Search

There are many photovoltaic (PV) applications where lighter weight and/or bendable PV power would be beneficial. This includes the curved surfaces of buildings, buildings with weight limitations, boats, automobiles, or other portable applications. In many of these cases, the bending will be only a single occurrence at installation or the amount of bending, even if repeated, is not dramatic. This allows for crystalline silicon modules to be used. For flexible applications, the dominant material for the frontsheet is polyethylene tetrafluoroethylene (PETFE). As a fluoropolymer it resists soiling, is UV stable, and PETFE is a more mechanically durable fluoropolymer. However, in the interests of keeping costs down, less expensive alternative polymers are desirable. In this study, highly accelerated ultraviolet light and heat stresses are applied to candidate materials and the degradation kinetics are determined to provide information to evaluate their suitability for use in a PV application.

This research explores a segment of the mechanical, thermal & physical characteristics of a polymer polypropylene (PP) mixture including low density polyethylene (LDPE). There were mixing syntheses (pure PP, 25 LDPE/75PP, 50LDPE/50PP, 75LDPE/25LDPE, pure PP) that were examined. As outcome, the expansion of LDPE to PP has decreased, with improved thickness, elasticity, bending efficiency, versatile modulus and hardness. In a (25LDPE/75PP) arrangement the prevailing elasticity was achieved while the (50LDPE/50PP) synthesis was attributed to ideal bent efficiency. High density polyethylene (HDPE) blowing in different proportions PP/polyethylene (PEs) can remove sorting course employed during even recycling course. PP has interesting features like outstanding process ability &tolerance to chemicals. Inadequate versatility, however, limits its usage in specific applications. Mixing PP with relative PEs may enhance its versatility. Universal kinetics of PP crystallization have been affected greatly by the existence of PEs of various structures of the ramifications. Existence of LDPE reduced overall summation ratio while HDPE increased the process of crystallization. No negative effect was observed in the studied parameter range on mechanical performance and the related crystallinity.

The research on jute fiber reinforced polymer composites is an emergent concern with the development of new materials due to their significant properties like economical, partially biodegradable, and environment friendly. It is wondered that the hydrophilic nature of jute fiber negatively affects the interfacial interaction with hydrophobic polymeric materials in the composite, which then affects the resultant mechanical, microstructural and physico-chemical absorption properties. In order to overcome this fact, researchers have carried out some techniques for fiber surface chemical treatments. On the other hand, due to the low processing costs and design flexibility, thermoplastics deal many benefits over thermoset polymers, and polyethylene shows excellent processing behaviors such as low density, low cost, considerable flex life, outstanding surface hardness, scratch resistance and good electrical insulator. Besides the traditional thermoplastic and thermosetting polymers, montmorillonite nanoclay is also receiving attention to manufacturing fiber polymer nanocomposites for industrial and household applications as well. This review is considered to highlight the progress of jute fiber reinforced polymer nanocomposites. The study also focuses on the several features of jute polymer composites and nanocomposites as a function of fiber chemical treatments.

Polypropylene (PP) and polyethylene (PE) play central roles in our daily life. However, their immiscibility presents a major hurdle in both industry and academia when recycling them into alloys with favorable mechanical properties. Moreover, typical compatibilizer-enabled approaches are limited due to increased environmental concerns. Herein, inspired by a traditional Chinese technique, we report a facile, industry-scale methodology that produces a PP/PE binary blend with a highly ordered honeycomb nanostructure without any additives. Due to its nanostructure, the blend exhibits enhanced tensile properties in comparison with the parent components or with a sample prepared using an internal mixer. This approach has potential for applications not only in immiscible polymer blending, but also in non-sorting, compatibilizer-free waste plastics recycling. Through this technique, we expect that an environmentally friendly and sustainable plastic wastes recycling avenue can be found, and great economic benefits can be gained.

In households, considerable costs are related to energy losses, which are a consequence of maintaining comfortable living temperatures. Improved isolation and utilization of energy harvesting devices is the key to reducing energy losses and the related costs. Polymeric solar absorbers are cost-effective solar energy harvesters that can significantly reduce the energy cost for individual households. One of the concerns related to polymers is their flammability. To mitigate the flammability risk, the present work explores the development of solar absorber paints with flame-retardant properties. Bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivatives (NED and PHED) in concertation ranges of 10–15 wt% were used in a polyurethane-based matrix to demonstrate the effect of additives on the fire retardancy of the material. Additionally, the rheological and thermal properties of the composite materials were evaluated and described. Furthermore, aluminium and PPS (polyethylene sulphide) substrates were coated with solar absorber paint based on a 15% FR (fire retardant) additive formulation, for which the thermal stability at 150 °C for 655 h was evaluated. It was discovered that PHED is more compatible with the polyurethane matrix than NED, and as expected, a greater amount of FR additives resulted in improved flame retardancy. The long-term stability of absorber paint coatings on Al and PPS was also successfully confirmed by confirming stable solar absorptance and thermal emittance. In future prospects, we believe that the flame retardancy of polyurethane-based coatings could be further improved, and the utilization of covalently bonded FRs should also be considered.

A highly sought-after objective of Space Agencies is the development of additive manufacturing (AM) technologies and of multifunctional materials, key elements to future exploration and colonization of Moon and Mars. The 3D printing process via fused filament fabrication (FFF) is increasingly viewed as an interesting approach for the in-situ manufacturing of buildings and items using regolith as a feedstock material, enabling the necessary repair and recycling capabilities to ensure crew safety. In this work, we investigate the radiation shielding properties and the FFF 3D printing process of polyethylene-based composites filled with Martian regolith. The on-line tool for the assessment of radiation in space (OLTARIS) software developed by NASA was used to assess the radiation shielding effectiveness of polyethylene (PE)/regolith (RG) composites in the Martian radiation environment. A basalt powder with chemical composition similar to that of Mars soil was used as Martian regolith simulant in the 3D printing process. Differential scanning calorimetry (DSC) was used to determine the melting properties and crystallization degree of PE/RG composites at different RG concentrations, in order to analyze the effect of the simulant on the process parameters of filament extrusion and 3D printing. Low-impact Izod tests were also performed, with all PE/RG composites showing improved impact strength with respect to neat PE. Based on the DSC and Izod tests results, filaments of PE/RG composites were fabricated and used to 3D-print samples for tensile tests and 3-point bending tests. Results demonstrate the radiation shielding effectiveness of PE/RG composites and the capability of 3D-printers based on FFF to successfully manufacture components made of PE/RG composites starting from extruded filaments.

When utilised in arthroplasty applications, ultra-high-molecular-weight polyethylene (UHMWPE), the gold standard material for artificial joints, creates wear debris. The life of UHMWPE joints is generally restricted to 15–20 years due to unfavourable interactions of wear debris with surrounding tissues. Various attempts have been made in recent decades to enhance the material's wear resistance and performance. This study looks at the changes that have been made to increase its mechanical characteristics and wear resistance. Functionalization techniques, enhanced surface or bulk properties, and their various applications in medical implant fields (total hip arthroplasty, bone tissue engineering, joint implants) have all been extensively studied. A descriptive study of pure UHMWPE and its composite has been conducted in order to functionalize the features of medical implants.

In the present study, we investigated the possibility of value-added recycling of ultrafine ground tire rubber (uGTR) produced from water jet milling, with an average particle size of a few tens of microns. Our goal was to compare the properties of blends with different uGTR and conventional fine ground tire rubber (fGTR) contents prepared by blending with low-density polyethylene (LDPE). We also aimed to explore the property changes caused by the larger specific surface area due to the size effect. Samples were prepared with a hydraulic press after internal mixing. In the case of ground tire rubber (GTR) filled mixtures, the tensile properties showed rubber-like characteristics: with a significant decrease in modulus, elongation at break remained high, and tensile strength slightly decreased. The fracture surfaces of the samples were analyzed by scanning electron microscopy (SEM), wherein the case of materials made with uGTR showed better adhesion between the phases. In order to investigate the interfacial adhesion between the GTR and LDPE, we performed dynamic mechanical thermal analysis (DMTA). The glass transition peak of the uGTR shifted to a higher temperature and the storage modulus was higher than in the case of samples containing fGTR. Finally, we determined the Shore D hardness of the materials, which decreased with increasing GTR content, but hardness was greater in the case of uGTR samples. The better mechanical properties of blends containing uGTR were explained by better interfacial adhesion between the two phases due to the significantly higher specific surface area compared to fGTR.

Natural fibres now a days replacing the conventional structural materials such as Aluminium, steel, wood etc. with their excellent weight to strength ratio and with their high mechanical properties. In this present investigation hybrid composites were fabricated using Hand layup process using the natural fibres such as Banana, Coconut, Jute and Cotton fibres reinforced with Polyethylene at different weight proportions of 5, 8, 10, 12, 15, 18, 20 wt%. Tests such as water absorption, flexural rigidity, tensile, hardness and few other mechanical tests were conducted on the hybrid natural fibre reinforced composites. Among the hybrid composites the coconut fibre with 20 wt% and banana fibre with 18% shows high tensile strength with 56.4 N/mm2 and 54 N/mm2 and flexural strength. Water absorption is less in the hybrid composite with coconut and cotton fibres as reinforcements and gains mass of 5gm and 7gm.

In the recent decade, there has been an increase in global warming, environmental changes, and other issues. Environmentally friendly products, such as natural composite materials, are being developed by researchers and academics to protect life on the planet. The purpose of this research is to see if cellulose and cellulignin fibres obtained from sugarcane bagasse (SCB) waste may be used as reinforcing filler in a thermoplastic polymer matrix. The injection method was used to create the low density polyethylene (LDPE) and sugarcane bagasse (SCB) composites. Fiber loading was set to be varied from 10 to 30 wt%. To improve interfacial bonding, the fibres were chemically modified using an alkali treatment, and the effects on the fiber/matrix interaction were evaluated using scanning electron micrographs (SEM). Tensile, impact, and hardness were used to determine the mechanical properties and corrosion tests. The findings revealed that sugarcane bagasse fibers, like other natural fibers, strengthen polyethylene. It has been found that the tensile strength and tensile modulus of the treated SCB fibers have been improved significantly by about 13% and 196%, respectively, compared to neat LDPE. This was due to the observed enhancement in the interfacial adhesion between the fiber and matrix. The impact resistance and hardness of the composite enhanced by 55.28% and 26%, respectively, over neat LDPE. According to SEM analysis, the alkali treatment affected the morphology of fibers.

Aims The aim of this study was to investigate whether wear and backside deformation of polyethylene (PE) tibial inserts may influence the cement cover of tibial trays of explanted total knee arthroplasties (TKAs). Methods At our retrieval centre, we measured changes in the wear and deformation of PE inserts using coordinate measuring machines and light microscopy. The amount of cement cover on the backside of tibial trays was quantified as a percentage of the total surface. The study involved data from the explanted fixed-bearing components of four widely used contemporary designs of TKA (Attune, NexGen, Press Fit Condylar (PFC), and Triathlon), revised for any indication, and we compared them with components that used previous generations of PE. Regression modelling was used to identify variables related to the amount of cement cover on the retrieved trays. Results A total of 114 explanted fixed-bearing TKAs were examined. This included 76 used with contemporary PE inserts which were compared with 15 used with older generation PEs. The Attune and NexGen (central locking) trays were found to have significantly less cement cover than Triathlon and PFC trays (peripheral locking group) (p = 0.001). The median planicity values of the PE inserts used with central locking trays were significantly greater than of those with peripheral locking inserts (205 vs 85 microns; p < 0.001). Attune and NexGen inserts had a characteristic pattern of backside deformation, with the outer edges of the PE deviating inferiorly, leaving the PE margins as the primary areas of articulation. Conclusion Explanted TKAs with central locking mechanisms were significantly more likely to debond from the cement mantle. The PE inserts of these designs showed characteristic patterns of deformation, which appeared to relate to the manufacturing process and may be exacerbated in vivo. This pattern of deformation was associated with PE wear occurring at the outer edges of the articulation, potentially increasing the frictional torque generated at this interface. Cite this article: Bone Joint J 2021;103-B(12):1791–1801.

The osteochondral lesions and osteoarthritis-related complications continue to be clinically relevant challenges to be addressed by the biomaterials community. Hydrogel-based scaffolds have been widely investigated to enhance osteochondral regeneration, but the inferior mechanical properties together with poor functional stability are the major constraints in their clinical translation. The development of osteochondral implants with natural tissue-mimicking mechanical properties remains largely unexplored. In this perspective, the present study demonstrates a strategy to develop a bilayer osteochondral implant with an elastically stiff composite (poly(vinylidene difluoride)-reinforced BaTiO

Geocells are three-dimensional expandable panels composed of polymers such as polyolefin polymers. Currently, geocells are being extensively used in various geotechnical engineering applications; however, its applications are limited because of the sizeable long-term deformation under constant loading and poor tensile strength. Owing to the rapid growth rate of geocells, it has become necessary to develop a polymer material with excellent creep resistance and tensile strength. To this end, a polymer-blend geocell (PBG) is developed in this study using a twin-screw extruder with high-density polyethylene (HDPE), polyamide 6, and compatibilizer. The polymer formula is determined by the tear fracture surface and scanning electron microscopy. The tensile properties of the blends with different formulas are studied in terms of yield strength, tensile strength, and elongation at break. Finally, three types of PBG and HDPE geocells are selected to study the long-term creep behavior using accelerated creep tests. The analysis results of raw creep data, master creep curve, and isochronous creep curves indicated that the PBG had a better creep resistance than the HDPE geocells.

Though fibres are being used in concrete structures for a couple of decades, the use of polymeric Synthetic Fibres (SyF) such as Polypropylene Fibre (PPF), Polyethylene Fibre (PEF) and Polyvinyl-alcohol Fibre (PVAF) found more rapid growth in recent years. The higher durability and physical properties of SyF increased its use in concrete despite there are some drawbacks in mechanical performances. However, the development of high modulus SyF and the use of hybrid Fibre Reinforced Concrete (FRC) systems helped to mitigate the mechanical performance drawbacks to produce superior Synthetic Fibre Reinforced Concrete (SyFRC) to use in structural elements. This paper presents the recent developments and applications of SyFRC in structural elements along with the material properties such as mechanical, fire and durability performances of SyFRC.

This study aims to improve the tensile properties of the polyethylene film deposited with a multilayer graphene membrane, in order to establish the understanding of the influence of the methane to hydrogen ratio on the tensile properties of the multilayer graphene membrane. Multilayer graphene membranes were prepared using the chemical vapor deposition method. Four types of multilayer graphene membranes were prepared with different ratios of methane to hydrogen before depositing a membrane on the polyethylene film. Experiments showed that the tensile strength of the polyethylene films with multilayer graphene deposition increased 7 times and the Young’s modulus 5 times more than that of pure polyethylene films, when the ratio of methane to hydrogen was set to 35/100 sccm. A compromise between hydrogen and methane mixture is required to achieve uniform growth of graphene. Insufficient hydrogen cannot activate the surface bound carbon that is necessary for continuous growth. Continuous and well-defined multilayer graphene was synthesized when the ratio of methane to hydrogen reached up a proper value.

We examined the general rheological characteristics of short-chain branched (SCB) ring polyethylene (PE) melts using atomistic nonequilibrium molecular dynamics (NEMD) simulations under shear in a ...

Bulletproof fabrics are usually used as create jackets to protect the user from being shot. These jackets are varied write as according to the degree of expected risks and required levels of protection. Different types of materials and fibers could be used for achieving many properties and different levels of protections. The type and number of materials were affected on the required protection. The current market is looking to reduce the weight and thickness of these fabrics, in addition to low cost. In all bulletproof protective clothing, there is a certain basic material that contributes to stopping the bullet in a noticeable way. Currently, materials made of high molecular weight polyethylene (UHMWPE) and aramid fibers are widely used for this purpose. Aramid fibers are developed by upgrading ballistic nylon fibers while UHMWPE is developed from polyester. Kevlar 29 and Kevlar 149 are the dominant body armor material belonging to the aramid fibers. Dyneema is another UHMWPE. The molecular formula of this polymer is the same as common polyethylene but differs greatly due to its very high molecular weight, 10 to 100 times higher than that of commercial polyethylene resin. This research paper goals to investigation into Kevlar and Dyneema fabrics to obtain the best functional properties of bulletproof fabrics. The samples were produced with a plain 1/1 structure. After the fabric samples were produced, tests were carried out to evaluate the samples produced such as, Tensile Strength, UV resistance, Heat Conductivity, Abrasion Resistance, washability, Chemical Resistance, Thermal Properties, the results revealed the superiority of Dyneema fabrics in terms of functional properties over Kevlar fabrics, as it has many properties that qualify it to be a bulletproof fabric.

In this study, titanium dioxide (TiO2) and polyethylene (PE) fibers were employed to develop photocatalytic high-performance fiber-reinforced cement composites (HPFRCCs). To achieve high NOx removal capacity, it was necessary to confirm the dispersion of the TiO2 powder. For this purpose, various amounts of viscosity-modifying agent (VMA), ranging from 0% to 1% by weight to cement, were considered along with two types of white Portland cement: Union and Aalborg. Additionally, the PE fiber surface was modified via cold gas plasma and chromic acid treatment to improve the tensile performance of the HPFRCCs. The experimental results indicated that the plastic viscosity of the mortar increases with the addition of VMA. Optimum NOx removal capacities of 5.72 and 8.10 μmol were respectively achieved for the Aalborg and Union cement types in the mortar at a VMA content of 0.5%. The compressive strength of the tested photocatalytic HPFRCC was approximately 72.7–91.8 MPa. In the case of the hybrid argon (Ar) and oxygen (O2) gases being subjected to plasma treatment, optimum tensile performance—in terms of tensile strength, strain capacity, and g-value—was achieved, whereas the samples subjected to chromic acid treatment exhibited poorer tensile performance. Moreover, the single Ar–or O2-gas-based plasma treatment yielded an intermediate tensile performance. The cracking behavior showed trends similar to those of the g-value: the hybrid plasma treatment produced the most microcracks because of its high fiber bridging capacity.

Energetic ion beam experiments with major space radiation elements, 1H, 4He, 16O, 28Si and 56Fe, have been conducted to investigate the radiation shielding properties of composite materials. These materials are expected to be used for parts and fixtures of space vehicles due to both their mechanical strength and their space radiation shielding capabilities. Low Z materials containing hydrogen are effective for shielding protons and heavy ions due to their high stopping power and large fragmentation cross section per unit mass. The stopping power of the composite materials used in this work is intermediate between that of aluminum and polyethylene, which are typical structural and shielding materials used in space. The total charge-changing cross sections per unit mass, σ UM , of the composite materials are 1.3–1.8 times larger than that of aluminum. By replacing conventional aluminum used for spacecraft with commercially available composite (carbon fiber / polyether ether ketone), it is expected that the shielding effect is increased by ∼17%. The utilization of composite materials will help mitigate the space radiation hazard on future deep space missions.

The anti-penetration performance of the composite armor structures, which are composed of steel, Kevlar composite, and ultra-high molecular weight polyethylene (UHMWPE) composite, were investigated...

In this paper, multiwall carbon nanotube-ZnO (MWCNT/ZnO) was melt-blended with polyethylene (PE) by a Haake-Buchler Rheomixer. The mechanical properties, thermal stability and dispersion degree of the composite materials was characterized. Differential scanning calorimetry, X-ray diffraction analysis, thermogravimetry, tensile test and SEM were carried out. The results showed that with the addition of MWCNT/ZnO, the crystallinity and thermal degradation temperature of PE changed. 0.2phr MWCNT/ZnO/PE exhibited crystallinity that was 10% higher than PE. With the addition of MWCNT/ZnO, the tensile strength of PE decreased gradually, but the elongation at break increased first and then decreased. When MWCNT/ZnO content is 0.2phr, the elongation at break of the composite is close to 532.21%, which is 116% higher than that of pure PE.

High-density polyethylene (HDPE) pipes have become the preferred water pipes in nuclear power plants. Since the butt fusion–welded joint of HDPE pipes is a weak link of a piping system, it is essential to study the creep properties of the welded joint. In this study, the creep properties of the welded joint of HDPE pipes were studied using a nanoindentation creep test. The test results showed that the weakest creep resistance was not located in the weld center, but was a little away from the weld center. The power-law creep constitutive model was constructed at different locations of the welded joint based on the test results. In addition, the hardness of the welded joint was tested. The results showed that the hardness of the welded joint could reflect the creep resistance of the welded joint.

In this work, a natural fiber obtained from a water hyacinth (WH) plant was used as reinforcement in high-density polyethylene (HDPE) for the fabrication of WH/HDPE composite by the compression molding process. Fabrication parameters such as water hyacinth content, alkali treatment concentration, treatment time, and coupling agent amount were varied in three levels, and composites specimens were fabricated according to Taguchi’s L9 orthogonal array. Grey Relation Analysis was used to optimize the fabrication parameters. The results showed that the increase in WH fiber volume fraction, NaOH concentrations, and treatment time increased the tensile and flexural strength of the composite up to some point and after that, it decreased. However, the strength of the composite was found to decrease with the increase in NaOH concentration and decrease in coupling agent concentration. It was revealed that the water hyacinth particle content had the highest contribution to tensile and flexural strength, followed by coupling agent dosage, treatment time, and NaOH concentration in order. Mechanical properties were optimized when the WH/HDPE composite was fabricated with 30% water hyacinth fiber, treated with 5wt% NaOH concentration for 12 h, and mixed with a 15% coupling agent. The fabricated WH/HDP composite can be used as a viable alternative material for making furniture, ceiling, tile, and partition boards.

Polyethylene (PE) cable has become an important carrier of the modern power grid due to its excellent electrical insulation performance. However, small damages can inevitably occur during the preparation and operation of the materials, which can distort electric field and trigger discharge, seriously threatening power supply safety. The self-healing of insulation materials by doping microcapsules is a new research innovation. In this paper, the self-healing PE/microcapsules insulation composite material was prepared, and the self-healing behavior of mechanical damage was emphatically analyzed by scratch damage test and crack propagation simulation. The results show that the composite material with 1 wt% microcapsule has better insulation strength. Moreover, the composite material can fill the defective structures, restore local electrical properties, and reverse the deterioration process of the material. The properties of PE/microcapsules composite material are mainly related to the characteristics of the microcapsule itself and the interface introduced by the microcapsules. The properties of the repaired product can directly affect the recovery degree of the damaged area. The stress action during damage can smoothly trigger its self-healing behavior. In conclusion, the PE composite material doped with 1 wt% microcapsules can achieve a good self-healing effect on mechanical damage.

In this study, the effects of filler amounts were studied on the mechanical and thermal properties of high-density polyethylene (HDPE), polystyrene (PS) and polyoxymethylene (POM) polymers reinforced with short rape fibers. HDPE-rape, POM-rape and PS-rape fiber composite materials were prepared with different fiber contents and their tensile, flexural, Izod impact and TGA/DTA properties were examined. When tensile and Izod impact properties were compared, it was observed that an increase in the amount of filling in HDPE-based composites did not cause any significant changes in these peoperties, while they were decreased for POM- and PS-based composites. On the contrary to tensile and impact strengths, when the three-point flexural properties were examined, it was observed that the strength values of all these materials increased with increasing the amount of fillers. However, a pronounced increase was observed in the three-point flexural strength of the HDPE-based composite materials. The flexural strength of 30 wt% rape-reinforced HDPE composite was found to be twice that of the pure HDPE. The results of TGA and DTA analyses revealed that the reinforcement element started to burn before the matrix material and therefore burning was delayed in these thermoplastics. As a result, the mechanical properties of HDPE composite materials improved with rape reinforcement. In this way, by using approximately 30 wt% natural filling material in a polymeric matrix, an environmentally friendly material, as well as, significant advantages in cost can be obtained.

The process of obtaining aerated (filled with air bubbles) polymer coatings has been developed and investigated by the method of flame spraying with an assessment of their ability to damp vibrations. A technology for the controlled formation of aerated polymer coatings has been developed while using the capabilities of the ОИМ (OIM) 050 polymer thermal atomizer design which consists in providing a concurrent air flow between the flame torch and the jet of powder material. The experiments have been carried out with such thermoplastic polymers as polyethylene terephthalate, high pressure polyethylene, ultra high molecular weight polyethylene, polyamide. It has been found that the aeration coefficient grows almost in direct proportion with an increase in the amount of air in the concurrent flow for all investigated polymer coatings. It is noted that the aeration process is influenced by the rheological properties of liquid polymers, or rather, the value of the polymer melt flow rate. The limiting values of air in the concurrent flow have been determined, which make it possible not to reduce the adhesion of polymer coatings to steel substrates by less than 6 MPa and not to decrease their hardness by more than 25–30 %. Studies of the damping properties of samples with polymer coatings have been carried out on a stand, the kinematic diagram of which is based on loading the free end of a cantilever sample, abrupt removal of the load and registration of free damped oscillations by an induction-type contactless sensor connected to a computer. It is shown that the use of aeration when forming noise-absorbing coatings on steel samples can increase their logarithmic damping decrement by 18–26 %.

Plastic deformation of polyethylene in uniaxial and biaxial loading conditions is studied using molecular dynamics simulation. Effects of tensile strain rates from 1 × 105 to 1 × 109 s−1, and mass density in the range of 0.923–0.926 g/cm3 on mechanical behaviour and microstructure evolution are examined. Two biaxial tensile deformation modes are considered. One is through simultaneous stretching in both the x and y directions and the other sequential stretching, firstly in the x-direction and then in the y-direction while strain in the x-direction remains constant. Tangent modulus and yield stress that are determined using the stress–strain curves from the molecular dynamics simulation show a strong dependence on the deformation mode, strain rate and mass density, and all are in good agreement with results from the experimental testing, including fracture behaviour which is ductile at a low strain rate but brittle at a high strain rate. Furthermore, the study suggests that the stress–strain curves under uniaxial tension and simultaneous biaxial tension at a relatively low strain rate contain four distinguishable regions, for elastic, yield, strain softening and strain hardening, respectively, whereas under sequential biaxial tension, stress increases monotonically with the increase of strain, without noticeable yielding, strain softening or strain hardening behaviour. The molecular dynamics simulation also suggests that an increase in the strain rate enhances the possibility of cavitation. Under simultaneous biaxial tension, with the strain rate increasing from 1 × 106 to 1 × 109 s−1, the molecular dynamics simulation shows that polyethylene failure changes from a local to a global phenomenon, accompanied by a decrease of the void size and increase of uniformity in the void distribution. Under sequential biaxial tension, on the other hand, the density of the cavities is clearly reduced.

Samples of LDPE (low-density polyethylene) and LDPE-PANSA (low-density polyethylene -4-Amino-3-hydroxy- 1-naphthalenesulfonic acid) copolymer with Ag0.5�Ni0.5�Fe2O4 powder (as a filler) composites were developed. Following the preliminary characterizations on the thermooxidability (by thermal analysis techniques), the dielectric behavior (by dielectric spectroscopy technique), the mechanical behavior, etc. it was found that the developed materials do not show significant changes after 240 h exposure to 150 mW / m2 UV. The addition of 3wt% PANSA in LDPE has the effect of increasing the mechanical performance of polymer composites with Ag0.5�Ni0.5�Fe2O4 filler. The addition of 15 wt% ferritic powder leads to significant increases in dielectric losses (by about 100% in the case of pure LDPE and about 185% of the LDPE copolymer with 3 wt% PANSA) and to the increase of the real component of the relative permittivity (by about 34.4 % in LPDE, respectively about 36.4% in LPDE copolymer / 3% wt PANSA). Dielectric behavior of the investigated materials indicates that the effect of Ag0.5�Ni0.5�Fe2O4 powder in LDPE and of copolimer LDPE with 3 wt% PANSA consists in the increasing of the shielding efficiency of electromagnetic waves - the maximum effect being recorded in the case of the composite material with the content: LDPE 84.5 wt%, 2.5 wt% / PANSA and 13% wt% Ag0.5�Ni0.5�Fe2O4.

The molecular weight of ultra-high molecular weight polyethylene (UHMWPE) fibers is severely decreased compared with raw materials due to high temperature and strong shearing in the dissolving process. In this study, we reported a novel method to assist the dissolving of UHMWPE in paraffin oil without severe degradation in order to improve the tensile strength of resultant fibers. UHMWPE fibers with relatively high molecular weight and more excellent disentanglement effect were prepared by gel-spinning with UHMWPE suspension treated with supercritical carbon dioxide (SC-CO2). The dynamic thermomechanical, mechanical and crystalline properties of UHMWPE extracted fibers and drawn fibers were researched comprehensively. UHMWPE extracted fibers obtained after SC-CO2 treatment display a higher molecular weight. More importantly, it is clear that the disentanglement of UHMWPE gel fibers gained by processing SC-CO2 has been significantly promoted compared with that without SC-CO2 treatment from dynamic thermomechanical and rheological results, which could also be demonstrated from the cross-sectional morphology of UHMWPE extracted fibers. Furthermore, the tensile strength of UHMWPE fibers prepared through SC-CO2 treating is able to attain 30.11 cN/dtex, increased by 10.3% in comparison to UHMWPE fibers gained without assistance of SC-CO2. Beyond that, the thermal behavior and crystallization performance of UHMWPE extracted fibers and drawn fibers acquired by way of SC-CO2 treatment have also been enhanced.

Montmorillonite (MMT) clays are important industrial materials used as catalysts, chemical sorbents and fillers in polymer–clay nanocomposites. The layered structure of these clays has motivated research into further applications of these low-cost materials, including use as ion exchange media and solid-state ionic conductors. In these applications, the mechanical properties of MMT are key when considering long-term, reliable performance. Previous studies have focused on the mechanical properties of nanocomposites with MMT as the minority component or pure MMT thin films. In this work, the microstructure and mechanical properties of pure MMT and majority MMT/polyethylene composites pressed into dense pellets are examined. Characterization methods such as X-ray diffraction, atomic force microscopy and scanning electron microscopy together with nanoindentation reveal important structure–property relationships in the clay-based materials. Utilizing these techniques, we have discovered that MMT processing impacts the layered microstructure, chemical stability and, critically, the elastic modulus and hardness of bulk MMT samples. Particularly, the density of the pellets and the ordering of the clay platelets within them strongly influence the elastic modulus and hardness of the pellets. By increasing pressing force or by incorporating secondary components, the density, and therefore mechanical properties, can be increased. If the layered structure of the clay is destroyed by exfoliation, the mechanical properties will be compromised. Understanding these relationships will help guide new studies to engineer mechanically stable MMT-based materials for industrial applications.

The separators have an impact on the performance of lithium-based battery, whereas traditional polyolefin separators are hard to retain enough liquid electrolyte for its nonpolar surface and lead to battery performance degradation. In this experimental work, we have tried to activate polyethylene (PE) separator by γ-ray irradiation with different doses. According to these results of FTIR-ATR, the contact angle and mechanical test, it is concluded that γ-ray irradiation would get the PE long chains broken and oxidized furtherly. Therefore, these irradiated separators show a higher surface energy and inferior mechanical strength than pristine PE separator. For comprehensive consideration, the PE-20 (irradiated by the dose of 20 kGy) separator is selected to evaluate the electrochemical performance. The LiCoO2 cells with PE-20 separators have a better cyclic stability than that of PE separator for lower interfacial resistance and stronger affinity to liquid electrolyte. Especially in the unsymmetrical rate performance test, the cells based on PE-20 separator have higher discharge capacity. It demonstrates that this method of γ-ray irradiation could be used to modify PE separator for enhancing battery performance.

In this study, the composite materials based on high density polyethylene (HDPE) and yellow phosphorus slag (YPS, by-product of yellow phosphorus production) were prepared using melt blending metho...

This paper presents an experimental study of the effects of thermal aging on the insulation characteristics of cross-linked polyethylene (XLPE) medium voltage cables. These cables are installed in Algeria where they are designed to withstand high temperatures and humidity levels. Therefore, the main objective of this work is to report experimental results concerning the effects of accelerated thermal aging and water adsorption on the XLPE insulation properties. For this purpose, mechanical characterization and visual observation analysis are performed. In addition, complementary diagnostic measurements, including Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC), are carried out. Furthermore, a correlation between XLPE mechanical, physical, and physico-chemical changes due to thermal and water adsorption is deduced.

Several fluorinated polyethylene surface studies have proved that the fluorination reaction can effectively prevent charge from being injected into polyethylene. Therefore, this paper explores the influence of fluorinated electrode on space charge behavior in polyethylene. In this study, the space charge distribution inside polyethylene is measured by laser-PWP (Pressure Wave Propagation) method while altering electrode fluorination duration and fluorination temperature. The experimental results show that measured homocharge injection is increased in polyethylene to which a fluorinated semiconductive electrode is heat pressed. Attenuated Total Reflectance-Infrared (ATR-IR) spectroscopy and Scanning Electron Microscope (SEM) are also performed, revealing that the fluorinated layer of semiconductive electrode on the interface between polyethylene and electrode block impurities from entering polyethylene. The measured space charge distribution, being the planar average amount, also reveals impurity generation since heterocharge formation is observed. As such impurities are blocked, in the meantime the electrodes' homocharge injection remains un-affected, thereby the measured apparent charge is greatly increased.

Ultra-high molecular weight polyethylene (UHMWPE) possesses distinctive properties, but has an extremely low melt flow rate (MFR) of about zero, which makes it unsuitable for processing by standard methods for polymers. The aim of this paper was to investigate the tribological properties of two-component UHMWPE-based composites with different content of isotactic PP. The composites were fabricated by three methods: a) hot pressing of the powder mixtures; b) hot compression of granules; and c) 3D printing (FDM). It was shown that the UHMWPE-based composites obtained by extrusion compounding (hot compression of granules and 3D printing) in terms of the mechanical and tribological properties (wear resistance, the friction coefficient, Young's modulus, and yield strength) were superior to the ones manufactured by hot pressing of the powder mixtures. The most effective was the ‘UHMWPE+20% PP’ composite in terms of maintaining high tribological and mechanical properties and the necessary melt flow rate (MFR) in a wide range of loads. It was recommended as a feedstock for additive manufacturing of complex-shaped products (joint components) for friction units in orthopedics.

This paper presents the results of an investigation of the influence of the aluminum-powder concentration on the thermomechanical characteristics of the composites based on the high-density polyethylene. We show that use of a compatibilizer—maleic anhydride–polyethylene graft copolymer—in a mixture with high-density polyethylene has an influence on the regularity of variation of the thermomechanical curves. We study the influence of various cross-linking agents (dicumyl peroxide and sulfur) on the thermomechanical properties of composites. At a particular dicumyl peroxide and sulfur concentration, the composites might reside in three physical states: solid, highly elastic, and viscous flow.

The annual worldwide production of coffee exceeds 10 million tons, and more than 90% of this production is waste, including the husk. On the other hand, plastic consumption increases every year, and sustainable alternatives are necessary to decrease it. This work arises to solve these two problems, and seeks to produce products at an industrial level from polyethylene/coffee husk eco-composites. Both Low Density Polyethylene and High Density Polyethylene were used, and the amounts of coffee husk added as filler were 20 and 40 wt%. The composites were characterized by different morphological, thermal and mechanical techniques. Scanning Electron Microscopy images showed husk particles embedded in the polymer matrix, but with some gaps between the polymer and the filler, because no compatibilizer agent was used. The addition of large amounts of natural filler negatively affected the tensile strength and elongation at break, but increases eco-composites crystallinity, and hence, their Young modulus and hardness. The industrial applicability of the eco-composites was verified through the production of five different consumer products by extrusion and injection processes, using mixtures with 40 wt% coffee husks. All products were obtained without significant defects. If only 3.25 wt% of the polyethylene products produced each year in Colombia did so with the eco-composites developed in this work, all the coffee husk produced in the country would be used, and the emission of about 5.390 million m3 of greenhouse gases would be avoided.

A method for the introduction graphene into high-pressure polyethylene (HPPE) has been developed. Samples of graphene-HPPE were obtained with the content of graphene filler: 0.25%; 0.5%; 1.0%; 1.5%; 3.0%; 5.0% wt. The structural, morphological and deformation-strength properties of the obtained samples have been investigated. It was established that the increase of the elastic modulus value for the samples with the filler concentration of 3% wt and more.

Получены значения динамической вязкости битумного вяжущего с добавками низкомолекулярного полиэтилена в температурном интервале 60…160 °С. При введении полимерных добавок в дорожный битум вязкость битума повышается. Наиболее высокие значения динамической вязкости наблюдаются у полимерной добавки Вискодор - ПВ1, это ярко выражено при расходе 4 % добавки от массы битума и при температурах ниже 130°С. Добавка неокисленного низкомолекулярного полиэтилена Honeyvell Titan 7205 увеличивает вязкость в большей степени, чем добавка окисленного полиэтилена Honeyvell Titan 7686. Определены допустимые технологические температуры асфальтобетонных смесей с полимерными добавками на этапах структурообразования асфальтобетона. We obtained the values of the dynamic viscosity of bitumen binder with additives of polyethylene with low molecular weight in the temperature range of 60…160 °C. When polymer additives are introduced into road bitumen, the viscosity of bitumen increases. The highest values of dynamic viscosity are observed for the polymer additive Viskodor - PV1, this is clearly pronounced at the consumption of 4 % of the additive based on the mass of bitumen and at temperatures below 130 °С. The additive of unoxidized low molecular weight polyethylene Honeyvell Titan 7205 increases the viscosity to a greater extent than the additive of oxidized polyethylene Honeyvell Titan 7686. We determined as well the permissible technological temperatures of asphalt concrete mixtures with polymer additives at the stages of structure formation of asphalt concrete.

Objectives. To study the relationship between bending deformation and the change in the electrical resistance of carbon black polypropylene composites.Methods. Conductive polypropylene composites filled with carbon black UM-76 were investigated. The samples were deformed and kept under constant bending at temperatures of 20–155 °C.Results. The deformation of the samples led to a reversible increase in their electrical resistance, while subsequent holding of the samples in the deformed state was accompanied by an exponential drop in their electrical resistance. The average times and activation energies of the electrical relaxation of the deformed polypropylene composites were calculated (30–32 kJ/mol) and compared with similar characteristics of polyethylene composites (15–16 kJ/mol).Conclusions. The electrical resistance relaxation of deformed carbon black polypropylene composites at elevated temperatures is similar to their stress relaxation. The average times and activation energies of the electrical relaxation of deformed polypropylene composites are comparable with similar data on their mechanical relaxation. It was found that these electrical and mechanical phenomena are based on the same underlying physical processes.

The effect of nanofilles additives containing copper oxide nanoparticles stabilized by a polymer matrix of high-pressure polyethylene obtained by the mechanochemical method on features of the structure and properties of metal-containing nanocomposites based on isotactic polypropylene and high-pressure polyethylene was studied using differential thermal (DTA) and X-ray phase (XRD) analyzes. The improvement of strength, deformation and rheological parameters, as well as thermal-oxidative stability of the obtained nanocomposites was revealed, that apparently, is associated with the synergistic effect of interfacial interaction of copper-containing nanoparticles in the PE matrix with the components of the PP/PE polymer composition

Total thermal neutron cross section measurements serve as the primary means of validation for thermal neutron scattering kernels, an important quantity for neutron transport calculations. In an effort to improve the quality of thermal neutron scattering kernels, researchers at Rensselaer Polytechnic Institute (RPI) designed and constructed a polyethylene based cold moderation system to enhance neutron flux below 10 meV when coupled with the Enhanced Thermal Target (ETT) at the RPI Gaerttner LINAC. The final design yielded an increase in sub-thermal neutron flux (below 10 meV) by a factor of 4.5 for a moderator temperature of 37.5 K relative to the ETT alone. A further increase to a factor of 6 is expected after a minor geometry modification and decrease in polyethylene temperature to 25 K. This novel capability will be used to conduct total thermal neutron cross section measurements from 0.0005–10 eV for different materials including moderator materials.