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Melt strain hardening is a special feature of polymer materials and polymeric systems relevant for applications and fundamental insights into rheological properties. Strain hardening is dependent on the molecular structure of materials and deformation parameters. This paper deals with literature results of materials exhibiting strain hardening increasing with decreasing elongational rate opposite to most of common polymers. Such a behavior is found for ionomers and polymers with hydrogen bonding, and electrostatic molecular interactions are discussed as the physical origin. Furthermore, layered composites of non-strain hardening polymers are presented that can be rendered strain hardening by introducing compatibilizers or increasing the effect of interfacial tension between two layers by using multilayer arrangements. The strain hardening behavior of polypropylene/high density polyethylene blends of various compositions is discussed. Measurements on ethylene/α-olefin copolymers showing strain hardening significantly increasing with decreasing rate in contrast to linear ethylene homopolymers are described, and it is hypothesized that this behavior is due to a heterogeneous molecular structure with large differences of molar masses of the components. [ABSTRACT FROM AUTHOR]

The continuous raise of environmental issues by the polymer products has led to the use of eco-friendly basalt as a reinforcement for the composites fabrication. Basalt reinforcement has attractive qualities such as non-toxicity, ease of processing steps, economical, less harmful, and excellent thermal, and mechanical properties. Basalt loading into different polymer matrices is indeed a comparably novel concept that may offer some very intriguing views, which have not yet been fully explored. The ability of mineral fillers such as basalt powder to reduce the polymer portion in polymer goods by retaining their original characteristics hand out to the establishment of a pollution-free ecosystem and the stabilizing of ecological issues. In this context, the current research aims to manufacture and characterize thermoset (i.e., synthetic epoxy, bio-epoxy, unsaturated polyester, and vinyl ester) and thermoplastic (i.e., polylactic acid, bio-based polypropylene, and bio-based high density polyethylene) composites reinforced with the same weight content (i.e., 30%) of basalt powder. These composites were employed for physical, mechanical, wettability (contact angle analysis), morphological, and water absorption investigations. Moreover, basalt powder was subjected to elemental analysis (Energy dispersive X-ray), particle dimensional analysis, and morphological (Scanning Electron Microscopy) observations. The experimental results revealed that the tensile, flexural, and impact strength characteristics of composites were slightly reduced in comparison to neat polymers because of higher reinforcement. Besides, the tensile modulus, flexural modulus, and hardness values were gradually improved due to the filler effect. The increased water absorption is mainly caused by the voids inside of the composites, which create the quintessential environment for moisture to seep into the interface. Differential scanning calorimetry analysis reveals that the filler has successfully maintained the chain relaxation with the reduction of molecular movement and achieved stability as equivalent to a 100% polymer system, despite the incorporation of basalt by reducing the 30 wt% polymers. Except for synthetic epoxy composite, the remaining polymer composites have shown enhanced thermal conductivity values than neat polymers. However, the obtained findings can be considered satisfactory for prospective applications concerning lightness and environmental friendliness. [ABSTRACT FROM AUTHOR]

Plastic pollution is a critical environmental issue due to the widespread use of plastic materials and their long degradation time. Hydrocracking (HDC) offers a promising solution to manage plastic waste by converting it into valuable products, namely chemicals or fuels. This work aims to investigates the effect of catalyst accessibility and acidity on the HDC reaction of high density polyethylene (HDPE). Therefore, a variety of materials with significant differences in both textural and acidic properties were tested as catalysts. These include H-USY and H-ZSM.5 zeolites with various Si/Al molar ratios (H-USY: Si/Al = 2.9, 15, 30 and 40; H-ZSM-5: Si/Al = 11.5, 40, 500) and mesostructured MCM-41 materials modified with Ga and Al, also with different Si/metal ratios (Si/Al = 16 and 30; Si/Ga = 63 and 82). Thermogravimetric analysis under hydrogen atmosphere was used as a preliminary screening tool to evaluate the potential of the various catalysts for this application in terms of energy requirements. In addition, batch autoclave reactor experiments (T = 300 °C, PH2 = 20 bar, t = 60 min) were conducted to obtain further information on conversion, product yields and product distribution for the most promising systems. The results show that the catalytic performance in HDPE hydrocracking is determined by a balance between the acidity of the catalyst and its structural accessibility. Accordingly, for catalyst series where the structural and textural properties do not vary with the Si/Al ratio, there is a clear correlation of the HDPE degradation temperature and of the HDPE conversion with the Si/metal ratio (which relates to the acidic properties). In contrast, for catalyst series where the structural and textural properties vary with the Si/Al ratio, no consistent trend is observed and the catalytic performance is determined by a balance between the acidic and textural properties. The product distribution was also found to be influenced by the physical and chemical properties of the catalyst. Catalysts with strong acidity and smaller pores were observed to favor the formation of lighter hydrocarbons. In addition to the textural and acidic properties of the catalyst, the role of coke formation should not be neglected to ensure a comprehensive analysis of the catalytic performance. [ABSTRACT FROM AUTHOR]

The effects of 1.75 MeV N5+ ion beam irradiation of varying ion fluences, ranging from 1 × 1012 to 3 × 1014 ions/cm2, on high-density polyethylene have been done to investigate the structural, optical and chemical properties using X-ray diffraction (XRD), UV–visible spectroscopy and Fourier transform infrared (FTIR) spectroscopic techniques. XRD patterns show no significant change in crystallinity in irradiated polymer samples. The lattice plane and crystallite size of the irradiated polymer have not changed noticeably. More than 50% decrease in optical band gap were found for higher ion fluences of 3 × 1014 ions/cm2. UV–visible spectra show a red shift in absorption maxima due to the formation of extended conjugation. FTIR peaks 3646, 1707 and 2170 cm−1 in irradiated polymer were observed. The reaction mechanism chemistry of radiation-induced product formations, including chain scission, molecular crosslinking and hydroxyl, carbonyl and alkyne functional groups have been discussed. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are one of the major substantial pollutants in the environment and are stored in sediments worldwide, especially in marine environments. This study shed light on the abundance, distribution, sources and chemical composition of MPs present in the surface sediments collected from the shelf part of the southeast coast of India, Bay of Bengal. A total of twenty-seven surface sediment samples were collected to study MPs pollution. The abundance and morphological characteristics of MPs were determined by counting using an Olympus SXZ7 stereo microscope. Raman spectroscopy analysis was used to identify the polymer type of the MPs. The average abundance of MPs in the study area is 460±275 MPs/kg in dry sediment. Regarding colour, transparent particles were predominant (46.42%), followed by blue, green, brown, etc. With respect to particle shape and size, fibres and 500-µm sized MPs are abundant. Polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), high-density polyethylene (HDPE), low-density polyethylene (LDPE) and polystyrene (PS) are the polymer types characterised in the study area. The higher abundance of MPs in the study area can be attenuated to human interruptions, viz., tourism, fishing and inappropriate sewage disposal in the marine environment. In addition to this, population density also plays an important role in providing MPs to the marine environment. This study provides the most valuable data to extrapolate the research for mitigating MP pollution in oceans. It also informs mankind about their disastrous activities on the marine environment, which is expected to recuperate quickly and negatively impact human health and the functionality of the marine system. [ABSTRACT FROM AUTHOR]

The utilization of a mechanically stabilized earth wall (MSE wall) is prevalent due to its stability and cost-effectiveness compared to conventional earthwork construction methods. In addition, the railway transportation infrastructure has played a vital role in connecting Thailand's numerous regions. The behavior of a 6-m-high MSE wall constructed on a hard ground foundation, which was reinforced with high-density polyethylene on one side and a metallic strip on the other side, was studied in this research. The purpose of this MSE wall is to support the railway structure under dynamic train loads at 100, 150, and 200 km/h. The three-dimensional finite-element method was used to simulate and investigate the behavior of the MSE wall in terms of lateral displacement, settlement, and strain of reinforcement materials. The findings of the study demonstrate that there is a positive correlation between train speed and both lateral displacement and settlement. This relationship is most pronounced at the top of the MSE wall, which is primarily attributable to the influence of surface waves. The MSE wall's behavior under the influence of dynamic train loads was most prominently displayed by the surface waves, which were a curved wavefront at 150 km/h and a Mach cone at 200 km/h. The settlement profile increased when the speed of dynamic train loads increased. The impact of velocity fluctuations on the strain of the reinforcement material was insignificant. Due to the hard ground foundation, the behavior of the MSE wall on both types of reinforcement materials exhibited similar tendencies. Moreover, it was observed that the maximum tension lines closely follow the bilinear coherent gravity method with a standard distance of 0.3H from the facing, where H represents the equivalent height of the MSE wall. [ABSTRACT FROM AUTHOR]

Plastic recycling, waste minimization such as process outfall valorization promotes a circular economy. Herein, food trays have been produced in the moulded pulp thermoforming process. To this end, high-density polyethylene (HDPE) outfall has been dispersed in water via Poly vinyl alcohol (PVA) addition in a Northern Bleached Softwood Kraft Pulp (NBSKP) slurry. Samples physical and mechanical properties have been evaluated. With an increasing HDPE content, parts air permeability was drastically reduced to a minimum of 2.4 ± 0.8 mL min−1. In addition, water and grease hold out properties have been increased with minimum water Cobb1800 value of 10.9 ± 5.4 gm−2 and oil Cobb1800 value of 13.18 ± 6.5 gm−2. Samples with high HDPE content demonstrated hydrophobic surface with water contact angle value above 90°. HDPE melting and binding to wood pulp fibers was monitored by SEM images. Regarding the mechanical properties, HDPE induced plastic deformation with a reduced Young modulus by 17 %. Moreover, the addition of HDPE increased wet strength by 81 %. However, the produced food tray composites with high HDPE content demonstrated low repulpability index. [ABSTRACT FROM AUTHOR]

This study examines the mechanical properties of high-density polyethylene (HDPE) warp-knitted mesh fabrics under varying directional loads. Four distinct fabric structures have been produced using different lapping plans on a tricot warp knitting machine, with each structure tested under three directional loads (0°, 45°, and 90°). The findings show a significant improvement in breaking strength in the wales (0°) direction as compared to those in other fabric directions (45°, 90°) in all the fabric structures. Also, closed loop warp knit structure (S4) has greater bursting strength than the other samples due to its maximum stitch density. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High-density polyethylene (HDPE) pipes have gradually become the first choice for gas networks because of their excellent characteristics. As the use of pipes increases, there will unavoidably be a significant amount of waste generated when the pipes cease their operation life, which, if improperly handled, might result in major environmental contamination issues. In this study, the thermal degradation of polyethylene materials is simulated for different pressures (10, 50, 100, and 150 MPa) and temperatures (2300, 2500, 2700, and 2900 K) in the framework of Reactive Force Field (ReaxFF) molecular dynamics simulation. The main gas products, density, energy, and the mean square displacement with temperature and pressure are also calculated. The findings indicate that raising the temperature leads to an increase in the production of gas products, while changing the pressure has an impact on the direction in which the products are generated; the faster the temperature drops, the less dense the air; both temperature and pressure increase impact the system's energy conversion or distribution mechanism, changing the system's potential energy as well as its total energy; the rate at which molecules diffuse increases with temperature, and decreases with pressure. The results of this investigation provide a theoretical basis for the development of the pyrolytic treatment of polyethylene waste materials. [ABSTRACT FROM AUTHOR]

This research investigates the microbial degradation of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) plastics by Bacillus sp., Proteus sp., Pseudomonas sp., and Salmonella sp. The study employs a systematic approach, isolating microorganisms from plastic-contaminated soil and subjecting them to a series of biochemical tests for identification. The research evaluates the weight loss of LDPE and HDPE over two months, revealing varying degrees of degradation among the bacterial strains. Results suggest a potential greater susceptibility of HDPE to microbial degradation. Scanning Electron Microscopy (SEM) analysis provides high-resolution images of the plastic surface, indicating structural changes and biofilm formation during degradation. The findings highlight the unique enzymatic capabilities of each strain and underscore the significance of SEM in elucidating microbial interactions with plastics. The study prompts discussions on optimization, synergistic effects, and the identification of key enzymes in plastic degradation, emphasizing the importance of microbial strategies for waste management. Overall, this research contributes valuable insights into the potential of bacterial strains for addressing plastic pollution challenges. [ABSTRACT FROM AUTHOR]

Visualization and analysis of damage in honey peaches is important to reduce the occurrence of impact damage during postharvest handling. The finite element simulation method was used to visualize impact damage of honey peach. Firstly, the mechanical parameters such as maximum force, damage area, damage volume and absorbed energy during the collision between honey peaches and the surfaces of alloy steel, high density polyethylene (HDPE) and expandable polyethylene (EPE) were obtained by the collision device. Then, the elastic modulus and Poisson's ratio were obtained by compression tests of honey peach pulp. Finally, the process of collision between honey peaches and different material surfaces were simulated by finite element method. The results showed that the maximum error between the measured and simulated values of parameters were less than 25.1%. The study provides a reference for the selection of packaging materials for honey peaches and the biomechanical properties of various agricultural products. Practical applications: Impact damage is one of the most common mechanical injuries in postharvest handling of honey peaches, and it is of great significance to quantitatively study the impact damage of honey peaches to reduce the occurrence of impact damage of honey peaches during packaging and transportation. The study shows the feasibility of using the finite element method for quantitative prediction and assessment of impact damage in honey peaches. In addition, the selection of suitable packaging materials can be used to effectively reduce the occurrence of impact damage of honey peaches in the transportation process. The results of the study can not only provide theoretical support for the packaging and transportation of honey peaches and other aspects, but also provide a reference for the biomechanical properties of various agricultural products. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Floating breakwaters (FBs) are frequently used to protect marinas, fisheries, or other bodies of water subject to wave attacks of moderate intensity. New forms of FBs are frequently introduced and investigated in the literature as a consequence of technological advancements. In particular, a new possibility is offered by High-Density Polyethylene (HDPE) by extruding pipes of large diameters (e.g., 2.5 m in diameter) and with virtually no limit in length (hundreds of meters). By connecting two or three such pipes in a vertical layout, a novel low-cost floating breakwater with deep draft is devised. This note investigates numerically and experimentally the efficiency of this type of multi-cylindrical FBs in evaluating different geometries and aims at finding design guidelines. Due to the extraordinary length of the breakwater, the investigation is carried out in two dimensions. The 2D numerical model is based on the solution of the rigid body motion in the frequency domain, where the hydrodynamic forces are evaluated (thanks to a linear potential flow model), and the mooring forces do not include dynamic effects nor drag on the lines. The numerical predictions are compared to the results of a 1:10 scale experimental investigation. An atypical shape of the wave transmission ( k t ) curve is found, with a very low minimum in correspondence with the heave resonance frequency. The results essentially point out the influence of the position of the gravity center, the stiffness, and the mutual distance among cylinders on k t . [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are prevalent environmental pollutants due to their durable composition, extensive use, and improper disposal. Despite their widespread presence, rivers have received less attention in microplastic research than other water bodies. This study focused on investigating the origins, prevalence, spatial distribution, and physicochemical characteristics of microplastics in the surface waters of the Balu River, located in Dhaka, Bangladesh. Surface water samples were collected at six sampling sites of Balu River (each about 1–5 km apart) adjacent to the footwear industry, jute factory, textile mill, paper mill, agro and beverage factory, and cement plant. The study found that the average concentration of microplastics in the sampled water bodies was 102.5 ± 12.83 (items/l). Samples near the textile mill had the highest microplastic abundance (122 ± 18 items/l), while the cement plant had the lowest (58.5 ± 8 items/l). Analysis using a stereomicroscope revealed that fibers (29%), microplastics smaller than 100 µm (45%), and transparent microplastics (19%) were the most prevalent types observed in terms of shape, size, and color, respectively. Furthermore, scanning electron microscopy (SEM) observation suggested the potential for additional degradation of these microplastics into smaller particles, potentially reaching the nanoplastic scale. Additionally, Fourier transform infrared (FTIR) analysis identified 07 distinct polymer types among the microplastics: nylon (24%), polyvinyl chloride (19%), high-density polyethylene (17%), low-density polyethylene (14%), polystyrene (12%), polypropylene (7%), and nitrile (7%). The findings of this study serve as a crucial indicator of microplastic contamination, providing valuable insights into the sources and magnitude of microplastic pollution within the significant freshwater ecosystem of Balu River, Bangladesh, particularly focusing on its river systems. [ABSTRACT FROM AUTHOR]

Twenty types of polyethylene (PE) including high density polyethylene (HDPE) and linear low‐density polyethylene (LLDPE) with various viscosity were used to study the in‐situ formation of PE‐ ethylene propylene rubber (EPR) core‐shell rubber particles (CSRP) in polypropylene (PP) matrix by melt blending. The results show that PE and EPR cannot form CSRP if PE melt flow index (MFI) is lower than about 0.3 g/10 min. As a result, the impact fracture of PP/PE/EPR composite is brittle. If PE MFI is higher than 0.3 g/10 min, PE and EPR can form CSRP, leading to the ductile impact fracture of PP/PE/EPR composite. Interestingly, upper limit content of PE for the formation of CSRP depends on the type and viscosity of PE. For HDPE, upper limit content of PE tends to increase with the increase of its MFI, whereas it drops considerably for LLDPE. Understanding these relationships provides insights into optimizing the selection of core types and viscosity for enhancing the mechanical properties of polymer composites with core‐shell structure. This may potentially guide the development of cost‐effective and high‐performance polymer composites. [ABSTRACT FROM AUTHOR]

The recycling of waste plastics primarily involves physical modification and the addition of modifiers, often utilizing equipment such as twin‐screw extruders for miscible modification. Considering the widespread use of single‐screw 3D printing, improving the mixing efficiency of the single‐screw is crucial to achieve a "one‐stop" recycling modification that is suitable for 3D printing. This paper introduces a 3D printer equipped with a mixing screw (MS) and compares it with a conventional screw (CS). We conduct numerical simulations to investigate the pressure build‐up capacity, velocity streamline distribution, and the mixing effect of the MS. The mechanical properties, thermal characteristics, and molecular orientation of the recycled Polypropylene (rPP) and high density polyethylene (HDPE) mixture are investigated through experiments. The results show that the MS provides more effective elongational flows compared to the CS by breaking down the reinforcing materials into smaller particles. Additionally, toughening and modification experiments are performed on rPP and HDPE. The composites treated with the MS showed improved elongation at break (increased by ~111%), a stable melt crystallization temperature, and an enhanced mixing effect. This study on single‐screw 3D printers lays the groundwork for streamlining the plastic recycling process and increasing the reuse rate of recycled plastics. [ABSTRACT FROM AUTHOR]

Okra hessian cloth and Sunn hemp hessian cloth were prepared and treated with 5, 10, and 15 wt% alkali solutions for 1 h. The optimized concentration of alkali is 10 wt%. The untreated and treated hessian cloths reinforced high-density polyethylene (HDPE) composites were then prepared using the compression molding method. Alkali-treated, and 55 wt% fiber contents reinforced composites showed improved mechanical properties among 40, 45, 50, 55, 60, and 65 wt% fiber contents composites. 55 wt% fiber contents reinforced composites were then irradiated under gamma-ray at doses 2.5–7.5 kGy at the rate of 6 kGy/h. According to the X-ray diffraction analysis results, only alkali-treated Okra reinforced, and Sunn hemp-reinforced HDPE composites had higher crystallinity values than untreated and irradiated composites. Surface micrographs showed that the Okra-HDPE and Sunn hemp-HDPE had better matrix and fiber attachment. Cross-linking between the two varieties of fibers and matrix was seen using Fourier-transform infrared (FTIR) spectroscopy. Both irradiated composites exhibited greater hydrophobicity in their water intake characteristics compared to untreated and alkali-treated composites. The tensile strength (TS) value of Sunn hemp composite for 5 kGy gamma-ray irradiation dose is 68 MPa, which is 14% and 42% higher than that of treated and untreated composites, respectively. For comparison, the TS value for 5 kGy dose irradiated Okra composite is 66 MPa, which is 17% and 44% higher than that of treated and untreated composites, respectively. Young's modulus (Y) values of irradiated Okra composite and irradiated Sunn hemp composite showed higher values than that of other composites. Both irradiated composites have better thermal and structural characteristics than untreated and alkali-treated composites. [ABSTRACT FROM AUTHOR]

Bone tissue engineering (BTE) applications and regenerative strategies have been used to improve the clinical practice of repairing large bone defects associated with surgical resections, congenital malformations, and trauma. The scaffolds are designed to stimulate a biological response, including cell interactions, and guide tissue regeneration by functioning as artificial biomimetic extracellular matrixes. Polymeric biomaterials are suitable for bone tissue engineering since they possess both chemical and physical properties, enabling the control of shape, morphology, and biodegradability, which makes them suitable for bone regeneration and tissue engineering applications. In vivo animal models were studied for collagen, chitosan, poly (lactic acid) (PLA) and high density polyethylene (HDPE), the four most common polymers employed in bone tissue engineering. Through analysis of the results of this review, the in vivo studies can provide a large-scale evaluation of the possibility of achieving optimal bone-forming capabilities and regenerative capabilities. Furthermore, the review will serve as an essential reference for bone tissue engineering applications as well as contribute to the development of novel in vivo investigations [ABSTRACT FROM AUTHOR]

In this research, the performance of asphalt mixtures modified with polyethylene polymer (PE) by adding 2%, 4%, and 6% percentages was evaluated. Two kinds of PE are employed: Low-Density PE (LDPE) and High-Density PE (HDPE). The semi-wet mixing technique (SWM) was conducted to avoid stability issue for PE-modified binder during storage condition. Many experimental tests were conducted to evaluate the ability of these mixtures to withstand the effects of loads and moisture. The hardness index of these mixtures was also measured to determine their resistance to the effects of high temperatures without causing permanent deformations. The results showed that adding PE led to a remarkable enhancement in the performance of PE-modified mixtures. The improvement in stability reached 113.36% when using HDPE and it was 86.19% for LDPE. For moisture resistance, it improved by 10.42% and 9.91% when using HDPE and LDPE, respectively. The modified mixtures also showed higher hardness index compared to the standard mixture. According to the outcomes of this research, it can be concluded that the optimum percentage for using PE polymer as a modifier in bitumen is 6% and HDPE is more effective than LDPE. Overall, the SWM is easier and more economical compared to the wet mixing. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Engineering Transactions C: Aspects is the property of International Journal of Engineering (IJE) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigates the thermal performance of polymer-modified concrete composites, focusing on their potential to enhance energy efficiency in building envelopes. Four types of recycled polymers—low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (POLYP), and polyester—were integrated into concrete mixes at varying percentages (10%, 20%, and 30%). Key thermal metrics, including thermal transmittance (U-value), decrement factor (f), decrement delay (ϕ), admittance (Y), optimum thickness, and heat capacity per unit area, were measured using the admittance approach and a MATLAB program conforming to CIBSE standards. Results indicate that higher polymer content generally improves thermal damping and reduces cyclic transmittance. Notably, LDPE 30% exhibited the best performance, achieving a decrement factor of 0.179 and a time lag of 11.76 hours. HDPE 30% demonstrated a decrement factor of 0.206 and a time lag of 10.85 hours. Polyester 30% showed a decrement factor of 0.310 and a time lag of 8.50 hours. Sensitivity analysis revealed that optimal wall thicknesses for polymer-modified concretes are lower than those required for conventional concrete, with LDPE 30% requiring an optimal wall thickness of 0.128 meters compared to 0.269 meters for conventional concrete. This research underscores the dual benefits of waste management and energy performance improvement, advocating for the practical application of polymer-modified concrete in sustainable construction. The study ranks the polymers' efficiency as LDPE, HDPE, POLYP, and Polyester. These findings support the use of recycled polymers in concrete, promoting sustainability through effective waste management and improved thermal efficiency in building envelopes. [ABSTRACT FROM AUTHOR]

Amid the current environmental crisis caused by plastic accumulation, one of the proposed solutions to manage this problem is using biodegradable polymers. However, the impact of adding biodegradable polymers to the well-established circular economy of recyclable polymers, such as HDPE, has not been fully considered. Therefore, there is a need to reconsider the way we consume, dispose of, and manage biodegradable polymers after use. This study evaluates the effect of varying the contents of a biodegradable polymer, taking poly(lactic acid) (PLA) as a model biodegradable polymer, on the thermal and mechanical properties of HDPE. The study highlights the importance of identifying and disposing of biodegradable polymers to avoid mixtures with HDPE, in order not to affect mechanical performance when considering reprocessing and a new life cycle of this conventional polymer. [ABSTRACT FROM AUTHOR]

Additive manufacturing presents promising potential as a sustainable processing technology, notably through integrating post-consumer recycled polymers into production. This study investigated the recycling of high-density polyethylene (rHDPE) into 3D printing filament, achieved by the following optimal extrusion parameters: 180 °C temperature, 7 rpm speed, and 10% glass powder addition. The properties of the developed rHDPE filament were compared with those of commonly used FDM filaments such as acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) to benchmark the performance of rHDPE against well-established materials in the 3D printing industry, providing a practical perspective for potential users. The resulting filament boasted an average tensile strength of 25.52 MPa, slightly exceeding ABS (25.41 MPa) and comparable to PLA (28.55 MPa). Despite diameter fluctuations, the filament proved usable in 3D printing. Mechanical tests compared the rHPDE filament 3D printed objects with ABS and PLA, showing lower strength but exceptional ductility and flexibility, along with superior sound absorption. A life cycle analysis underscored the sustainability advantages of rHDPE, reducing environmental impact compared to conventional disposal methods. While rHDPE falls behind in mechanical strength against virgin filaments, its unique attributes and sustainability position it as a valuable option for 3D printing, showcasing recycled materials' potential in sustainable innovation. [ABSTRACT FROM AUTHOR]

Microplastics accumulate in the environment but methods to extract particles from sediment for quantification and identification often lack accuracy and reproducibility. Existing methods vary greatly and many do not achieve adequate microplastic separation. During method development for extraction procedures, spike-recovery experiments (positive controls) are essential to ensure accurate and reproducible results from each sample matrix. Furthermore, the large variability in grain size and organic matter can affect the extraction of microplastics from the matrix. Scientists have used density separation to separate microplastics from matrices for decades, but apparatuses are often made of plastic, need to be custom made, and require multiple sample transfers from one apparatus to another. This study presents an affordable, easily accessible, and simple to use Density Separation Device (DSD) to remove plastics from deep-sea sediments. Eight polymers were spiked into replicates of environmental sediment, including six fragments: high density polyethylene (HDPE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), nylon (PA6), and crumb rubber (CR) and two fibers: cellulose acetate (CA) and polyester (PEST). Two size classes of polymers were used: 100 μm to 300 μm and > 300 μm. Using a sodium polytungstate solution at a density of 1.9 g/mL and reflectance FTIR microscopy for particle identification, mean recoveries of all fragments exceeded 78% (CR: 92.7% ± 30.8%, PP: 78.4% ± 34.0%, HDPE: 93.8% ± 13.5%, PS: 86.9% ± 25.7%, PA6: 98.4% ± 63.2%, PVC: 100.0% ± 12.4%). Fiber recovery was much lower (PEST: 28.1% ± 28.1% and CA: 25.9% ± 17.3%) because they aggregated, passed through sieves vertically, or were obscured under other particles. The fragment recovery success, accessibility (available online, all parts under $200) and ease of use of this DSD should facilitate widespread use, thus helping to standardize sample preparation methods for microplastic metrology. [ABSTRACT FROM AUTHOR]

In pursuit of a sustainable future, the focus on thermoplastic compounding emerges as a transformative avenue. Strategically blending and compounding thermoplastics unlock the potential for eco-friendly materials, addressing pressing environmental concerns. Polymer blending is a widely utilized technique that offers significant advantages in terms of cost-effectiveness and the development of materials with diverse properties. However, achieving compatibility between polymers remains a challenge due to their non-negligible entropy, particularly in the case of immiscible polymers like Polypropylene (PP) and High-Density Polyethylene (HDPE). The success of such systems heavily depends on optimizing factors such as additive selection, mixing methodology, composition, and processing conditions. Despite the extensive industrial usage of polymers like PP and HDPE, there is still limited understanding regarding the impact of blending these polymers, especially when graphene is introduced. This study addresses these challenges by overcoming the entropy barrier between PP and HDPE using a high shear rate thermo-kinetic mixer and employing upcycled graphene nanoplatelets (GNP) as a type of low-cost graphene material through interface engineering. The GNP content in the blends ranged from 0 to 1 wt%, and through meticulous selection of the polymer weight fraction and the use of minimal GNP content, GNP was strategically localized at the blend interface. This resulted in remarkable mechanical performance achieved through the optimized manufacturing technique. Incorporating 0.1 wt% GNP resulted in a significant 38% increase in tensile modulus, while flexural modulus and flexural strength saw respective increments of 39% and 22% compared to neat PP. Further enhancements were observed with higher GNP contents. This study illuminates the transformative potential of thermoplastic compounding as a key driver toward a sustainable future. [ABSTRACT FROM AUTHOR]

Aims This study aimed to investigate the effect of Oliveria decumbens essential oil (Od- EO) on the phenotypic properties and gene expression of Staphylococcus aureus biofilm on commonly used food contact surfaces. Methods and results The minimum inhibitory concentration and minimum bactericidal concentration of Od-EO on S. aureus ATCC25923 were determined to be 0.5 and 1 µl/ml, respectively. Crystal violet staining, scanning electron microscopy (SEM), biofilm metabolic activity evaluation, and real-time PCR analysis were used to assess the anti-biofilm properties of Od- EO. The results demonstrated that Od- EO exhibited significant anti-biofilm properties against S. aureus and effectively reduced the metabolic activity of biofilm cells. Furthermore, the inhibitory effects of Od- EO on biofilm formation were more pronounced on stainless steel (SS) compared to high-density polyethylene (HDPE) surfaces. Real-time PCR analysis revealed that Od- EO downregulated the expression of biofilm-related genes (icaA, icaD, clfA, clfB, FnbA, FnbB , and hld) in S. aureus grown on SS, while the expression levels of all studied genes except hld in the biofilm formed on HDPE remained unchanged or increased. Conclusions One of the main anti-biofilm mechanisms of the Od-EO on the HDPE is related to the disturbance in the QS of the cells. These findings highlight the potential of Od- EO as an effective agent for controlling and inhibiting S. aureus biofilm in the food industry and its potential use in disinfectant compounds. [ABSTRACT FROM AUTHOR]

Aims This research aimed to analyze cutting board surfaces in seafood markets to find Vibrio parahaemolyticus , assess the isolates' ability to form biofilms, generate and evaluate characteristics of plasma-activated water (PAW), and compare the effect of PAW on planktonic and biofilm cells of the isolated V. parahaemolyticus strains. Methods and results A total of 11 V. parahaemolyticus strains were isolated from 8.87% of the examined cutting boards. Biofilm-forming ability was evaluated for these isolates at temperatures of 10°C, 20°C, and 30°C using crystal violet staining. Four strains with the highest biofilm potential were selected for further analysis. The pH of the PAW used in the study was 3.41 ± 0.04, and the initial concentrations of hydrogen peroxide, nitrate, and nitrite were 108 ± 9.6, 742 ± 61, and 36.3 ± 2.9 µM, respectively. However, these concentrations decreased significantly within 3–4 days during storage at room temperature. PAW exhibited significant antimicrobial effects on V. parahaemolyticus planktonic cells, reducing viable bacteria up to 4.54 log CFU/ml within 20 min. PAW also reduced the number of biofilm cells on stainless steel (up to 3.55 log CFU/cm2) and high-density polyethylene (up to 3.06 log CFU/cm2) surfaces, although to a lesser extent than planktonic cells. Conclusions PAW exhibited significant antibacterial activity against V. parahaemolyticus cells, although its antibacterial properties diminished over time. Furthermore, the antibacterial activity of PAW against biofilm cells of V. parahaemolyticus was less pronounced compared to the planktonic cells. Therefore, the actual effectiveness of PAW in seafood processing environments can be affected by biofilms that may form on various surfaces such as cutting boards if they are not cleaned properly. [ABSTRACT FROM AUTHOR]

The correlation between the single-point notched constant tensile load-stress crack resistance (SP-NCTL SCR) Test (ASTM D5397; Appendix) of smooth high density polyethylene (HDPE) geomembranes and their strain hardening modulus is investigated for both unaged and aged specimens. The strain hardening modulus was calculated based on the (force-elongation) raw data from the tensile strength test conducted at room temperature using Type IV and/or Type V specimens (as described in ASTM D638) at a test speed of 7 mm/min. Three different approaches are used to define the strain hardening modulus and to compare the representative strain hardening modulus with the SP-NCTL SCR. It is shown that the high test speed of 7 mm/min performed at room temperature provides a good correlation with the SP-NCTL SCR of different smooth black HDPE geomembranes. Additionally, the proposed method using Type V specimens predicts the SCR values during oxidative degradation close to those observed using the SP-NCTL SCR test. For the resins and conditions examined, the proposed method provides a quick assessment of the SP-NCTL SCR of unaged geomembranes when the SP-NCTL SCR takes long testing times (e.g., >1000 h) or in jurisdictions in which the use of surfactants becomes prohibited to allow conducting the SP-NCTL SCR tests. • Presents a correlation between the NCTL-SCR of HDPE GMBs and strain hardening slope at room temperature at 7 mm/min. • Presents a correlation with a transformed post-yield load-elongation curve for unaged specimens using Type V and IV specimens. • Presents a correlation with a transformed post-yield load-elongation curve for aged and unaged specimens using Type V specimens. • Shows that the strain hardening test conducted at room temperature at 7 mm/min can predict the SCR with the same level of accuracy as the NCTL tests. [ABSTRACT FROM AUTHOR]

Geomembranes (GMBs) and geotextiles (GTXs) are the most widely used geosynthetics in landfills and other barrier systems. While various temperature environments may be encountered in practice, the interface shear characteristics of geosynthetics under different temperatures are still not clear. Shear tests of the interface between a high-density polyethylene GMB and nonwoven GTX are performed using a temperature-controlled submerged direct shear apparatus. The testing temperatures range from 10 °C to 70 °C, which covers most of the situations commonly encountered in engineering. The shear behaviors of the textured GMB/GTX interface and smooth GMB/GTX interface are presented, and the mechanism of the temperature influence is analyzed according to the test results and phenomena. Temperature has a significant impact on the GMB/GTX interface peak strength and post-peak strength, and maximum interface shear strength could be obtained when the temperature is approximately 30–40 °C. The influencing mechanisms of temperature on the GMB/GTX interface shear strength are thoroughly discussed. The shear characteristics of the GMB/GTX interface under different temperatures are critical to the stability analysis of geosynthetic slopes in special condition, and this study can also provide a reference for the effect of temperature on the shear behavior of other geosynthetics. • Submerged shear tests of the GMB/GTX interface are conducted at wide temperature ranges covering most of the situations. • Significant weakening of the GMB/GTX interface shear strength has been confirmed to exist at high temperatures. • The influencing mechanism of temperature on interface friction is different from that on asperity interlocking. [ABSTRACT FROM AUTHOR]

The stress crack resistance (SCR) of high-density polyethylene (HDPE) geomembrane extrusion welds is examined for a 1.5 mm HDPE geomembrane and three different welding parameter combinations (denoted as "Cool", "Good", and "Overheated"). Results are reported for unnotched welds, unnotched sheet, and notched sheet. The average SCR for a Good extrusion weld is 23% of that of the unnotched sheet SCR. Little variation is found between the three welding parameter combinations for low geometry irregularity SCR weld specimens. There is no statistically significant difference between a good-quality fusion and extrusion weld. However, operator-dependent weld induced geometric irregularity (WIGI) greatly affects the SCR of extrusion welds. Extrusion welds with high WIGI have an average unnotched SCR of only 9% of the unnotched sheet. Extrusion welds with an overground surface can have an unnotched SCR as little as 1% of the best extrusion weld. Deleterious weld bead geometries are identified to provide a framework with which engineers can identify "high-risk" extrusion welds with respect to stress cracking. • Paper highlights: • First examination of the effects of weld-induced geometric irregularity (WIGI) in extrusion welds on unnotched stress crack resistance. • Highlights the impact of poor quality control for extrusion welds (e.g., overgrinding, high WIGI, and scratches) on the likelihood of stress cracking in the field. • Demonstrates that a good extrusion weld (i.e., low WIGI, good grinding, and appropriate welding temperature) has a comparable unnotched stress crack resistance to that of a good fusion weld. • Demonstrates that the operator-dependent nature of extrusion welds substantially increases the variability in the stress crack resistance of extrusion welds compared to fusion welds. • Highlights the importance of doubling the standard oxidative induction time (Std-OIT) of welding rod to reach a post-welded bead's Std-OIT similar to the sheet's Std-OIT (i.e., it shows a 50% decrease in Std-OIT of the extruded bead compared to the initial rod entering the extruder). [ABSTRACT FROM AUTHOR]

The development of easy and direct real-time monitoring of welded joint quality instead of surface damage analysis is crucial to improve the quality of industrial products. This work presents the results of high-density polyethylene (HDPE)-based composites with various carbon black (CB) content (from 20 to 30 vol.%) for use as a heating element and strain sensor in electrofusion-welded polymer joints. The pyroresistive heating process was used to determine the effect of generated Joule heat during welding on the structure and sensor properties of polymer–carbon composites. It is shown that the generation of Joule heat depends on the nanocarbon content and affects the crystallinity of the polymer matrix. The partial disruption of the conductive path of carbon black particles was observed and, as a result, a decrease in electrical conductivity for composites with lower CB content after welding was found. For the highest CB amount, conductivity increased, which is caused by smaller particle-to-particle distance for filler paths. Therefore, the best balance between pyroresistive and sensor properties was found. [ABSTRACT FROM AUTHOR]

Terahertz (THz) fields are increasingly being used to address the critical challenges associated with achieving high data rates and rapid communication. In this study, a hybrid plasmonic THz waveguide is designed and analysed operating in the 2.5–3.5 THz frequency range. The waveguide is constructed using gallium arsenide as the high-refractive-index core, surrounded by aluminium arsenide and silver placed on a high-density polyethylene (HDPE) substrate. Graphene is strategically positioned between the HDPE layers to enhance light confinement. The mode properties of the proposed waveguide are simulated with Comol Multiphysics using the finite-element method and show unique characteristics. Observation of the simulated results at 2.5–3.5 THz reveals a high effective refractive index of 3.79, a maximum effective mode area of 1.88 mm2, a high birefringence of 0.2, a low dispersion of 0.10 ps THz−1 cm−1, a high mode field diameter of 15.8 mm, a high beat length of 123 mm and a low confinement loss of 1.79 × 10−9 mm−1. These features make the proposed waveguide suitable for applications in photonic integrated circuits for THz communications. [ABSTRACT FROM AUTHOR]

Most of the artworks stored in museums are often kept in inappropriate climatic and environmental conditions that facilitate the formation and growth of microorganisms, such as fungi, which are responsible for many types of biodegradation phenomena. To mitigate and prevent these deteriorative processes, functionalized packaging materials can be used for the storage and handling of artworks. The aim of this study was to develop a potential anti-biodeterioration coating suitable for packaging purposes. TiO2 and ZnO doped with different amounts of Ag (0.5 wt%, 1 wt%, and 3 wt%) were synthesized and dispersed in polyvinyl alcohol (PVA) and acrylic resin (Paraloid B72), then applied on different types of packaging materials (cellulose and the high-density spunbound polyethylene fiber Tyvek®, materials that are frequently used as packaging in museums). Analytical investigations (SEM/EDS, Raman, FTIR, and XRD) were employed to assess dispersion on the packaging material. Furthermore, resistance against biodeteriogens was assessed using Cladosporium sp., a bioluminometer, to define the biocidal efficacy. [ABSTRACT FROM AUTHOR]