Excellent Barrier Properties Research Articles

Upscaled production of an ultramicroporous anion-exchange membrane enables long-term operation in electrochemical energy devices

The lack of high-performance and substantial supply of anion-exchange membranes is a major obstacle to future deployment of relevant electrochemical energy devices. Here, we select two isomers (m-terphenyl and p-terphenyl) and balance their ratio to prepare anion-exchange membranes with well-connected and uniformly-distributed ultramicropores based on robust chemical structures. The anion-exchange membranes display high ion-conducting, excellent barrier properties, and stability exceeding 8000 h at 80 °C in alkali. The assembled anion-exchange membranes present a desirable combination of performance and durability in several electrochemical energy storage devices: neutral aqueous organic redox flow batteries (energy efficiency of 77.2% at 100 mA cm−2, with negligible permeation of redox-active molecules over 1100 h), water electrolysis (current density of 5.4 A cm−2 at 1.8 V, 90 °C, with durability over 3000 h), and fuel cells (power density of 1.61 W cm−2 under a catalyst loading of 0.2 mg cm−2, with open-circuit voltage durability test over 1000 h). As a demonstration of upscaled production, the anion-exchange membranes achieve roll-to-roll manufacturing with a width greater than 1000 mm.

Development of Biodegradable Polyamide 4/Polyvinyl Alcohol/Poly(lactic acid) Multilayer Films with Tunable Water Barrier Property and Superior Oxygen Barrier Property

Poor mechanical and barrier properties of biopolymer-based packaging materials limit their widespread applications. The combination of biopolymers with different nature is considered an effective strategy to obtain complementary properties, but this method is always restricted by the incompatibility between matrices. To combine polyamide 4 (PA4) and poly(lactic acid) (PLA), which present excellent oxygen barrier and water barrier properties, respectively, this study puts forward the use of polyvinyl alcohol (PVA) as a bonding layer to connect them and form the PA4/PVA/PLA multilayer films by the layer-by-layer solution casting method. PA4 and PLA are successfully linked through hydrogen bonding and electrostatic interactions with PVA. The cross-section morphology and peel test results proved the good interlayer adhesion between layers. After combination with PA4, the tensile strength, elongation at break, and oxygen barrier properties of PLA were greatly improved. The oxygen barrier of the PA4/PVA/PLA multilayer film was more than 260 times higher than that of the PLA monolayer. PA4/PVA/PLA films presented better thermal stability, transparency, and water barrier properties compared to the PA4 monolayer. Besides, PA4/PVA/PLA multilayer films presented a one-way water barrier characteristic, which made them effective in avoiding the condensation phenomenon when used as fruit or vegetable packaging. The study improved the poor interfacial compatibility between PA4 and PLA and provided a simple strategy for developing sustainable packaging with excellent performance.

Sulfonated Polyaniline-Grafted Two-Dimensional Ti3C2-MXene (SPANI-MXene) Nanoplatform for Designing an Advanced Smart Self-Healable Coating System

MXene nanosheets (MXenes), a brand-new classification of two-dimensional (2D) nanomaterials, are assumed to be highly functional components in anticorrosion polymeric systems. In general, MXenes possess many advantageous features that can be utilized to improve the polymeric matrices' anticorrosion performance. In this work, zinc ions (Zn) were deposited on the sulfonated polyaniline (SPANI) that was polymerized on Ti3C2-MXene surfaces (MXP-Zn) in order to achieve a high-performance anticorrosion nanofiller for epoxy coating (EP-MXP-Zn). Field-emission scanning electron microscopy-transmission electron microscopy images, Fourier transform infrared, Raman, X-ray diffraction, UV-vis, derivative thermogravimetry, and thermogravimetric analysis have evidenced the successful characterization of the MXP-Zn nanocomposite. Likewise, the excellent barrier properties of SPANI, in conjunction with the cathodic protection of Zn, resulted in a novel nanocomposite that could mitigate the negative consequences of destructive ions' attack on the metal surface in an aggressive media. Quantitative and qualitative anticorrosion measurements verified the outstanding anticorrosion performance of EP-MXP-Zn over time in severe conditions. According to the electrochemical impedance spectroscopy assessments, the |Z0.01 Hz| value for EP-MXP-Zn was 1010.04 Ω cm2, which was over 105 times greater than that of neat EP (104.66 Ω cm2) over a 6-week period of immersion in a 3.5 wt % NaCl solution.

Dynamic covalent bond enabled strong Bio-based polyimide materials with Thermally-driven Adaptivity, healability and recycling

Developing new sustainable materials as plastic replacement has become an urgent task for the rapid accumulation of non-degradable petroleum-based waste plastics. Herein, we report that catalyst-free dynamic reversible exchange operated at room-temperature by Schiff base reaction between dialdehyde cellulose nanofibrils (DACNF) and plant oil-based aliphatic long-chain diamine monomers (LCD). The dynamic imine polymer films are formed using a simple method similar to wet pressing in papermaking, which exhibits excellent mechanical properties and thermally processability for the synergistic of hydrogen bond and dynamic imine bond. The tensile strength and Young's modulus reaches 83.74 MPa and 3.90 GPa, which are significantly higher than those of most traditionally commercial plastics. In addition, the number of hydrogen bonds and dynamic imine bonds from cellulose and dynamic imine polymers are evaluated by molecular dynamics (MD) simulation to gain further insights into the intermolecular interaction. By exploring the mechanism involved in the reversible exchange of dynamic imine bonds and its application in self-healing and recycling, a sustainable adaptive material is expected to be structured. More importantly, the dynamic imine polymers also exhibits excellent water barrier properties, solvent resistance and complete biodegradability, which offers a new strategy for reducing the application of non-degradable plastics.

Waste paper as a viable sustainable source for cellulosic extraction by chlorine free bleaching and acid hydrolysis method for the production of PVA-starch/cellulose based biocomposites

Cellulose nanofibers have displayed great promise for enhancing the mechanical and physical characteristics of polymer composites. Viable sustainable source such as office waste papers were used for the extraction of cellulose The cellulose was isolated using an alkali treatment followed by chlorine free bleaching, and acid hydrolysis method. This is followed by homogenization. The obtained cellulose nanocrystals (CNC) were carefully studied for its structure, morphology, and thermal properties. Polyvinyl alcohol (PVA)/starch composite films were prepared with isolated CNC (1, 3 and 5 wt%) by solution casting method. CNC added to polymer composites increased the film's mechanical strength and barrier characteristics. Films were characterised by), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The film exhibited excellent barrier properties and mechanical properties which is desirable for food packaging applications. Successful isolation of CNCs derived from waste paper enhanced the use of waste paper's fibre resources, resulting in increased economic advantages.

A Contribution to Improve Barrier Properties and Reduce Swelling Ratio of κ-Carrageenan Film from the Incorporation of Guar Gum or Locust Bean Gum.

In this study, galactomannan (GM), including guar gum (GG) or locust bean gum (LG), was incorporated into a κ-carrageenan film to improve barrier properties and reduce the swelling ratio (SR). The effects of that with different concentrations on optical, mechanical, barrier, swelling and thermal properties of the κ-carrageenan-based film were researched. SEM and rheological results showed that both κ-carrageenan/GG and κ-carrageenan/LG had good compatibility and stability. FTIR results showed that LG was easier to form hydrogen bonds with κ-carrageenan. The KC-L exhibited excellent mechanical properties, barrier properties, and SR than KC-G. The film with 15% GM had good light transmittance. Moreover, the thermal stability of the film could be improved by adding GMs. This study reports that the κ-carrageenan-GM film has potential in packaging applications.

Dialdehyde Cellulose Solution as Reducing Agent: Preparation of Uniform Silver Nanoparticles and In Situ Synthesis of Antibacterial Composite Films with High Barrier Properties

The demand for antimicrobial materials is gradually increasing due to the threat of infections and diseases caused by microorganisms. Silver nanoparticles (AgNPs) are widely used because of their broad-spectrum antimicrobial properties, but their synthesis methods are often environmentally harmful and AgNPs difficult to isolate, which limits their application in several fields. In this study, an aqueous solution of dialdehyde cellulose (DAC) was prepared and used as a reducing agent to synthesize AgNPs in an efficient and environmentally friendly process. The synthesized AgNPs can be easily separated from the reducing agent to expand their applications. In addition, the AgNPs were immobilized in situ on dialdehyde cellulose to form antibacterial composite films. The results showed that the prepared silver nanoparticles were mainly spherical and uniformly dispersed, with an average size of about 25 nm under optimal conditions. Moreover, the dialdehyde cellulose-nanosilver (DAC@Ag) composite films had excellent mechanical properties, positive transparency, ultraviolet-blocking properties, and effective antibacterial activity against E. coli and S. aureus. Notably, the composite films exhibited excellent oxygen and water vapor barrier properties, with WVT and ORT of 136.41 g/m2·24 h (30 °C, 75% RH) and <0.02 cm3/m2·24 h·0.1 MPa (30 °C, 75% RH), respectively, better than commercial PE films. Hence, this study not only provides an environmentally friendly method for the preparation of silver nanoparticles, but also offers a simple and novel strategy for the in situ synthesis of silver-loaded antibacterial composite films.

Biodegradable Nanofibrillated Cellulose/Poly-(butylene adipate-co-terephthalate) Composite Film with Enhanced Barrier Properties for Food Packaging.

Biodegradable composites consisting of Poly-(butylene adipate-co-terephthalate) (PBAT), thermoplastic starch, hydrophobically modified nanofibrillated cellulose (HMNC), and green surfactant (sucrose fatty acid ester) were prepared via the melt-mixing and film-blowing process (PBAT-HMNC). The composites were characterized using the Fourier transform infrared spectroscope (FT-IR), scanning electron microscope (SEM), and thermogravimetric analyzer (TGA). The mechanical and barrier properties were systematically studied. The results indicated that PBAT-HMNC composites exhibited excellent mechanical and barrier properties. The tensile strength reached the maximum value (over 13 MPa) when the HMNC content was 0.6% and the thermal decomposition temperature decreased by 1 to 2 °C. The lowest values of the water vapor transmission rate (WVTR) and the oxygen transmission rate (OTR) were obtained from the composite with 0.6 wt% HMNC, prepared via the film-bowing process with the values of 389 g/(m2·day) and 782 cc/(m2·day), which decreased by 51.3% and 42.1%, respectively. The Agaricus mushrooms still had a commodity value after 11 days of preservation using the film with 0.6 wt% HMNC. PBAT-HMNC composites have been proven to be promising nanocomposite materials for packaging.

Surface Engineering of Regenerated Cellulose Nanocomposite Films with High Strength, Ultraviolet Resistance, and a Hydrophobic Surface

Regenerated cellulose packaging materials can alleviate the environmental pollution and carbon emissions caused by conventional plastics and other chemicals. They require regenerated cellulose films with good barrier properties, such as strong water resistance. Herein, using an environmentally friendly solvent at room temperature, a straightforward procedure for synthesizing these regenerated cellulose (RC) films, with excellent barrier properties and doping with nano-SiO2, is presented. After the surface silanization modification, the obtained nanocomposite films exhibited a hydrophobic surface (HRC), in which the nano-SiO2 provided a high mechanical strength, whereas octadecyltrichlorosilane (OTS) provided hydrophobic long-chain alkanes. The contents of the nano-SiO2 and the concentrations of the OTS/n-hexane in regenerated cellulose composite films are crucial, as they define its morphological structure, tensile strength, UV-shielding ability, and the other performance of these composite films. When the nano-SiO2 content was 6%, the tensile stress of the composite film (RC6) increased by 41.2%, the maximum tensile stress was 77.22 MPa, and the strain-at-break was 14%. Meanwhile, the HRC films had more superior multifunctional integrations of tensile strength (73.91 MPa), hydrophobicity (HRC WCA = 143.8°), UV resistance (>95%), and oxygen barrier properties (5.41 × 10-11 mL·cm/m2·s·Pa) than the previously reported regenerated cellulose films in packaging materials. Moreover, the modified regenerated cellulose films could biodegrade entirely in soil. These results provide an experimental basis for preparing regenerated-cellulose-based nanocomposite films that exhibit a high performance in packaging applications.

Preparation and characterization of functionalized chitosan/polyvinyl alcohol composite films incorporated with cinnamon essential oil as an active packaging material

In this study, amphiphilic chitosan (NPCS-CA) was synthesized by grafting quaternary phosphonium salt and cholic acid onto the chain of chitosan, aiming to develop an active edible film based on NPCS-CA and polyvinyl alcohol (PVA) incorporated with cinnamon essential oil (CEO) by the casting method. The chemical structure of the chitosan derivative was characterized by FT-IR, 1H NMR and XRD. Through the characterization of FT-IR, TGA, mechanical and barrier properties of the composite films, the optimal proportion of NPCS-CA/PVA was determined as 5/5. And, the tensile strength and elongation at break of the NPCS-CA/PVA (5/5) film with 0.4 % CEO were 20.32 MPa and 65.73 %, respectively. The results revealed that the NPCS-CA/PVA-CEO composite films exhibited an excellent ultraviolet barrier property at 200–300 nm and significantly reduced oxygen permeability, carbon dioxide permeability and water vapor permeability. Furthermore, the antibacterial property of film-forming solutions against E. coli, S. aureus, and C. lagenarium was distinctly improved with the increase of NPCS-CA/PVA proportion. And, the multifunctional films effectively extended the shelf-life of mangoes at 25 °C based on the characterization of surface changes and quality indexes. The NPCS-CA/PVA-CEO films could be developed as biocomposite food packaging material.

A Comparative Study on the Development of Bioactive Films Based on β-glucan from Spent Brewer’s Yeast and Pomegranate, Bilberry, or Cranberry Juices

This study provides new insight into developed bioactive films. The development of film-forming solutions from different fruit juices has demonstrated a major impact of bioactive compounds in film formulation, from smart packaging to bioactive packaging that releases the compounds from the oral solution at the same time as the packaged product. There were significant influences among independent parameters such as yeast β-glucan, gelling agent, fruit juice, or surfactant for each individual film. However, in this study, it was found that the amount of juice was the most significant factor in assigning their properties to all three types of films made of different juices (pomegranate, bilberry, and cranberry). Properties such as WVTR through the film varied within quite wide limits between 3.2562 and 32.1869 g/h·m2, while their solubilization time started from a few seconds for a complete dissolution or ensured only partial dissolution after 10 min of stirring (in the case of films made of β-glucan and cranberry juice). Therefore, natural biopolymer-based films developed with excellent water vapor barrier properties and improved solubility have a huge potential for application as packaging materials for dry powdered such as pharmaceuticals.

Impact of Zinc Oxide Nano Particles, Poly Vinyl Alcohol, and Natural Polymers on Quality Characteristics of Nanocomposite Film

The use of biodegradable films to replace the synthetic polymers prepared from natural polymers has been strongly limited owing to their poor barrier and mechanical properties. The modification was carried out with a partial replacement of natural polymers with synthetic polymer, such as PVA (poly vinyl alcohol), to increase the barrier properties of the film. The addition of an active ingredient in the form of nanoparticles such as Zinc Oxide (ZnO), enhanced the properties of the packaging materials compared to the conventional composite film, to which sonication imparted an excellent dispersion of nanoparticles in the slurry. The film thickness, water vapor permeability, film solubility, and mechanical properties of the composite, the composite with PVA, and the composite with PVA and ZnO nanoparticle film (active film) values differed significantly (p &lt; 0.05) between the samples. The Z-average diameters of the composite slurry, the composite with PVA slurry, and the composite with PVA and ZnO nanoparticle slurry ranged from 242.20 to 1021.03 in nanometers (d-nm). The PDI and zeta potential of the samples were also analyzed. The antibacterial activity of the nanoparticles showed a distinct inhibition against Gram-positive Bacillus cereus and Gram-negative Escherichia coli in the treated films counterpart to the control films. The active film conferred excellent mechanical and barrier properties, including antibacterial properties.

Supercritical CO2 permeation in polymeric films: Design, characterization, and modeling

This study is concerned with the development of an optimum method for identification of supercritical CO2 permeability in thermoplastic films with moderate to excellent barrier properties namely, High-Density Polyethylene (HDPE), Raised-Temperature Polyethylene (PE-RT), Polyvinylidene Fluoride (PVDF) and aliphatic Polyketone (PK) at elevated temperatures (40 °C−82 °C). A high-temperature/high-pressure permeation cell was designed based on the “closed-volume/variable pressure” standard test method. The identified gas transport properties using the time lag method yielded significant error particularly for PVDF and PK, which was ascribed to the sole reliance on the accumulated pressure-rate in steady-state. This error was minimized using the Non-Linear Regression (NLR) by utilizing the full range of measured data including the transient state. The coefficient of determination between the measured and modeled data using NLR was quantified above 0.99 for all the polymers at the entire examined temperature range. The 1.4 % higher degree of crystallinity and 28.5 % smaller spherulite size caused 13.3 % higher diffusivity and 8.6 % lower solubility in PE-RT when compared with HDPE at 82°C. As a result of this trade-off, PE-RT exhibited only 3.5 % higher permeability than HDPE. The developed generalized temperature-dependent model provided the essential data for design optimization of gas barrier performance in multilayer high-temperature pressure-vessels.

Preparation and characterization of Aloe vera polysaccharide-based packaging film and its application in blueberry preservation

In this study, AVP-HMBCa-CNCs films were prepared based on Aloe vera polysaccharide (AVP), using β-hydroxy-β-methylbutyrate calcium (HMBCa) and nanocellulose (CNCs) as cross-linking and reinforcing agents, respectively, whose effect on freshness preservation of blueberry was investigated. The films were prepared by casting and solvent volatilization. The effects of HMBCa concentration on the physicochemical properties and bioactivity of the films were explored with SEM, FTIR, XRD and TG, showing that HMBCa addition concentrations of 0.1 to 0.5 mg mL−1 exhibited excellent mechanical and barrier properties. In the meantime, adding HMBCa not only improves transparency and reduces solubility, but also boosts the film's antioxidant and antibacterial ability. In addition, AVP-0.25HMBCa-CNCs film showed excellent performance in terms of hardness, respiration rate, weight loss, relative conductivity, total soluble solids and titrable acidity of blueberry. Besides, thermal metrology provides valuable information for edible film storage technology. Therefore, as a transparent edible film, AVP-HMBCa-CNCs film has great potential for green and food preservation.

A green nanocomposite membrane for concrete moisturizing, with excellent barrier properties and aging resistance

In order to solve the problems of moisture retention and environmental pollution in external curing of concrete, a polylactic acid (PLA)/titanium dioxide (TiO2) composite concrete curing membrane with ultraviolet aging resistance and hydrolytic degradation was prepared by melt blending method. It was found that TiO2 nanoparticles as nucleating agent significantly improved the water vapor barrier properties of PLA by regulating the crystallinity and prolonging the tortuous path. Compared with pure PLA, the barrier properties of the composite membrane added with TiO2 is improved by 34.3%. In addition, the degradation weight loss percent of the composite membrane reaches 69.9% due to the hydrophilic hydroxyl groups on the surface of TiO2 nanoparticles. The PLA/TiO2 composite membrane still maintains excellent mechanical properties and barrier properties after UV aging due to the UV shielding effect of TiO2.

Engineering chitosan into fully bio-sourced, water-soluble and enhanced antibacterial poly(aprotic/protic ionic liquid)s packaging membrane

The design and facile preparation of water-soluble and eco-friendly polymer packaging membrane materials is a fascinating research topic, particularly in terms of the increasing concerns on potential microplastics pollution in ecosystem. In this study, taking advantages of the structural features of chitosan (CS) and betaine hydrochloride (BHC), fully bio-sourced and water-soluble poly(aprotic/protic ionic liquid)s (PAPILs) were successfully designed and prepared through the reaction of the amino groups in CS and carboxyl groups in BHC. The structure and thermo-properties of the PAPILs were elucidated by a series of characteristic methods. The rheological properties of the PAPILs aqueous solutions were also investigated. Moreover, water-soluble PAPILs membrane with a smooth surface morphology and a tensile strength of 62.9 MPa was successfully prepared. The PAPILs membrane also exhibited satisfactory biocompatibility, excellent antibacterial activities and high oxygen barrier property. Together with these outstanding material performance and functionality, as a “proof of concept”, the potential use of the PAPILs membrane as water-soluble packaging material for laundry detergent capsule and pesticide was preliminarily demonstrated. These findings provide significant insights for the design of sustainable and functional packaging materials by using natural resources.

Efficient preparation of hydrogen barrier films by ultrasonic‐assisted layer‐by‐layer assembly

AbstractGraphene oxide (GO) can be self‐assembled with various polymer materials layer by layer to prepare composite materials with excellent barrier properties. However, the process is cumbersome and time‐consuming. In this article, GO/polyethyleneimine(PEI) hydrogen barrier films were successfully prepared by ultrasonic‐assisted layer‐by‐layer self‐assembly technology. Results show that the ultrasonic‐assisted method not only reduced the immersion time from several minutes to 10 s, but also increased the density of the material packing to reduce the channels through which hydrogen molecules can diffuse while improving the horizontal orientation of the GO sheet to prolong the diffusion paths of gas molecules. Finally, the hydrogen transmission rate of 20‐bilayer films assembled under ultrasonic conditions is equivalent to that of 30‐bilayer films assembled without ultrasonic conditions, which greatly shortens the film‐making period. Therefore, the ultrasonic‐assisted method has a good prospect in the preparation of gas barrier films.

Electron transport, ferroelectric, piezoelectric and optical properties of two-dimensional In2Te3: a first-principles study.

Two-dimensional (2D) materials have garnered significant interest in the fields of optoelectronics and electronics due to their unique and diverse properties. In this work, the electron transport, ferroelectric, piezoelectric, and optical properties of 2D In2Te3 were systematically investigated using first-principles based on density functional theory. The analysis of the phonon spectrum and elastic modulus of the Born effective criterion indicates that the structure of the novel 2D In2Te3 is dynamically stable. The calculation results show that 2D In2Te3 exhibits a carrier mobility as high as 3680.99 cm2 V-1 s-1 (y direction), a high in-plane polarization of 2.428 × 10-10 C m-1, and an excellent ferroelectric phase transition barrier (52.847 meV) and piezoelectric properties (e11 = 1.52 × 10-10 C m-1). The higher carrier mobility is attributed to the band degeneracy and small carrier effective mass. In addition, biaxial strain is an effective way to modulate the band gap and optical properties of 2D In2Te3. These properties indicate that 2D In2Te3 is a promising candidate material for flexible electronic devices and ferroelectric photovoltaic devices.

Bio-based food packaging materials: A sustainable and Holistic approach for cleaner environment- a review

The contribution of plastic packaging in food is substantial, but issues associated with its biodegradability and recycling initiates major concerns for environment and human health thus necessitating substitution of conventional synthetic plastics with bio-based packaging materials. Studies have demonstrated economic competition of bio-based materials with synthetic plastics because of their biodegradability, wide availability, excellent barrier and mechanical properties. These materials can be commercialized on a large scale but still somehow are under-investigated in many areas. Moreover, some of the influencing factors including confusion between bio-based and biodegradability pose a significant challenge on evolution of bio-based packaging. Therefore, the review focuses on bio-based packaging materials derived from various renewable resources like biomass, microorganisms and microalgae involving their possible food packaging applications along with required development in multiple regions for proper utilization of offered advantages in the food packaging market.

Cellulose-based natural nanofibers for fresh produce packaging: current status, sustainability and future outlook

Cellulose-based natural nanofibers in fresh produce packaging can provide benefits, including excellent barrier and carrier properties due to high surface area-to-volume ratio, which can help prevent spoilage and extend shelf life.