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The reliability of thermal regulation systems is crucial for ensuring the stability of condensed-mode gas-phase fluidized bed reactors (FBRs) used in the production of linear low-density polyethylene (LLDPE). However, studies reporting on the practical industrial control engineering of such reactors relying on thermal equilibrium mechanisms are scarce. This study presents a thorough analysis of a hot thermoregulating water (TRW) valve-jamming incident and interprets the related phenomena and parameter changes. The effect of the catalyst activity and variations in the liquid-phase quantities on the TRW valve action are investigated in depth, and a general explanation is provided by analyzing typical distributed control system data trends and proven deductive reasoning. Results indicate that the polymerization stability is maintained by two thermal pathways. The first pathway is related to the latent (condensate)/sensible heat (gas) extraction and polymerization heat of the materials, and the second is associated with the TRW system, specifically the cold and hot TRW branches. These pathways exhibited synergistic bidirectional effects. Finally, a series of innovative measures are proposed for internal and external operations to fully prevent and respond to TRW valve malfunctions and maintain overall polymerization stability. This study enhances the dependability of linear low-density polyethylene production through advanced process optimization utilizing the Unipol prototype and offers perspectives on system engineering for polyethylene production processes. [ABSTRACT FROM AUTHOR]

The modified atmosphere packaging films based on polyethylene nanocomposites reinforced with perlite nanoparticles were prepared using a blow molding machine. The perlite particles were first reduced to nano dimensions using an abrasive mill, then the porosity of nanoperlite was increased to improve their efficiency in absorbing ethylene gas. For this purpose, 6 normal sodium hydroxide solution at 50°C temperature was used. Finally, perlite nanoparticles were modified by polymethyl hydrogen siloxane silane compound. In each of the stages of grinding and modifying the perlite surface, the necessary tests including dynamic light diffraction test, nitrogen absorption test and ethylene gas absorption test were performed using gas chromatography method. The results showed that the size of perlite particles was reduced to 500 nm by using an abrasive mill, and the surface modification process increased the specific surface area of perlite by 10 times. Based on this, the amount of ethylene gas absorption in perlite nanoparticles with modified surface increased up to 3 times compared to normal perlite. The results of the gas chromatography test showed that the nanocomposite film based on polyethylene reinforced with 6% by weight of modified perlite nanoparticles has several times the efficiency in absorbing ethylene gas compared to the potassium permanganate sachets The results of the mechanical properties tests of nanocomposite film in comparison with pure polyethylene film showed that nanocomposite film has higher properties than pure polyethylene. The results of shelf-life tests of green tomatoes packed in nanocomposite film based on polyethylene reinforced with modified nanoperlite showed that green tomatoes can be stored for two months using the prepared modified atmosphere packaging. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF) is one of the established thermoplastics with inherent piezoelectric characteristics. In the past two decades, a lot of work has been reported on the use of virgin Polyvinylidene fluoride thermoplastics for sensing applications. But hitherto little has been reported on 3D printing of secondary (2°) recycled Polyvinylidene fluoride as a smart energy storage device (ESD). This work is focused on exploring the possibilities for 3D printing of smart energy storage device comprising of Polyvinylidene fluoride having (melt flow index (MFI) 30 g /(10 min) as per ASTM D 1238) reinforced with MnO2, graphite, ZnCl2, and N H 4 Cl in different weight proportions to form a feedstock filament for fused deposition modeling (FDM) in the first stage. The MFI of Polyvinylidene fluoride composites reinforced with MnO2, graphite, ZnCl2, and N H 4 Cl (34.095, 8.480, 42.982, 11.807 g /(10 min) respectively) was ascertained for possible 3D printing on FDM. The results suggest that even with an acceptable MFI of prepared 2° recycled Polyvinylidene fluoride, the same was not printable. Further for possible 3D printing on FDM, low-density polyethylene (LDPE) was blended in a Polyvinylidene fluoride matrix, and successful 3D printing-based energy storage device was prepared in the second stage. The study also highlights the mechanical, and morphological properties of Polyvinylidene fluoride composites have been improved after processing with a twin-screw extruder (TSE) by using different input parameters (screw temperature (T), screw speed (S), and load (L)). Overall, the study suggests that the proportion of LDPE, MnO2, graphite, ZnCl2, and N H 4 Cl has a significant effect on the rheological, mechanical, and morphological properties. The results have been supported with scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transformed infrared spectroscopy (FTIR) analysis. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effect of recycling process on the molecular structure, viscoelasticity and foaming behavior of low density polyethylene (LDPE). A series of LDPE samples with different recycling process was prepared by multiple extrusion using a twin-screw extruder. The molecular weight distribution (MWD) was characterized by gel permeation chromatography (GPC). Wider MWD indicated the generation of higher molecular weight products. Small-amplitude oscillation rheology showed reduced loss factors, indicating that the chain entanglement was more difficult to relax. Moreover, nonlinear viscoelasticity was investigated using elongational rheology and molecular stress function (MSF) model. The results showed a steeper strain hardening exhibited in recycled LDPE. The correlated parameter β in the MSF model indicated that the recycling did not significantly change the branches regularity in LDPE, while the increasing f max 2 , the other correlated parameter, indicated that the chain entanglement was enhanced, which was corresponded to the improvement of high molecular weight component. The foaming results revealed that the recycled LDPE had finer cellular structure and higher nucleation density. Moreover, despite adding PP and active CaCO3 to simulate the impurities, the foamability loss of these mixed samples was well restricted and still valuable. Recycled LDPE is instead better than its corresponding virgin one in foaming performance, exhibiting the application potential for further developments. [ABSTRACT FROM AUTHOR]

Interlocking paving bricks were produced with plastic wastes and sand using heating technique without other cementing or binding agent and water. Waste single-use plastics - polyethylene terephthalate (PET) bottles and low density polyethylene (LDPE) sachet water films used respectively were sourced from dump site, washed, air dried, melted and mixed with sand of not more than 2 mm particle size to produce interlocking paving brick (IPB). Sand-plastic mix ratios of 1:1, 1:3 and 3:1 and metal mould of 190 × 90 × 90 mm dimension were used. The compressive strength, flexural tensile strength, abrasion and water-absorption test results showed that IPB from LDPE-sand composite has better mechanical performance than IPB from PET-sand composite for all the mix ratios. The IPB from LDPE-sand composite of 3:1 mix ratio had a compressive strength of 31.11 N/mm2 and water absorption of 0.33% of its dry weight whereas its PET counterpart had compressive strength of 13.1 N/mm2 and water absorption of 0.5%. Scanning electron microscope (SEM) and abrasion results also showed that LDPE had better compatibility with sand particles. Waste single-use plastics can be used to produce high quality interlocking paving brick without cement and water and as well reduce the menace of waste PET bottles and LDPE films in our environment. [ABSTRACT FROM AUTHOR]

This document describes a collection of patents related to elastomers and plastics. The patents cover a wide range of topics, including methods for enhancing bonding of thermoplastic composites, rubber compositions with carbon nanotubes, and manufacturing methods for low-density polyethylene. The document provides summaries of each patent, including information about the inventors and abstracts of the patents. [Extracted from the article]

Bubble nucleation and growth were investigated in low density polyethylene (LDPE) using nitrogen (N2). The solubility and diffusivity of N2 in low density polyethylene were determined by a magnetic suspension balance (MSB) system. The bubble nucleation and growth during foaming was assessed using a visualization batch foaming system. It was observed that the increase in temperature and pressure decrement, decreased the bubble density, respectively. The bubble size during the foaming was also studied through numerical model and the effect of various simulation variables on the bubble growth was investigated. It was concluded that the numerical model could predict the foaming process. Moreover, according to the bubble pressure profile, the N2diffusion are formative factors in controlling the bubble growth. [ABSTRACT FROM AUTHOR]

The exceptional low permeability to oxygen and water of PVDC and the retention of barrier properties to oxygen even in humid conditions explain its success for packaging in food industry as barrier layer in Polyolefins (PO) multilayer films, whose contribution to the reduction of food waste is largely recognized. Several chemical recycling technologies have emerged in the recent years that, together with methodologies based on separation of layers by the use of solvents, will strongly increase in a near future the extent of recycling of multilayer films, including the PVDC-containing ones. At the same time, it is generally accepted that for several years these technologies will be complemented by the now dominating mechanical recycling. A lack of detailed study in the literature and a general confusion between very different PVDC grades, with and without internal stabilization, led to the idea that the dehydrochlorination of PVDC would cause a low quality of the recyclate obtained by mechanical recycling of PO in presence of PVDC and a corrosion risk for the equipment. In this study, the effect of a stabilized PVDC grade developed for coextrusion, at concentration typical of real life PO mix for mechanical recycling and in suitable condition, has been investigated in a pilot scale extruder and corrosion tests were performed. In conclusion, quantities of PVDC to be found in PO streams for mechanical recycling are compatible with a PO recyclate of excellent characteristics, even at extrusion temperatures as high as 220°C, with no damage to the PO structure, with only minimum discoloration, that can be mitigated by relatively low quantities of additives of general use in PO extrusion, and with no risk of corrosion of the equipment. [ABSTRACT FROM AUTHOR]

This study focuses on the development of low-density polyethylene matrix nanocomposite films for food packaging industry and aims at improving low-density polyethylene oxygen barrier properties while maintaining other relevant characteristics, such as processability, easy post-processing, optical and mechanical properties. low-density polyethylene nanocomposites, with 1 and 2.5 wt.% nanoclay (NC) and also compatibilized with 5 wt.% polyethylene grafted with maleic anhydride (PE-g-MA), were prepared and used to produce blown films. The nanocomposites were characterized in terms of their morphology, thermal, rheological, mechanical, barrier and optical properties, through scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), rheological measurements, tensile tests, water vapor transmission, oxygen permeability tests and spectrophotometry. The results demonstrated good NC dispersion in the polymer matrix and decreased oxygen permeability in the compatibilized nanocomposite films. All the other properties did not significantly change when compared to neat low-density polyethylene. Overall, the film properties were improved with the added nanoclay and PE-g-MA and, have potential for food packaging. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of O2-absorbing sachets into different packages polyethylene terephthalate (PET – E1), low density polyethylene (LDPE – E2), and PET/LDPE (E3) on the quality of minimally processed soybean sprouts (MP-sprouts). The MP-sprouts were stored up to 12 days and characterized for physicochemical, microbiological and sensory attributes. The O2-absorbing sachet showed changes during exposure to the environment by the formation of amorphous iron hydroxide, which was observed by the analysis of functional groups and XRD. The packaging used in the study showed high transmittance and clarity, and low Haze, being a good feature for storing the MP product. All packaging systems showed an increase in the volume of absorbed oxygen (cm3) up to 9 days of storage. The physic-chemical characteristics of the MP-sprouts stored for 12 days were preserved in the different packages, showing no difference regarding the use of the O2-absorbing sachet. The O2-absorbing sachet not influenced the quality of MP-sprouts during the stored (12 days). The best visual aspect was observed in PET package (with and without O2-absorbing sachet) being classified as excellent, without color change. The MP-sprouts also fulfilled the microbiological quality standards and presented 75.11% acceptability and 72.40% purchase intention. [ABSTRACT FROM AUTHOR]

The primary objective of this research paper is to control the material and process defects in polymer melt extrusion film casting (EFC) process for linear chain architecture polyethylene (PE) resins through polymer blending methodology. Extrusion film casting is a well-known industrially important manufacturing process that is used to manufacture thousands of tons of polymer/plastic films/sheets and coated products. In this research, the necking defect in an EFC process has been studied experimentally for a linear low density polyethylene (LLDPE) resin and attempts have been made to control its necking by blending in a long chain branched (LCB) low density polyethylene (LDPE) resin. The blending methodology is based on the understanding that a LDPE resin displays enhanced resistance to necking as compared to the LLDPE resin. It is found that added LDPE resin enhances necking resistance for the primary LLDPE resin. Further, as the LDPE concentration increases in the blend formulation, the necking is further reduced as compared to pure LLDPE. Analogous to past studies on EFC of linear and long chain branched architecture containing PEs, it is observed that as the LDPE is increased in the blend formulations, the formulations displayed enhanced melt elasticity and extensional strain hardening in rheological studies. It is concluded from this study that polyethylene resins having linear chain architecture can be made amenable to enhanced resistance to necking using appropriate amount of a long chain branched resins. Finally, process defects such as the draw resonance onset could be shifted to higher draw ratios as the LDPE level is increased in the LLDPE-LDPE blend formulation. [ABSTRACT FROM AUTHOR]

The current study reviews the viability of various fibre-polymer composites and treatment techniques along with the intricacy involved in improving the rotational moulding process. It is a method used in the manufacturing of hollow plastic items free from stress. As the rotational moulding process has gained prominence in a variety of crucial applications in recent years, a detailed analysis of this technique is important. For this reason, an exhaustive review of various fibres and polymers used in rotational moulding along with different pre-treatment techniques for improving the processability has been carried out and categorised into three sections. The first section deals with the type of polymers which are used for the process along with their nature and suitability for rotational moulding. The second section deals with the study of different fibres that have been blended with the polymers. The last section of the review discusses the different fibre treatment techniques which can be used to improve polymer-fibre compatibility. From a wide range of polymers used, it has been observed that the ease of processability of linear low-density polyethylene makes it the most suitable grade for rotational moulding. It can also be noticed that artificial fibres provide good mechanical properties compared to natural fibres but being eco-friendly and having low cost, natural fibres are more vital in the application. It is evident from the review that fibre pre-treatment enhances the polymer-fibre compatibility which improves the mechanical properties of the rotationally moulded products. Further, it can be concluded from the literature review that an adequate variety of polymer and fibre along with fibre treatment techniques can make an important contribution to the rotational moulding process. [ABSTRACT FROM AUTHOR]

For more information on Toppan's mono-material packaging solutions, visit https://www.toppan.co.jp/living-industry/packaging/english/products/mono-material flexible packaging/ Toppan plans to expand sales of this and other mono-material packaging products as it works to contribute to a sustainable global society. Toppan has taken advantage of its proprietary GL BARRIER technologies to overcome the difficulty of vapor deposition on PE and deliver barrier performance superior to that of existing PE mono-material packaging (Figure 2). Features of PE mono-material barrier packaging for liquids Recyclability provided by PE mono-material composition Superior recyclability has been achieved by employing a packaging material composition that consists only of PE. [Extracted from the article]

Ethylene acrylic acid copolymer (EAA) is widely used as tie-layer in multilayer film structures containing aluminum foil. EAA provides adhesion between the foil and rest of the film structure. It can be used alone or as a blend with low density polyethylene (LDPE), ordinarily between 20 and 50%. However, blending EAA and LDPE does not always produce desirable results. From time to time, a clear film becomes hazy as the EAA content is increased. At the same time, the adhesive strength to foil decreases. This study focuses on elucidating the mechanism behind the high haze and poor adhesion associated with EAA/LDPE blends and on determining factors that can optimize blend performance. The results from this study indicate that immiscibility, not viscosity mismatch, is the dominant factor affecting EAA/LDPE blends. In general, EAA with low acid content is more compatible with LDPE than EAA with high acid content. Processing parameters, such as extruder RPM and melt temperature, can also be selectively used to improve the blend haze or layer adhesion. [ABSTRACT FROM AUTHOR]

In this study, silane grafted and moisture cross-linked low density polyethylene nanocomposite foams were prepared by melt mixing and batch foaming process and the effects of silane content, nanoclay content, foaming agent concentration and clay type (clay modified with vinyltriethoxysilane (VTES) and amino-propyltriethoxysilane on foaming efficiency and foam properties were investigated. The morphology and the efficiency of silane modification of modified clay were characterized by series of tests, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The results of Fourier transform infrared and thermogravimetric analysis showed that the silane modifiers were bonded to the surface of nanoclay through both physical and chemical bonds. According to XRD, these modifiers caused characteristic peak of clay to shift to lower angles, and make an increase in basal spacing. Gel content, density, scanning electron microscopy, compression, creep and rheological tests were used to determine the effect of different parameters on properties of cross-linked polyethylene foams. Results indicated that silane content has the significant effect on stress-strain behavior in compression mode. Compression set and creep deformation were affected by cell size and gel content. Furthermore, the rheological properties including complex viscosity, storage and loss modulus of unformed samples increased with the addition of silane and nanoclay content. [ABSTRACT FROM AUTHOR]

The main goal of this work was to assess the technical feasibility of palm rachis (PR) as a reinforcing agent in the production of wood–plastic composites. Recycled linear low-density polyethylene/PR fiber composites were prepared at constant content (3 phc (per hundred compounds)) of maleic anhydride-grafted polyethylene as compatibilizer by melt blending method utilizing a two-roll mill and compression molding. The effect of nanosilica (NS), nanoclay (NC), and hybrid nanoparticles (NSNC) at different concentrations (2, 4, and 6 phc) on mechanical, physical, thermal, and morphological properties was investigated. The results of mechanical properties measurements demonstrated that when 6 phc NS, 4 phc NC, and 4 phc NSNC were added, tensile, modulus strength, and hardness reached their optimum values. At a high level of NC loading (6 phc), the increased populace of NC layers led to agglomeration and stress transfer gets restricted. Elongation at break and Izod impact strength were decreased by the incorporation of different nanoparticles. Water absorption and thickness swelling of prepared composites were found to decrease on the incorporation of NS and NC. In addition, the thermal stability showed slightly improved by the addition of nanoparticles, but there are no perceptible changes in the values of melting temperature by increasing the content of NS and NC or NSNC. Scanning electron microscopy study approved the good interaction of the PR fibers with the polymer matrix as well as the effectiveness of NS and NC in the improvement of the interaction. The finding indicated that wood–plastic composite treated by NS had the highest properties than other composites. [ABSTRACT FROM AUTHOR]

The contact with ultraviolet rays coming from sunlight causes color changes and deterioration in the main chain structures of composites in outdoor applications and affects the physical and mechanical properties of composite materials negatively. Photodegradation can be slowed and the mechanical strength of composite structures can be improved with adding photostabilizers in polymer matrix production. In this study, we modified low-density polyethylene (LDPE) polymer with an amine light stabilizer (Chimassorb 944), a light absorbent (Tinuvin 326), and an antioxidant (Irganox 1010) and then reinforced with jute fabric (JF). We examined the effect of protective additives, which are used to reduce the harmful effects of sunlight, on JF-reinforced LDPE composites. The color change, physical, and mechanical properties of the composites were determined after 120- and 240-h accelerated aging processes. The results indicate that both the antioxidants and the amine light stabilizers were more effective photostabilizers for JF-reinforced LDPE composites than the absorbents. [ABSTRACT FROM AUTHOR]

Rice husk ash (RiHA) was employed as the bio - originated and inexpensive filler prepared from agricultural wastes for reinforcing high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). X-ray fluorescence (XRF) spectroscopy showed ∼80.82% for the silica content of RiHA as well as the values of other components present in this bio-based filler. The composites were obtained via melt mixing followed by the compression molding by the hot press forming. Characterization of the composites by FT - IR spectroscopy revealed that the filler has the sheer effects on the vibrational bands of the polymers. The usage of X-ray diffraction (XRD) analysis to investigate the d - spacing values and the crystallinity of the samples, exhibited the increase of d - spacing upon reinforcing the polymers with RiHA. The scanning electron microscopy (SEM) images showed an average size of 32 µm for the irregular RiHA particles which uniformly dispersed in the polymeric matrices. The energy dispersive X-ray (EDX) analysis displayed C, O, and Si as the main constituting elements of the composites and alternatively confirmed the well dispersion of the filler particles into the polymer matrices. The mechanical measurements showed the significant improvements in Young's modulus, yield stress, and hardness results of the polymers after reinforcing with the rice husk ash. For example, Young's modulus of HDPE was increased ∼15% after incorporating 7 wt.% of RiHA into this polymer. These mechanical properties of the polymers were increased upon increasing the RiHA content, while the parameter of elongation at break was decreased. [ABSTRACT FROM AUTHOR]

Greenhouse culture usually requires a controlled environment for optimum plant growth and production. However, regular plastic films used for their coverage create an uncontrolled microclimate, especially in areas with harsh climatic conditions. Three low-density polyethylene (LDPE) films, a commercial ordinary film, a three-layer film, and a monolayer film were used as a greenhouse covering materials to study its behavior in presence of a cultivar and harsh climatic conditions. They were exposed to natural weathering and UV radiations in the semi-arid environment of a city located in northern Algeria. This study aims to investigate and compare the lifespan and deterioration of the materials used for a 5-month period to improve future greenhouse cultivation. Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectrophotometry (UV-vis) were used to study the aging and degradation of these films. FTIR 1030/2848 bands ratio was used to determine the chemical oxidation rate of each film. Visible changes in the material structure were also recorded during the aging process. Materials underwent photo and thermo degradation, leading to chemical and mechanical changes. The monolayer film has suffered more mechanical degradation than the multilayer films, leading to its total crumbling in a short lifetime. The three-layer and ordinary films were more resistant and showed approximately the same behavior towards the rough climatic conditions. Furthermore, the UV-visible spectrum indicated a high loss of transparency of the polyethylene films during their use. The two studied multilayer films seem more adequate for greenhouse culture under the semi-arid regions. [ABSTRACT FROM AUTHOR]

The nanocomposites of high-density polyethylene, low-density polyethylene, polypropylene, and poly(vinyl chloride) reinforced with Azadirachta indica wood flour (WF) and different amounts of the organomodified nanoclay and titanium dioxide (TiO2) nanopowder were produced by melt-blending process followed by compression molding. Polyethylene- co -glycidyl methacrylate (PE- co -GMA) was used as a compatibilizer. TiO2 nanopowder was synthesized by sol–gel method and characterized using transmission electron microscopy (TEM). The average size of the synthesized nano-TiO2 was 17.5 nm, which was confirmed both by TEM and X-ray diffraction (XRD) study. The distribution of nanoparticles in the nanocomposites was also examined by the XRD study. The surface modification of the TiO2 nanoparticles by organic surfactant cetyl trimethyl ammonium bromide and their interaction with the wood and the polymer were studied by Fourier transform infrared spectroscopy. Incorporation of compatibilizer PE- co -GMA, nanoclay, and nano-TiO2 significantly influenced the mechanical and thermal properties of the WF-reinforced composites. Wood polymer composites (WPC) reinforced with nanoclay and nano-TiO2 showed improved tensile strength, tensile modulus, flexural strength, flexural modulus, and hardness. Maximum improvement in mechanical properties was shown by WPC loaded with 40 phr WF, 2 phr nanoclay, and 2 phr of nano-TiO2. On inclusion of organically modified nanoclay and nano-TiO2, the WPC samples showed lower water uptake and higher chemical resistance. The nanocomposites were further examined by TEM study and thermogravimetric analyzer. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) has high flammability and can be quickly burned under atmospheric conditions without leaving any residues. This study presents PE fibers produced by a novel modified melt spinning line to enhance mechanical and flame retardancy properties. Scanning electron microscopy equipped with energy dispersive X-ray, thermogravimetric analysis, limiting oxygen index, micro combustion calorimeter and tensile tests were performed to reveal morphological, thermal and mechanical characteristics of the fibers. An organic phosphorus additive was used to provide flame retardancy in addition to mechanical performance in one-step production. Subsequently, the produced fibers were subjected to the hot drawing, increasing modulus values from 135 MPa to 2.8 GPa. In addition, phosphorus-treated fibers exhibited a limiting oxygen index (LOI) value of 21.5, leaving some residue at 600°C. Furthermore, a decrease in the peak heat release rate (pHRR) was observed in all samples compared to the control sample for the micro combustion calorimeter (MCC) test. Looking at the decrease in heat release (HR), the best result belongs to zone II with 50 and 95°C produced at 1000 m/min take-up speed for the samples. Moreover, about 23%, 23%, and 18% decreases were observed in HR capacity, pHRR, and total HR values, respectively. The modified spinning system is capable of continuous production of flame retardant linear low-density polyethylene (LLDPE) fibers, which can find widespread applications in aviation, automotive, and defense industries. [ABSTRACT FROM AUTHOR]

The enormous rise in plastic waste leads to severe environmental issues and complete removal is a quiet challenge. The entire world focuses on finding new alternate for traditional conventional fuel. The waste low-density polyethylene is chosen as feedstock for the preparation of fuel from thermo-catalytic pyrolysis, considering the silica–alumina catalyst at a reaction temperature of 500 °C. From our previous study, the lower blends of waste low-density polyethylene exhibit a similar performance to diesel. However, brake thermal efficiency and oxides of nitrogen are not encouraging. Further improving combustion behaviour, the present research is carried out at different injection timings. The investigation is carried on standard injection timing of 23°bTDC and three retarded injection timings, namely, 21°bTDC, 19°bTDC and 17°bTDC. Retarded injection timing exhibits higher performance and lower unburned hydrocarbon, oxides of nitrogen and carbon monoxide emissions. However, smoke emission is increased due to the reduced heat release at all the considered test parameters. The result divulges that reduced performance and increased smoke at 17°bTDC due to the lack of burning rate. The combustion behaviour of 20% waste low-density polyethylene by volume at 19°bTDC is similar to that of diesel at 23°bTDC. Hence, the injection timing of 19°bTDC is preferred as an optimized condition for the test fuel 20% waste low-density polyethylene by volume. [ABSTRACT FROM AUTHOR]

Natural volatile antibacterial and anti-mycotoxin tea tree oil (TTO) with rice bran (RB) were used as a solid carrier for achieving a sustained release profile with high antimicrobial efficiency in polyethylene films. Acrylic acid (AAc) monomer was grafted onto a low-density polyethylene (LDPE) through melt blending using a Brabender Plasti-Corder. The low-density polyethylene-grafted acrylic acid (LDPE- g -AAc) was thoroughly characterized by attenuated total reflectance–Fourier transform infrared spectroscopy. LDPE and LDPE- g -AAc (80/20) were mixed with different contents of untreated RB and treated TTO/RB using melt blending to obtain sustainable composites, namely LDPE/LDPE- g -AAc/RB and LDPE/LDPE- g -AAc/TTO-RB, respectively. The effect of the addition of untreated and treated RB on the properties of biocomposites was assessed by using mechanical, barrier, and thermal properties. A prominent decrease in water vapor transmission rate occurred when adding 30 wt% of TTO/RB to LDPE/LDPE- g -AAc blend compared to virgin polymer. This decrease was due to the barrier effect of lignocellulosic material, particularly at high bio-filler content. The prepared biocomposites revealed good thermal stability when compared to virgin LDPE. Moreover, the biodegradability and antimicrobial properties of LDPE/LDPE- g -AAc/TTO-RB biofilms were enhanced with increasing TTO/RB contents from 10 phr to 30 phr due to the combination between LDPE- g -AAc and TTO. The obtained data revealed excellent possibility for using biopolymer grafted with antimicrobial TTO by adding RB for food packaging and biomedical purposes. [ABSTRACT FROM AUTHOR]

Linear low-density polyethylene (LLDPE) incorporated with single-walled carbon nanotubes (SWCNTs) by mistreatment casting technique. The result of various weight percentage loadings of SWCNTs on the swelling and electrical properties of LLDPE/SWCNTs nanocomposite also γ-irradiation effects had been investigated. It was found that, at low concentration, it uniformly disperses into an LLDPE matrix and provides LLDPE/SWCNTs nanocomposites with abundant improved electrical properties by nine orders of magnitude. Positive temperature coefficient of conductivity (PTCC)/negative temperature coefficient of conductivity (NTCC) was affected by the SWCNT contents. Transmission electron microscopy and scanning electron microscope techniques were used to investigate the dispersion of SWCNTs in the LLDPE matrix. Linear exceptional modification within direct current electrical conduction of percolative threshold-loaded LLDPE as a perform of γ-irradiation dose will be used as a nontoxic, easy, inexpensive, and sensitive method to evaluate the irradiation dose in range 10 Gy–1 kGy also can be used in fabrication of firing sensors with various ranges of temperatures. [ABSTRACT FROM AUTHOR]

Generally, polyamide cannot be used as film blowing material because of its unsuitable properties. In this study, polyamide 6 clay nanocomposite (cPA) and styrene maleic anhydride copolymer (SMA) were mixed in various ratios for the preparation of modified polyamide 6 clay nanocomposite SxcPAy resins by reactive extrusion. The S1cPA14 resin was blended with recycled maleic anhydride polyamide (rPA) to form the (S1cPA14)x rPAy resins. Finally, they were mixed with LDPE in 1:9 ratio to afford (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins, respectively, followed by film blowing and the analyses of the physicochemical properties of resins. The FTIR spectrum illustrated that the C=O symmetric and asymmetric absorption fingerprint peaks in the anhydride (-OC-O-CO-) group of SMA disappeared and the new characteristic absorption peak of-CO-N-CO- of imides was observed. The anhydride functional group of SMA underwent reactive extrusion with the terminal amino group of cPA to generate the imides structure. The thermal properties showed that the glass transition temperature and crystallinity of SxcPAy and (S1cPA14)x rPAy resins increased with increasing SMA and S1cPA14 contents. The Tg (85.4.0°C) of (S1cPA14)12 rPA1 resin were enhanced significantly, with 30°C higher than cPA. In terms of tensile mechanical properties, S1cPA14 test pieces demonstrated the highest Young's modulus and tensile strength. After mixing with LDPE, the tensile mechanical properties of (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins and films were both higher than that of LDPE. ((S1cPA14)12 rPA1)1LDPE9 film shown the best tensile properties and barrier performance compared with other films due to the optimal rPA content could assisted SMA as a better compatibilizer to improve the dispersion and compatibility of cPA in HDPE. It was worth noting that (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins were formed by film blowing at the processing temperature of 140°C followed by successful preparation of the film. [ABSTRACT FROM AUTHOR]

A simple, effective and inexpensive method was proposed to reuse ground tire rubber (GTR) powder by preparing a superhydrophobic surface via a molding process. The obtained superhydrophobic surface was based on low-density polyethylene (LDPE) / ground tire rubber (GTR) thermoplastic elastomers (TPEs) where the styrene-butadiene-styrene block copolymer (SBS) was used as compatibilizer and series sandpapers were used as templates. The mechanical properties, hydrophobic properties, surface morphology and self-cleaning property were investigated systematically. The results showed that both of the mechanical properties and superhydrophobicity could be greatly improved with a certain amount of SBS. The superhydrophobic surface based on molded LDPE/SBS/GTR (weight ratio = 40/15/60) TPE exhibited excellent superhydrophobicity (with a contact angle of 164.6° ± 3.0° and a tilt angle of 4.4° ± 1.9°). Furthermore, abundant tearing microstructure could be found obviously by morphology observation. Optical images indicated the surface possessed of low adhesion force and self-cleaning property. [ABSTRACT FROM AUTHOR]

This investigation highlights effective technology to convert crystalline silicon photovoltaic solar panel waste to composite products. The main problem with recycling photovoltaic modules is to economically separate and extract the materials in the laminated structure. This investigation was attempted to recycle c-Si photovoltaic modules using an unconventional method in which the cumbersome process of separating the materials in the module is avoided altogether. The aluminium frame, outer glass and junction box are removed mechanically and the rest of the c-Si PV module waste is powdered and blended with recycled polypropylene (PP) and Low Density Polyethylene (LDPE) each to make compression moulded tiles. A total of six compression moulded tiles were made. Three tiles from each base material blended in three blend ratios (0%, 10% and 20%) with the powdered PV module waste. The tensile strengths of the tiles were tested and compared. The results prove that tiles made with recycled PP as a base material show very low tensile strength. However, recycled tiles made by blending with LDPE show appreciable tensile strength of more than 8 MPa. These tiles may be used to make furniture. [ABSTRACT FROM AUTHOR]

The improvements of the thermal, mechanical, morphological properties of low-density polyethylene (LDPE)/nanoclay (NC) composites were investigated. Low-density polyethylene (LDPE) with different NC contents 2 wt.% (V f = 8%), 4 wt.% (V f = 15), and 8 wt.% (V f = 27) with a fixed particle size (300μm) were prepared by the melt mixing process. The thermal tests (thermal gravimetric analysis) were performed to monitor the thermal stability of LDPE composites. The mechanical tests such as tensile strength, Young's modulus, and strain at break were studied. The results of the thermal gravimetric analysis (TGA) display significant enhancement in thermal stability as the loading of NC increased in pure LDPE. The results showed that the NC fillers could effectively improve the mechanical properties of LDPE by comparison to pure LDPE, the tensile strength of LDPE/8 wt.% of NC are increasing by about 17% while Young's modulus is increased by about 39%. From DMA results, the storage modulus is enhanced with increasing of NC loading into the LDPE matrix. The results of SEM photographs indicate that the incorporation 8 wt.% of NC displayed the best particles dispersion in the LDPE matrix. [ABSTRACT FROM AUTHOR]

SOLUTION: Provided is a resin foam composed of a polyarylene sulfide resin-containing polyarylene sulfide resin composition and in which the resin foam is formed from a resin composition containing a polycarbonate resin in a ratio of less than 50 pts.mass for 100 pts.mass of polyarylene sulfide resin. The method includes an arranging step to arrange one sheet of a foam resin sheet between first and second molds, the foam resin sheet being formed by extruding and dangling a molten foam resin from a slit; and an expanding step to expand the foam resin sheet by subjecting the foam resin sheet to a reduced pressure suction. SOLUTION: A computer program allows a computer to execute processing of acquiring a kind of thermoplastic resin foam particles as a material of a thermoplastic resin foammolded article, information relating to strength of the thermoplastic resin foam molded article using the thermoplastic resin foam particles, and a shape of the thermoplastic resin foam molded article, and outputting information relating to physical properties of the thermoplastic resin foam molded article to be produced and an estimated amount relating to production of the thermoplastic resin foam molded article, on the basis of the acquired kind, the acquired information relating to the strength and the acquired shape. [Extracted from the article]

Heat Resistant Foam Body and Foam Member I Inventor(s): i Kodama, K., Saito, M. I Sources: i JP Pat.: 2020-172641 I Corporate/Assignee: i Nitto Denko Corp. Graph PROBLEM TO BE SOLVED: To provide a heat resistant foam body that has high heat resistance, excellent flexibility, and excellent stress distributing capabilities, and a foam member having the heat resistant foam body as a heat resistant foam layer. A ratio.rho.sub.0/.rho.sub.1 of density of the resin.rho.sub.0 and true density.rho.sub.1 of the resin foam particles is 2 to 20, and a ratio.rho.sub.1/.rho.sub.2 of true density.rho.sub.1 of the resin foam particles and bulk density.rho.sub.2 of the resin foam particles is 1.5 to 4.0. SOLUTION: In a resin composite body that includes a core material 1 composed of a resin foam and fiber-reinforced resin layers 2a and 2 b having a fiber baser material and a resin impregnating the fiber base material, a bead foam molding in which a border line between the adjacent resin foam beads 10 has a mesh shape on the surface is formed into the core material 1, and the fiber-reinforced resin layers 2a and 2 b are composed of a resin 22 containing a colorant and a glass fiber sheet 21, and color gradation by the colorant appears on the surface. SOLUTION: A foam particle contains a polycarbonate-based resin as a base material resin, in which the foam particle has a value within 2.5-12 m/times when an average bubble diameter of the foam particle is divided by a bulky multiple of the foam particle. [Extracted from the article]

Flex barrier and optical density (OD) are two unique properties for metallized films and aluminum foil. This study investigated the effect of flexing on barrier properties of a laminate comprising metallized films and aluminum foil, as well as OD and adhesive lamination process on the overall multilayer laminate performance. Three (3) barrier layers, namely aluminum foil, metallized polyethylene terephthalate (met OPET) film with a high OD, and standard metallized PET film(met OPET), were laminated with the same printing layer OPET and sealing layer linear low density polyethylene (LLDPE), into OPET/adhesive/foil/adhesive/LLDPE and OPET/adhesive/met OPET/adhesive/LLDPE structures. The oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) were measured before and after flexing. The aluminum foil centered laminate had an excellent oxygen barrier after the 20-cycle flexing test and failed to retain its oxygen barrier after the 270-cycle flexing. Compared to the aluminum foil centered laminate, the metallized film centered laminates were less affected by the flexing on the oxygen barrier. For all laminates, the water vapor barrier was less severely affected by flexing than the oxygen barrier. This study suggests that the ASTMF392 Gelbo D (20- cycle flexing) can determine if aluminum foil and metallized film centered laminates are resistant to flex-formed pinhole failures. A higher OD, a thicker film thickness and lamination process improved laminate's actual barrier, resulting in lower measured transmission rates versus that predicted using Henry's solubility law and Fick's diffusion law. The laminate's water vapor transmission rate is 55–74% lower than predicted. The oxygen transmission rate is 15–31% lower than predicted. [ABSTRACT FROM AUTHOR]

In this study, ethylene-vinyl acetate (EVA) copolymer-based blend foams with polyolefin elastomers (POEs), low-density polyethylene, or styrenic thermoplastic elastomers were prepared as a potential resilient material for reducing inter-floor noise. Various properties of EVA blend foams were measured in order to reveal the effects of EVA content and types of pair polymers consisting of EVA blend foams on dynamic stiffness, which is one of the key factors of resilient materials, in relation to hardness, specific gravity, and resilience. These properties had not been introduced by the construction industry until now. When the EVA/POE ratio was 20/80 and the foaming ratio was 210%, dynamic stiffness presented the lowest value at 5.97 MN m−3. However, when the resilience was <20%, dynamic stiffness was as high as 37.66 MN m−3 at an expansion ratio of 210% even when the specific gravity was low. [ABSTRACT FROM AUTHOR]

Ultra-high molecular weight polyethylene has a low X-ray attenuation, hence, the performance of the polyethylene implants used for joint replacements cannot be directly investigated using X-ray-based imaging techniques. In this study, the X-ray attenuation of polyethylene was increased by diffusing an FDA-approved oil-based contrast agent (Lipiodol ultra fluid) into the surface of the samples, and the suitability of this novel radiopaque ultra-high molecular weight polyethylene for clinical applications was examined. Different levels of radiopacity were created by controlling the diffusion parameters, and the level of radiopacity was quantified from computed tomography scans and reported in Hounsfield units. The physical, chemical and tensile properties of the radiopaque ultra-high molecular weight polyethylene were examined and compared to untreated and thermally treated controls. The results of this study confirmed that for the samples treated at 115°C or less the diffusion of the contrast agent did not significantly alter the crystallinity (p = 0.7) or melting point (p = 0.4) of the polyethylene. Concomitantly, the tensile properties were not significantly different from the control samples (p > 0.05 for all properties). In conclusion, the radiopaque ultra-high molecular weight polyethylene treated for less than 18 h at a temperature of 115°C or below is a promising candidate for joint replacement applications as it can be identified in a standard X-ray while retaining the tensile properties of clinically used radiolucent ultra-high molecular weight polyethylene. [ABSTRACT FROM AUTHOR]

Ultrahigh molecular weight polyethylene (UHMWPE) is an excellent property polymer, but its poor processability due to high melt viscosity limits the more wide-ranging application. To improve the processability of UHMWPE composites filled by calcium carbonate (CaCO3), a novel method is reported to modify CaCO3. PE wax coated on the surface of CaCO3 (PEW@CaCO3) can be prepared by acrylic acid–modified CaCO3 (AA-CaCO3) and PE wax. The crystallization and melting behavior of UHMWPE and its composites filled by CaCO3, AA-CaCO3, and PEW@CaCO3 was compared by differential scanning calorimetry. The processability of UHMWPE composites was characterized by torque rheometer. The effect of CaCO3, AA-CaCO3, and PEW@CaCO3 on the crystallization and processability of UHMWPE was discussed. [ABSTRACT FROM AUTHOR]

Guar gum hydrogels may be dried to form polymer films which have the potential for use as biodegradable alternatives to polymers such as low-density polyethylene. In this study, the tensile strength and tensile modulus of guar gel films having moisture contents ranging between 15% and 18% (wet basis) were measured at a strain rate of 1 mm min−1. Mean tensile strengths of the films ranged between 25 MPa and 40 MPa (dependent on composition) which is of similar magnitude to the tensile strength data for polyethylene and cellophane that are reported in the literature. The mean tensile modulus of the films (1.5–2.5 GPa) was higher than the tensile modulus values reported for low-density polyethylene but comparable to those for cellophane (3 GPa). [ABSTRACT FROM AUTHOR]

Thermally laminated foam boards, methods for making thermally laminated foam boards, apparatus for making thermally laminated foam boards, smaller foam pieces made from thermally laminated foam boards, methods for making smaller foam pieces from thermally laminated foam boards, parts made from thermally laminated foam boards, methods for making parts from thermally laminated foam boards, and tools for making parts from thermally laminated foam boards are disclosed. The multilayer foam structure can be obtained by coextruding a multilayer structure comprising at least one nonrecycled foam composition layer with at least one recycled foam composition layer, irradiating the coextruded structure with ionizing radiation, and continuously foaming the irradiated structure. Polyethylene resin foam particles having the following mixture as a base resin, and the DSC curve obtained by differential scanning calorimetry (DSC) of the polyethylene resin foam particles has one melting peak derived from the polyethylene resin. The non-foam material is narrower than the foam material and is positioned relative to the foam material such that the edges of the non-foam material are concealed by the foam material. A resin laminate 10 comprises: at least one expandable resin layer 11 containing a resin and a thermally expandable graphite; and at least one foamed resin layer 12 made of a resin foam, wherein the sum of the values obtained by multiplying the thicknesses of the expandable resin layers 11 by expansion ratios is equal to or greater than the total thickness of the foamed resin layers 12. [Extracted from the article]

Graphene (Gr) distribution in low-density polyethylene (LDPE) considerably increased thermal stability, thermal conductivity, mechanical properties, and flexural properties of LDPE/Gr composites. Addition of Grs to LDPE postponed the time for making the polymer brittle. High specific surface area and superior properties of Gr improved thermal stability, conductivity, storage modulus, and mechanical properties of composites. The electrical conductivity of LDPE/Grs composites upgraded owing to the thermal stability of Grs in LDPE matrix. In terms of rheology, the addition of Grs augmented viscosity of the LDPE matrix. Addition of Grs to LDPE nucleates crystallization by reducing the activation energy along with rising crystallization onset temperature. Adding Gr facilitated decreasing aggregation, expanded crystallinity, improved the local lattice order of LDPE/Grs, and advanced Grs contact with LDPE. Thus, on a macroscopic scale, Gr constrains mobility of polymer chains, causing a growth in stiffness and strength of the composite. The distribution of Grs in LDPE at micron size scale was verified by atomic force microscopy and other microscopic testers. With further Grs inclusions to LDPE, the activation energy reduced, Grs proceeded as nucleating agents throughout the crystallization of composites, and increased the enhancement of relative crystallinity of LDPE/Gr compounds. The percolation phenomenon of LDPE/Gr composite occurred about 0.5 wt% of Gr loading. Due to further addition of Gr to LDPE, the impermeability of oxygen through the conduit raised somehow the LDPE/Gr sample with 0.5 wt% Gr content, generated a sharp improvement, and dropped fuel permeation with about 37% in comparison with pure LDPE. [ABSTRACT FROM AUTHOR]

In this paper, biocomposite films were prepared by using recycled low density polyethylene from marine plastic waste and wheat straw micropowders from common agricultural wastes in northern China. In order to determine the optimal ratio, eight experimental groups were set up for comparative testing. For further improving the performance of the biocomposite film, the three-dimensional network skeleton construction and targeted repairing technology of the material were designed. The specimens were characterized by a HD camera, a universal examination machine, a research grade inverted microscope, and a thermogravimetric analyzer. The results indicate that the agglomeration of powders reduces the tensile strength of the material, and the elongation at break depends on the properties of the polyolefin matrix itself. The reinforced biocomposite film has a 13.7 MPa tensile strength and a 243% elongation at break. It has slightly better mechanical properties than ordinary materials, which can be used as an economical, thermally stable, and environmentally friendly material to manufacture new packaging and courier bags. [ABSTRACT FROM AUTHOR]

This study was undertaken to fundamentally understand structure–property relationship of blown films of linear low density polyethylene/low density polyethylene blends over the entire composition range via decoupling orientation effects from their intrinsic properties. Three different low density polyethylene blends with an octene Ziegler–Natta linear low density polyethylene resin were studied. The machine direction tear strengths of blown film of linear low density polyethylene/low density polyethylene blends went through a minimum as the low density polyethylene concentration increased, almost a mirror image of the melt strength curve for these blends. The machine direction tear decreased significantly up to 40% low density polyethylene, much sharper decrease compared to decrease in intrinsic tear suggesting orientation effects dominating the machine direction tear behavior. The decrease in the dart impact and puncture energy was also due to both an increase in the machine direction orientation, and a decrease in the intrinsic toughness due to decrease in the tie chain concentration, as the low density polyethylene content increased. [ABSTRACT FROM AUTHOR]

A method of quantitative analysis of polypropylene/linear low density polyethylene blends was determined by using differential scanning calorimetry. The samples were prepared by means of extrusion process. The method of quantitative analysis was based on the principle that the melting enthalpies of the components in the mixture are proportional to their amount, but it has been found that the presence of two polymers in the blend has influence on the crystallization of its components. Previous studies seemed to neglect this phenomenon, so a linear correlation allowing to eliminate discrepancies between calculated and actual quantitative blend composition has been developed. This approach was proven to be more accurate than earlier directly proportional enthalpy—quantity dependence. [ABSTRACT FROM AUTHOR]

The effect of microcrystalline cellulose (MCC) on the thermal properties (melting and crystallization temperatures and percentage crystallinity) and degradation of low density polyethylene (LDPE)–MCC blends were investigated. Weight percentages of MCC were varied at 0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt%. The thermal properties of the composites were studied using differential scanning calorimetry while the degradation test was carried out using soil burial method; the weight loss of LDPE/MCC composites was measured and analyzed over a period of 120 days. It has been found that the addition of MCC to LDPE increased the crystallization temperature from 99°C to 103.5°C and decreased the melting temperature from 117°C to 113.6°C. A rule of a nucleating agent has been given as an interpretation to this increase in the crystallization temperature and intensity of crystals by the increase of MCC content. The dramatic reduction was in the percentage crystallinity where the value reduced from 58% for neat LDPE to about 11% for LDPE/30 wt% MCC. On the other hand, the addition of MCC has a little effect on degradation of LDPE; the weight loss did not exceed 1.5% over a period of 120 days. It seems that even at high MCC concentration, LDPE long carbon chains restrict and increase the resistance to microorganism attack and hence, reduce the hydrolysis and degradability. [ABSTRACT FROM AUTHOR]

This work was intended to provide an understanding of the effect of microcrystalline cellulose (MCC) on the mechanical properties of low-density polyethylene (LDPE). The impact resistance and the tensile properties of low-density LDPE/MCC composites were investigated. The weight fraction of MCC was varied at (0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt%). The obtained blends were then used to prepare the required tensile and impact testing samples by hot compression molding technique. It has been found that MCC has a strong influence on the mechanical properties of LDPE. At a low MCC weight fraction, there was a little improvement in the ultimate strength, fracture stress, and elongation at break, but at a high MCC weight fraction, the tensile properties were deteriorated and reduced significantly. The addition of 1 wt% MCC to LDPE enhanced the mentioned properties by 10, 25, and 6%, respectively. While at 30 wt% MCC, these properties were lowered by 36, 25, and 96%. The elastic modulus of LDPE composites was improved on all MCC weight fractions used in the study, at 20 wt% MCC, an increase in the elastic modulus by 12 folds was achieved. On the other hand and compared with the impact strength of pure LDPE, the addition of MCC particles enhanced the impact strength, the highest value obtained was for LDPE composites filled with 10 wt% MCC where the impact strength enhanced by two folds. [ABSTRACT FROM AUTHOR]

Uniform foams (UF) and density graded foams (DGF) were produced by using similar or different temperatures on both sides of a compression molding system. The samples were produced using linear low density polyethylene as the matrix and activated azodicarbonamide as the chemical blowing agent. Morphological properties of the produced samples were analyzed via scanning electron microscopy to relate them to their mechanical properties. In particular, flexural and impact properties are reported for samples produced under a range of temperatures (140–200°C) and blowing agent concentration (0.7–1.0 wt%). The experimental results showed that a significant difference can be obtained in flexural modulus (up to 17%) and impact strength (up to 48%) depending on the side the stress is applied on. In all cases, the DGF showed better mechanical responses than UF of similar relative density for the range of conditions tested. [ABSTRACT FROM AUTHOR]

Antimicrobial coated films were produced by an innovative method that allowed surface modification of commercial low-density polyethylene films so that well-defined antimicrobial surfaces could be prepared. A Pluronic™ surfactant and a polystyrene-polyethylene oxide block copolymer were employed to develop modified materials. The Pluronic™ surfactant provided a more readily functionalised film surface, while block copolymer provided a reactive interface which was important in providing a route to silver nanoparticles that were well adhered to the surface. Antimicrobial films containing silver were manufactured using a spray coater and the amount of silver used for coating purposes varied by the concentration of the silver precursor (silver nitrate) or the number of silver coatings applied. Potential antimicrobial activity of manufactured silver-coated low-density polyethylene films was tested against Pseudomonas fluorescens, Staphylococcus aureus and microflora isolated from raw chicken. The microbiological and physicochemical quality of chicken breast fillets wrapped with silver-coated low-density polyethylene films followed by vacuum skin packaging was also assessed during storage. Antimicrobial activity of developed silver-coated low-density polyethylene films was dependent (p < 0.05) upon the concentrations of silver precursor and the number of silver coatings used. Better antimicrobial activity against P. fluorescens, S. aureus and chicken microflora was observed when the concentration of silver precursor was 3% and the spray coating deposition of silver was repeated four times. Use of silver-coated low-density polyethylene films extended (p < 0.05) shelf life of chicken breast fillets and enhanced (p < 0.05) oxidative stability compared to control films. Results indicated that silver-coated low-density polyethylene films could potentially be used as antimicrobial packaging for food applications. [ABSTRACT FROM AUTHOR]

The effect of cellular microstructure and density of low-density polyethylene (LDPE) foam during the compressive deformation were evaluated. Progressive foam cell structure deformation at crosshead speed of 10 mm/min was closely monitored and captured using a portable digital microscope with the assistance of a proposed coating technique to enhance contrast of the foam cells. Results revealed that higher density foam, LDPE1.0, experienced higher compressive stress than the LDPE0.5 foam. It was believed that thicker cell walls in the LDPE1.0 foam contributed to the foam stiffness and higher stress was required to impose cell bending, buckling, and collapse. It was also discovered that the existence of larger cells within a group or cluster of small cells in the LDPE1.0 foam acted as stress concentration points and initiated the formation of shear bands in the foam cells deformation mechanism. The extent of compressive strain on the foam cells were also investigated, and results showed that cells undergo lower compressive strain compared to the actual deformation level given directly by the machine crosshead. Cells located in the middle section of the foam recorded a strain of about 13% when the bulk foam was deformed at 20% strain. The success in capturing the actual cell strain using the proposed coating technique proved that with the right improvisation, the micromechanical deformation of optically challenged white polyethylene foam samples can be monitored effectively using optical microscopy. [ABSTRACT FROM AUTHOR]

Low-density polyethylene single-polymer composites (SPCs) reinforced with sandwiched ultrahigh-molecular-weight polyethylene woven fabric were prepared by insert injection molding. The process combines aesthetic and processing advantages. A processing temperature window (135–155°C) of a very short cycle time (less than 30 s) could be realized. The mechanical properties and morphologies of the samples were evaluated. The results suggested that the polyethylene SPCs were prepared successfully with concurrent increases in flexural strength (∼57%), tensile strength (∼164%), and impact strength (∼69%). The effects of different processing parameters including the nozzle temperature, injection pressure, injection speed, and the holding time were discussed. Numerical simulation results were used in the analysis. [ABSTRACT FROM AUTHOR]