanced composite materials (ACMs) is becoming most recent research domain among the material’s scientists and engineers. This occurred as a result of serious and unavoidable request to switch over from synthetic fibers which are non-renewable, decomposable and recyclable at their end of life and likewise costly. Treated cattle horn fiber (TCHF) was employed in this study to reinforce water sachet plastic waste using compounding and compression method. The disposed water sachet plastics acted as the source of recycled low density polyethylene (RLDPE) used in the research. Likewise, the cattle horns were picked randomly, cleaned and machined into fibers with the lengths of 6mm, 12mm and 18mm and then modified with 0.1, 0.2 and 0.3 Normality of NaOH. Moreover, the proportions of matrix materials (RLDPE) were varied by 10% interval ranging from 70% to 90% and fiber loading from 10-30%. L-9 Taguchi array method was used to design and analyses the results in order to find the best combination of fiber length, fiber and matrix volume fraction, and proportion of NaOH that would give the optimum tensile strength. The result revealed that Sample with 0.1N, 6mm fiber length (CHFL) and 10% fiber loading (CHFV) has maximum tensile strength. This means that tensile property of cattle horn reinforced RLDPE did not depend on the higher fiber loading. Also NaOH contributed highest percent of 47.08% to the tensile strength while CHFV contributed 11.71% but tensile strength decreases with increment in fiber length. Keywords: cattle horn fiber; composite; plastic; recycling; and tensile strength

Measuring the circularity potential of recycled LDPE based on quantity and quality conservation - a functional requirement matrix approach

The Plastics Strategy passed by the European Union aims to ensure the reuse of ten million tons of recycled plastics in products by 2025. Discussions on how to achieve this target are usually mass-driven focusing on recycling quotas but neglecting quality targets. However, the circular economy aims to preserve resources at their highest possible value focusing on both mass and quality conservation, to close material loops in the long term. Therefore, changes in physical properties of recycled plastics compared to virgin plastics should be addressed, but measuring quality is a complex task. This article introduces a functional requirement matrix approach to assess mass and quality conservation using an indicator called circularity potential based on physical properties. The indicator is demonstrated in a case study on a non-food pouch made of low-density polyethylene (LDPE). Two samples from mechanical and dissolution recycling were examined in a laboratory and compared to virgin LDPE. We built on existing studies, but further introduced thermal and aesthetic requirements as well as established weighting and compliance parameters to address the complexity of quality conservation. The exemplary case study shows a circularity potential of 49% for recycled LDPE from dissolution recycling and 30% for mechanically recycled LDPE Mass and quality conservation are higher for dissolution than for mechanical recycling, but also rely on different waste streams that offer future research need. Further sensitivity analysis demonstrated the significance of weighting and compliance parameters. The provided approach is configurable for specific product applications and applicable in the context of life cycle assessments.

Powder production from recycled low-density polyethylene waste and doum palm nuts for light weight engineering application: A circular economy approach

The circular economy approach has been established as a possible solution to the increasing menace of hazardous waste materials. Despite the advances in science and technology, the world still struggles with the disposal and management of low-density polyethylene (LDPE) waste. This study presents the potential of recycled waste LDPE known as “pure water sachets” (PWS) and doum palm nut (DPN) as raw materials for lightweight structural engineering applications. Powder samples were produced from the different compositions of PWS and DPN heated in a controlled environment. The heating temperatures ranged from 250 to 350 o C while the holding time was 60, 90, and 120 minutes. The fixed mass of each powder sample was compacted into cylindrical pellets, only G and H samples had sufficient strength to be handled after compaction. Sample G is a compact from the powder with 40% DPN, 60% PWS, heated to 350 o C for 60 minutes while sample H is from the powder with 60% DPN and 40% PWS, heated to 350 o C for 90 minutes. The micrographs showed that sample G was more homogeneous than sample H and contained fewer voids. F-TIR analysis conducted on the samples shows C-H functional group at 2915 and 2845 cm -1 , 1460 cm -1 , and 700 cm -1 which is similar to low-density polyethylene. The X-ray diffraction analysis conducted on the fabricated samples shows that the doum palm nut sample had an amorphous feature while the samples G and H show a semi-crystalline feature. The sample G had a density of 1.0 g/cm 3 and a hardness value of 10.2 HV making it useful for Printed circuit board substrates. • This study is concerned with taking advantage of the vast amount of plastic and agro-waste and recycling to develop compatible powder for lightweight engineering applications e.g. printed circuit board substrates. Doum palm nut (DPN) and waste pure water sachet were processed into powder using different heating temperature regimes and different holding times. The chemical, mechanical and thermal behavior of the compacted powder was investigated.

On comparison of recycled LDPE and LDPE–bakelite composite based 3D printed patch antenna

In the past two decades number of studies have been reported on the use of thermoplastics as a substrate for 3D printed patch antennas. However, no work has been reported on the thermoplastic-thermosetting composite-based substrate for 3D printed patch antennas and their mechanical, morphological, rheological, and radiofrequency (RF) characterization for sensing applications. In this study low-density polyethylene (LDPE) and LDPE-5% bakelite (BAK) composite-based patch antenna (resonating frequency 2.45 GHz) were printed (for secondary recycling) on fused deposition modeling (FDM) setup. The RF characteristics were measured using a vector network analyzer (VNA). Ring resonator test was used for measuring the dielectric properties of substrates (which suggests that the dielectric constant ([Formula: see text]) and loss tangent ([Formula: see text]) for LDPE was 2.282 and 0.0045, whereas for LDPE-5%BAK the calculated [Formula: see text] and [Formula: see text] was 2.0663, 0.0051 respectively). This study highlights that for the LDPE-5%BAK composite there was a marginal increase in the size of the patch antenna; but this resulted in improved transmittance, gain, and return loss for typical sensor applications. As regards to printability of substrate, 5% BAK resulted in a melt flow index (MFI) of 9.96 g/10 min in contrast to 12.208 g/10 min for a neat LDPE sample. The selected LDPE-5%BAK composite resulted in peak strength (PS) and break strength (BS) of 16.08 MPa and 14.47 MPa (at 180 °C screw temperature, 110 rpm, and 11 kg load) while processing with a twin-screw extruder (TSE), which was observed better than the neat LDPE (PS 11.98 MPa, BS 10.79 MPa). The results were supported with porosity (%), surface roughness (Ra) analysis based upon scanning electron microscopy (SEM) and bond strength using attenuated total reflection (ATR) based Fourier transformed infrared (FTIR) analysis.

Recycled polyethylene/polycarbonate blends compatibilized with oxidized polyethylene/CaCO3

AbstractPolyethylene (PE) and polycarbonate (PC) are not thermodynamically miscible, and they tend to be phase‐separated during melt‐processing, because of significant incompatibility in structures and properties. Interestingly, minerals such as CaCO3 are used in PE‐based supermarket bags for improving surface characteristics. In this study, recycled low‐density polyethylene (LDPE) and PC resins are melt‐blended at 50/50 wt%, without and with oxidized polyethylene (OPE) as a compatibilizer. A parallel experiment is conducted with 50/50 blends of virgin LDPE and PC resins. Various characteristics such as tensile, viscoelastic, melt‐flow, and phase morphology of the materials are analyzed. The 50/50 blend of recycled LDPE/PC blend shows an average tensile strength of 15 MPa, which increases to 24 MPa on the addition of 5 wt% OPE, where total recycled content is 95 wt% including 15 wt% CaCO3. Notably, the presence of CaCO3‐based filler in recycled LDPE has a profound effect in improving the mechanical performance of the materials.

Highly promising recycled low-density polyethylene sheet adsorbents for uranium recovery from seawater

ABSTRACT Amidoximated absorbers based on recycled low-density polyethylene (LDPE) sheets (food packaging bags, breast milk storage bags and grocery bags) for uranium recovery from seawater were investigated. Simultaneous irradiation grafting by gamma ray was performed. A 40-µm thick LDPE sheet submerged in the acrylonitrile (AN): methacrylic acid (MAA) solution of 60: 40 v/v% with the optimal gamma ray dose of 40 kGy showed the highest cografting degree of 85.28% and the highest amidoxime group density of 4.38 mol/kg. The field study was performed along the coastal area of the Gulf of Thailand. After 56 days of soaking, the highest adsorption capacity reached 1.79 g-U/kg-adsorbent. The reusability study for up to 6 cycles revealed about 20% of the adsorption capacity remaining in the last cycle. The study demonstrated that recycled LDPE sheets can be utilized as a substrate to synthesize uranium absorbers. It showed an acceptable uranium loading with good reusability in natural seawater environment. This method of reusing discarded LDPE sheets also helps alleviate environmental issues of non-degradable plastic wastes.

A Fast and Automated Strategy for the Identification and Risk Assessment of Unknown Substances (IAS/NIAS) in Plastic Food Contact Materials by GC-Q-Orbitrap HRMS: Recycled LDPE as a Proof-of-Concept.

A fast and automated approach has been developed for the tentative identification and risk assessment of unknown substances in plastic food contact materials (FCM) by GC-Q-Orbitrap HRMS. The proposed approach combines GC-HRMS full scan data acquisition coupled to Compound Discoverer™ 3.2 software for automated data processing and compound identification. To perform the tentative identification of the detected features, a restrictive set of identification criteria was used, including matching with the NIST Mass Spectral Library, exact mass of annotated fragments, and retention index calculation. After the tentative identification, a risk assessment of the identified substances was performed by using the threshold of toxicological concern (TTC) approach. This strategy has been applied to recycled low-density polyethylene (LDPE), which could be used as FCM, as a proof-of-concept demonstration. In the analyzed sample, 374 features were detected, of which 83 were tentatively identified after examination of the identification criteria. Most of these were additives, such as plasticizers, used in a wide variety of plastic applications, oligomers of LDPE, and substances with chemical, industrial, or cosmetic applications. The risk assessment was performed and, according to the TTC approach, the obtained results showed that there was no risk associated with the release of the identified substances. However, complementary studies related to the toxicity of the unidentified substances and the potential mixture toxicity (cocktail effects) should be conducted in parallel using bioassays.

Exposure to leachates from post-consumer plastic and recycled rubber causes stress responses and mortality in a copepod Limnocalanus macrurus

Effects of household post-consumer plastics and tyre rubber on a Baltic Sea copepod Limnocalanus macrurus were assessed. Fragments of commercial recycled low-density polyethylene vegetable bags and rubber originating from recycled car tyres were incubated in seawater, and the copepods were exposed to the filtrate of the water. L. macrurus experienced erratic swimming behaviour and increased mortality in the filtrate of unwashed vegetable bags, containing elevated concentrations of alcohols, organic acids and copper. Responses of the antioxidant defence system (ADS) were recorded in copepods exposed to rubber treatments containing high concentrations of zinc. Significant responses in the ADS enzymes indicate that reactive oxygen species (ROS) formation was exceeding the detoxification capacity of the ADS which may further lead to prolonged state of oxidative stress. Observed effects of exposure on the biochemical level coincide with impaired swimming activity of the copepods, indicating possible irreversible cellular responses leading to behavioural changes and mortality.

Evaluating Modified Asphalt Binder Comprising Waste Paper Fiber and Recycled Low-Density Polyethylene

The main concept of using waste and recycled materials as modifiers for construction materials, is to improve their performance, keep the resources, and conserve the environment from pollution problems. This investigation is tended to evaluate the effect of using two different types of modifiers on the physical properties of asphalt binder. The modifiers are Recycled-Low-Density-Polyethylene (R-LDPE) polymer and waste-Paper Fiber (w-PF), they were mixed individually and collectively with neat asphalt binder. The first set of modified binders comprised neat binder with 3% R-LDPE alone, the second is comprised 0.3%, 0.5% and 0.7% of w-PF alone, while the third comprised collective modifiers of 3% R-LDPE and 0.3%, 0.5% and 0.7% w-PF. The influence of these modifiers on neat asphalt binder was evaluated in terms of penetration (Pen.), softening point (SP), penetration index (PI), ductility, rotational viscosity (RV), penetration aging index (PAI) and softening point index (SPI). The obtained results indicate that the utilization of modifiers helps in improving the physical properties of asphalt binders by different levels. the modification by collective modifiers leads to an increase SP, RV, PI, PAI, and SPI to 65%, 2 times, 1.044, 0.93, 2.5 respectively compared to neat bitumen. As well, leads to a decrease in both Pen. and ductility to the levels 45% and 79% respectively. This indicates that the use of waste and recycled modifiers especially in the combined form encourage the production of comparative modified asphalt binder.