Polyethylene Membrane Research Articles

Fabrication and Investigation of PE-SiO2@PZS Composite Separator for Lithium-Ion Batteries.

Commercial polyolefin separators exhibit problems including shrinkage under high temperatures and poor electrolyte wettability and uptake, resulting in low ionic conductivity and safety problems. In this work, core–shell silica-polyphosphazene nanoparticles (SiO2@PZS) with different PZS layer thicknesses were synthesized and coated onto both sides of polyethylene (PE) microporous membranes to prepare composite membranes. Compared to pure silica-coated membranes and PE membranes, the PE-SiO2@PZS composite membrane had higher ionic conductivity. With the increase in the SiO2@PZS shell thickness, the electrolyte uptake, ionic conductivity and discharge capacity gradually increased. The discharge capacity of the PE-SiO2@PZS composite membrane at 8 C rate was 129 mAh/g, which was higher than the values of 107 mAh/g for the PE-SiO2 composite membrane and 104 mAh/g for the PE membrane.

A Composite Membrane with High Stability and Low Cost Specifically for Iron-Chromium Flow Battery.

The iron–chromium flow battery (ICFB), the earliest flow battery, shows promise for large-scale energy storage due to its low cost and inherent safety. However, there is no specific membrane designed that meets the special requirements of ICFBs. To match the harsh operation parameters of ICFBs, we designed and fabricated a composite membrane with high mechanical, chemical, and thermal stability. In the design, a commercial porous polyethylene membrane is selected as the framework material, offering high mechanical stability and reducing the cost. Meanwhile, the Nafion resin is filled in the pores of a porous membrane, which inhibits the transfer of redox-active ions and creates the proton channels via hydrophobic/hydrophilic phase separation. As a result, the composite membrane exhibits high conductivity, selectivity, and stability, especially with almost no swelling at high operating temperatures. Thus, an ICFB with the prepared membrane exhibits a coulombic efficiency of 93.29% at the current density of 80 mA cm−2 and runs stably for over 300 cycles. This work provides an easy method to fabricate high-performance and low-cost membranes specifically for ICFBs and has the potential to promote the development of ICFBs.

Study of Wettability of Polyethylene Membranes for Food Packaging

In this study, the wettability of PET membranes (prepared with different pore sizes) treated by UV irradiation, thermal annealing or doping with metal nanoparticles was investigated. The wettability was studied using the contact angle method based on the optical microscopy. The membranes were analyzed before and after pore etching, and after each applied treatment. It turned out that membranes with different pore sizes exhibit different wetting behavior. Of particular interest are membranes with 0.53 μm pores. When pristine, they show high hydrophobicity (a high contact angle), but after treatment (some of which can be considered as an accelerated aging), their wetting characteristics swap between a hydrophobic and hydrophilic state. Interactions between packaging material and food and the external environment through fine control of wettability could have a major impact on maintaining product quality.

Stable fouling resistance of polyethylene (PE) separator membrane via oxygen plasma plus zwitterion grafting

Low-cost and fouling resistant microfiltration/ultrafiltration membranes for wastewater treatment has been a challenging task when balancing the membrane cost and performance stability. Herein, a low-cost polyethylene (PE) lithium-ion battery separator was explored as a potential solution. To tackle the intrinsic hydrophobic character which incurs severe fouling, a novel cascade process of plasma treatment plus zwitterion grafting was designed: first oxygen plasma to endow oxygen-containing groups for hydrophilicity and supply “grafting sites”, and grafting zwitterion 3-[[3-(trimethoxysilane)-propyl] amino] propane-1-sulfonic acid (TMAPS) for robust fouling resistance. The membranes were analyzed by water contact angle, Fourier-transform Infrared Spectroscopy (FTIR), Energy Dispersive Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS). Challenged by two typical foulants, e.g., humic acid (HA) and bovine serum albumin (BSA), the zwitterion grafted membrane showed the best antifouling performance. Oxygen plasma treated PE membrane presented a better performance towards HA than to BSA. The Resistance-in-Series model revealed that the plasma-treated membrane showed improvement in reversible resistance but not in irreversible resistance. Migration of hydrophobic PE segment to the surface due to the low glass transition temperature was attributed to the low fouling resistance of the plasma-treated membrane. However, the zwitterion-grafted membrane led to stabilized hydrophilicity and inhibited the hdrophobic-hydrophobic interaction between the membrane and foulant, thus resulting to significantly improved flux recovery and low irreversible fouling rate. This study clarified that oxygen plasma alone is not sufficient to provide sufficient fouling resistance, but grafting with zwitterion provides stable hydrophilicity and fouling resistance.

Long-Term Treatment of Highly Saline Brine in a Direct Contact Membrane Distillation (DCMD) Pilot Unit Using Polyethylene Membranes.

Membrane distillation (MD) is an attractive separation process for wastewater treatment and desalination. There are continuing challenges in implementing MD technologies at a large industrial scale. This work attempts to investigate the desalination performance of a pilot-scale direct contact membrane distillation (DCMD) system using synthetic thermal brine mimicking industrial wastewater in the Gulf Cooperation Council (GCC). A commercial polyethylene membrane was used in all tests in the DCMD pilot unit. Long-term performance exhibited up to 95.6% salt rejection rates using highly saline feed (75,500 ppm) and 98% using moderate saline feed (25,200 ppm). The results include the characterization of the membrane surface evolution during the tests, the fouling determination, and the assessment of the energy consumption. The fouling effect of the polyethylene membrane was studied using Humic acid (HA) as the feed for the whole DCMD pilot unit. An optimum specific thermal energy consumption (STEC) reduction of 10% was achieved with a high flux recovery ratio of 95% after 100 h of DCMD pilot operation. At fixed operating conditions for feed inlet temperature of 70 °C, a distillate inlet temperature of 20 °C, with flowrates of 70 l/h for both streams, the correlations were as high as 0.919 between the pure water flux and water contact angle, and 0.963 between the pure water flux and salt rejection, respectively. The current pilot unit study provides better insight into existing thermal desalination plants with an emphasis on specific energy consumption (SEC). The results of this study may pave the way for the commercialization of such filtration technology at a larger scale in global communities.

Asymmetric Design for a High‐Performance Indoor Radiative Heating Fabric

AbstractImproving radiative heating performance of textiles is becoming one of the most current research topics to reduce the energy consumption used to control the indoor areas temperature. In this work, the properties of a textile‐based asymmetric design for radiative heating are studied both theoretically and experimentally, and its remarkable efficiency over a wide range of temperature is demonstrated. By sandwiching a thin metallic layer characterized by a high reflectivity in the mid‐infrared (MIR) between two polyethylene (PE) membranes of same thickness, it is proposed to control the MIR emissivity of the structure by the introduction of SiO2 nanoparticles (NPs) in one of the two PE membranes. By reversing the fabric side to side, a wide comfort zone can be achieved for medium and low ambient temperatures, typically between 7.1 and 16.3 °C. Moreover, it is shown that, when transferred on a regular textile, the fabric performs the same functionalities. The experimental demonstration is done by considering an equivalent asymmetric structure with thicker membranes, without NPs. The fabrication and characterization processes are reported and a good agreement is obtained between the Fourier transform infrared spectra and the numerical data.

Oriented shish-kebab like ultra-high molecular weight polyethylene membrane for direct contact membrane distillation

The special bioinspired structure will help membranes to improve the antifouling properties during the membrane distillation (MD) process. Here, a new MD utilized membrane with oriented shish-kebab structure was prepared by stirring the ultra-high molecular weight polyethylene (UHMWPE)/decalin solution to induce the shish-kebab crystals to grow on a polyester mesh along the flow field, and then coated with fluororesin to decrease the surface energy. The multi-stage extraction drying technology was adopted to reduce the membrane shrinkage in the dry process and make the shish-kebab membranes have high porosity (77.5%). More interesting, when the water flows along the shish direction, just like the fish gill works, the membrane has better resistance to NaCl, CaCO3 scaling, due to the nanoscale structure can intensify the interfacial nanoscale turbulent flow and hinder the crystal deposition. Specifically, the membrane has a high-water recovery of 92.5% and a low conductivity increase (from 2.76 to 8.33 μS/cm in 70 h) in the long-term MD process.

Scale-up of membrane distillation systems using bench-scale data

A procedure to design full-scale air gap membrane distillation (AGMD) processes is presented. A mathematical model was then developed for both direct contact membrane distillation (DCMD) and AGMD. The model is centered on solving local mass and energy balances using a finite difference approach. The full-scale model was calibrated by utilizing the membrane distillation coefficient (MDC) determined by DCMD bench-scale experiments, as the sole adjustable parameter. The MDC was then used to model the water production and energy efficiency of a spiral-wound AGMD full-scale element. The model yields accurate representation of full-scale AGMD elements using polytetrafluoroethylene (PTFE) and polyethylene (PE) membranes. Full-scale experimental results obtained over a wide range of feed flow rates (2 to 4.5 L/min), temperatures (40 to 80 °C), and salinities (0 to 200 g/L NaCl) confirmed that the developed procedure can be applied to model and design large-scale AGMD elements. Furthermore, the model guides the selection of specific temperature and flow conditions at a given salinity and element geometry to maximize water production and energy efficiency. This methodology is suitable for rapid evaluation of novel MD membranes performance in field AGMD applications.

Bilayer Nanoporous Polyethylene Membrane with Anisotropic Wettability for Rapid Water Transportation/Evaporation and Radiative Cooling.

Both sweat drainage and evaporation play important roles in achieving personal moisture and thermal management during sweat-producing exercises. However, it remains a great challenge to simultaneously realize thermal management through radiative cooling for human body without perspiration. Herein, we report a bilayer nanoporous polyethylene membrane with anisotropic wettability, which possesses superior radiative cooling ability (∼2.6 °C lower than that of cotton) without perspiration. Meanwhile, it realizes efficient sweat drainage and good evaporation cooling property (∼1.0 °C lower than that of cotton) in perspiration to avoid sticky and hot sensation. In addition, it can also block water and fine particulate matter owing to the hydrophobic nanoporous structure. By virtue of the outstanding personal thermal and moisture management performance, it is expected that this study provides inspiration for designing new clothing and medical protective suits with more comfortable microclimates and reducing energy consumption for global sustainability.

Effect of polyethylene powder and heating treatment on the microstructure and hardened properties of foam concrete

To tackle the energy consumption issue and meet the energy-efficiency building requirement, this study proposes a method by incorporating polyethylene (PE) powder as a multi-function and low-cost construction material in the foam concrete to enhance the thermal insulation. The effects of heating treatment and dosages of PE powder on the dry density, compressive strength, water absorption, thermal conductivity and microstructure of foam concrete were investigated. The pore structure and morphology were examined using Image-Pro-Plus software, electron microscope and SEM-EDS. Results indicate that the dry density and compressive strength of foam concrete generally decreased, while the water absorption overall increased with higher dosage of PE powder. Thermal conductivity of foam concrete containing PE powder without heating treatment exhibited a rising trend with the increase of dosage, while that of foam concrete prepared with the PE powder was greatly inhibited by heating treatment. Both the average roundness of pores and the porosity of foam concrete increased with the incorporation of PE powder, but the smaller effective pore size in the foam concrete with heating treatment was significant. The PE membrane coated on the pore wall and clogged the pore structure, which was verified by SEM-EDS analysis on the microstructure of foam concrete after heating treatment.

Engineering biaxial stretching polyethylene membrane with poly(amidoxime)-nanoparticle and mesopores architecture for uranium extraction from seawater

Conventional polymeric adsorbents encapsulate most of their ligand groups (such as amidoxime, AO) in dense structures, leading to problems such as low adsorption capacity for Uranium extraction from seawater (UES). The uranium coordination environment of polymeric adsorbents has not been positively identified even after decades of research. Therefore, a new and functional Biaxially stretched polyethylene (BSPE) membrane with Poly-amidoxime (PAO) nanoparticles, mesoporous architecture, and nano-channels (PAO-BSPE) was fabricated in this study for UES, based on the interfacial self-assembly of axial grafting chains. The underlying mechanism involved in the formation of the PAO-BSPE membrane was elucidated using first-principles computations of the various reactions. The engineered PAO-BSPE membrane exhibited excellent hydrophilicity, good mechanical properties, high specific surface area, and contained mesoporous architecture and nano-channels, which facilitated advantages in terms of kinetics, capacity, and renewability in both laboratory experiments and marine field-testing. After 64 days of adsorption in natural seawater, the PAO-BSPE membrane with a low degree of grafting of 70.5% exhibited a high uranium-adsorption-capacity of 12.67 mg-U/g-ads, which was 1.77 times higher than that toward vanadium. The PAO-BSPE membrane efficiently extracted uranium in the presence of high concentrations of co-existing ions, with the distribution coefficient reaching 4.09 × 106 mL/g in natural seawater. The total amount of uranium recovered by the PAO-BSPE membrane was 15.0 g in terms of yellow cake during a total submersion time of 30 days in the ocean. The adsorbent exhibited a long service life of at least 12 cycles. Furthermore, near-edge and extended X-ray absorption fine structure spectroscopy analyses suggested that the mechanism of uranium adsorption involved the formation of a stable complex via the linkage of uranium with two amidoximes in a cooperative chelating fashion. This study presents a new adsorbent with improved efficiency for UES, which has significant implications for the development of polymer adsorbents with high selectivity.

Influence of post-irradiation conditions on crosslinking and oxidation of microporous polyethylene membrane

Prevalence of oxidation reactions through electron-beam (EB) treatment of microporous polyethylene membranes under various atmospheres and over a range of doses was investigated to determine the appropriate conditions assisting the viability of crosslinking. EB treatment in air promoted oxidation of membranes so that no gel content was measured, however, this made them slightly less hydrophobic. Although there was a reduction in the oxidation reactions when performing the EB treatment under vacuum, but no detectable gel content was yet found which was assumed to be due to post-irradiation oxidation reactions via trapped radicals upon exposing the EB modified membranes to the air ambient. Therefore, in another experiment designated as VacuumN2, the membrane was kept under nitrogen gas immediately after EB treatment in vacuum allowing the decay of trapped radicals in an inert atmosphere. Consequently, oxidation reactions were practically eliminated leading to a measurable amount of gel content in EB modified membrane under VacuumN2. Additionally, SEM micrographs of EB modified membrane under VacuumN2 verified the enhanced thermal stability by rather preserving the original pattern of the membrane subsequent to thermal annealing close to its melting temperature. Furthermore, regarding the DSC analysis of EB modified membranes, it was overall found that crystallization exotherms are more affected than melting endotherms by the conditions during and after EB treatment.

High flux and high selectivity thin-film composite membranes based on ultrathin polyethylene porous substrates for continuous removal of anionic dyes

Thin-film composite (TFC) nanofiltration (NF) membranes efficiently remove dyes from wastewater. However, most of the membranes often sacrifice water flux for high rejection because of the trade-off between them. The demand for TFC membranes with high rejection and high water flux is increasing. Here, polyethylene (PE) membrane with a thickness of 7 µm was covered by polydopamine and polyethyleneimine (PDA/PEI), and then directly initiated interfacial polymerization (IP) with trimesoyl chloride (TMC), forming the dense and negatively charged polyamide-polyester selective layer. As the amount of PDA/PEI increases, the selective layer becomes denser, leading to the efficient removal of anionic dyes at high water flux. The water flux of the optimal membrane is 61.0 ± 18.3 L m−2 h−1 bar−1, and the removal efficiency is 91.4 ± 0.8% for an anionic dye eosin Y (EY, Mw = 691.9 Da), but poor decolorization for natural VB12 (Mw = 1355.4 Da). Moreover, the TFC membrane shows excellent selectivity for filtrating dye/NaCl mixture solution. The synergistic effect of adsorption-filtration control the removal of anionic dyes from wastewater in large flux. This work utilizes commercial PE porous substrate to fabricate TFC membrane having outstanding separation performance and a low thickness of about 7 µm.

Lithium-Ion-Conducting Ceramics-Coated Separator for Stable Operation of Lithium Metal-Based Rechargeable Batteries.

Lithium metal anode is regarded as the ultimate negative electrode material due to its high theoretical capacity and low electrochemical potential. However, the significantly high reactivity of Li metal limits the practical application of Li metal batteries. To improve the stability of the interface between Li metal and an electrolyte, a facile and scalable blade coating method was used to cover the commercial polyethylene membrane separator with an inorganic/organic composite solid electrolyte layer containing lithium-ion-conducting ceramic fillers. The coated separator suppressed the interfacial resistance between the Li metal and the electrolyte and consequently prolonged the cycling stability of deposition/dissolution processes in Li/Li symmetric cells. Furthermore, the effect of the coating layer on the discharge/charge cycling performance of lithium-oxygen batteries was investigated.

Microwave Assisted Grafting of Polyethylene Membrane Through Imidazolium and Pyridinium Moieties for Anion Exchange Membranes in Fuel Cell Applications

Microwave Assisted Grafting of Polyethylene Membrane Through Imidazolium and Pyridinium Moieties for Anion Exchange Membranes in Fuel Cell Applications

Surgical Repair of Orbital Blow-Out Fractures: Outcomes and Complications.

Objectives:The purpose of this study is to evaluate the demographics of patients with orbital blow-out fractures, as well as the success and complications of surgical repair with porous polyethylene membrane sheet implants through transconjunctival technique and to compare the results to previously published studies.Methods:This retrospective study included 57 patients diagnosed with orbital blow-out fractures referred to our clinic between 2018 and 2022. Seventeen patients (29.8%) underwent orbital fracture repair through a transconjunctival technique employing porous polyethylene membrane sheets. The indications for surgery were enophthalmos >2 mm and persistent ocular motility restriction, diplopia, and strabismus. The success criteria were <2 mm of enophthalmos and complete correction of eye motility, diplopia, and strabismus.Results:The study group consisted of ten females and 47 males with a mean age of 31.12 years. The most common cause of injury was assaults (50.9%), followed by falls (38.6%), traffic accidents (5.3%), and accidental impacts (5.3%). The inferior wall (61.4%) was the most common fracture site, followed by the medial wall (21.1%) and a combination of the inferior and medial walls (21.1%). The surgically treated group showed a significant improvement in ocular motility restriction (88.2–23.5%, p=0.002), diplopia (70.6–23.5%, p=0.008), and enophthalmos (1.41 mm to 0.82 mm, p=0.012) after surgery. The surgery was successful in ten of 17 cases (58.8%), and the success rate was higher in patients who were treated early (77.8% vs. 37.5%), but the difference was not statistically significant (p=0.092).Conclusion:Orbital blow-out fracture repair using porous polyethylene membrane sheets through a transconjunctival approach is a safe and effective surgical technique for orbital blow-out fracture repair. Although patients who had early surgery had a higher success rate in our study group, larger study groups are needed to assess the effect of surgical timing on success.

Poly(dopamine) surface‐modified polyethylene separator with electrolyte‐philic characteristics for enhancing the performance of sodium‐ion batteries

Sodium-ion batteries (NIBs) are promising candidates for next-generation rechargeable batteries with high energy density. Na ion with global abundance exhibits similar chemical characteristics to Li ion for rechargeable batteries. However, the polyethylene (PE) membrane, a conventional safety separator used for lithium-ion batteries, is inappropriate for NIBs due to its hydrophobic properties in NIBs liquid electrolytes and extremely poor ionic conductivity. Therefore, modifications to the PE separator are required to induce better electrochemical performance NIBs. Herein, we introduce a poly(dopamine)-modified PE separator by a simple dip-coating method, whereby the incorporation of the dopamine layer renders the membrane more hydrophilic in the liquid electrolyte of the NIBs. The PDA-PE separator exhibits high ionic conductivity and a long cycle life, and is stable with different current rates for Na||Na symmetric cells. Also, Na half-cell systems, consisting of hard carbon and Na metal electrodes, demonstrate considerably improved cyclability and high reversible discharge/charge with cells using PDA-treated PE separators.

Magnetoactive acoustic metamaterials based on nanoparticle-enhanced diaphragm

Magnetoactive membrane-type acoustic metamaterials are fabricated by coating a layer of magnetic nanoparticles on the polyethylene (PE) membranes and their vibration characters are investigated experimentally. From our experiments, we discovered that, under different magnetic fields by varying the distance between a magnet and the membranes, such membranes exhibit tunable vibration eigenfrequencies (the shift towards lower frequencies), which is caused by the variation of the effective mass density and effective tension coefficient resulted from the second derivative of the magnetic field. The strong magnetic force between the layer of magnetic nanoparticles and the magnet enhances the eigenfrequency shift. A spring oscillator model is proposed and it agrees well with the experimental results. We also experimentally observed that the vibration radius, effective mass density, and effective tension coefficient of the membranes can enormously affect the eigenfrequencies of the membranes. We believe that this type of metamaterials may open up some potential applications for acoustic devices with turntable vibration properties.

Cellulose-Based Films with Ultraviolet Shielding Performance Prepared Directly from Waste Corrugated Pulp.

As the most important paper packaging materials, corrugated cartons with a tremendous amount of production demonstrate several advantages and have been widely used in daily life. However, waste corrugated cartons (WCCs) are usually recycled and reused to produce new corrugated cartons, and their properties are decreased dramatically after several cycles. Therefore, recycling and converting WCCs into cellulose-based film with high value is attractive and significant. Herein, without any pretreatment, the waste old corrugated cartons were directly dissolved in ionic liquid 1-allyl-3-methylimidazolium chloride, and semitransparent cellulose-based films were successfully fabricated. It was indicated that cellulose-based films displayed better UV-shielding property and hydrophobicity than traditional cellulose films. Interestingly, the cellulose-based films regenerated from deionized water displayed higher tensile strength, elongation at break, and toughness. Their tensile strength could reach 23.16 MPa, exhibiting enormous superiority as wrapping and packaging materials to replace the petrochemical polyethylene membrane (8.95 MPa). Consequently, these renewable, biodegradable, and high-valued cellulose-based films were successfully fabricated to simultaneously realize the valorization of old corrugated cartons and supplement the petrochemical plastics.

Approaches for reduction of the temperature bias on radon detectors packed in anti-thoron polymer membranes

Passive and active detectors used for radon (222Rn) measurements can be influenced by thoron (220Rn). Polyethylene membranes are very appropriate diffusion barriers for anti-thoron protection of such detectors. However, if not properly chosen, these membranes may not reduce efficiently the thoron influence or could introduce temperature bias in the radon sensitivity of the detectors. In this work three approaches are proposed dealing with the thoron influence and the temperature bias introduced by packing in polymer membranes. The approaches exploit a model of the radon and thoron diffusion transport through the membranes and the already known diffusion properties of the membranes to estimate the thoron influence and the temperature bias and to take them into account. The approaches are experimentally verified. It is shown that, in some cases, with the proper choice of membrane the thoron influence could be reduced down to few percents introducing only a few percents temperature bias. Additionally, in the cases when temperature bias is significant and cannot be avoided (the thoron bias in that cases is shown to be below 1%), the proposed approaches allow to estimate and to correct that bias.