Corrigendum: Random cellulose acetate nanofibers: a breakthrough for cultivated meat production

[This corrects the article DOI: 10.3389/fnut.2023.1297926.].

Electrospun Materials Based on Cellulose Acetate Loaded with Rosmarinic Acid with Antioxidant and Antifungal Properties

Fibrous cellulose acetate (CA) materials loaded with rosmarinic acid (RA) were successfully created by one-pot electrospinning. In order to improve the water solubility of the polyphenolic acid and to facilitate its release from the fibrous materials, the non-ionic water-soluble polyethylene glycol (PEG) was added. Detailed characterization of the fabricated fibrous CA/RA and CA/PEG/RA materials was performed using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), UV-Vis spectroscopy and water contact angle analysis. The optimal ratio between CA, RA and PEG for preparation of defect-free and uniform fibers was accomplished by varying their concentrations. Furthermore, the incorporation of the PEG improved the hydrophilicity and wettability of the fibrous CA materials. Moreover, PEG facilitated the RA release and over 360 min, the amount released from fibrous CA/PEG/RA fibers was 91%, while that released from CA/RA materials was 53%. Both of the RA-containing fibrous materials, with and without PEG, manifested high antioxidant activity as determined by the DPPH free radical-scavenging method. In addition, the electrospun CA/PEG/RA materials displayed good antifungal activity against C. albicans. These features make the fibrous CA/PEG/RA materials promising candidates for treatment of wound infections.

Self-healing and shape-memory polymers based on cellulose acetate matrix

The creation of self-healing polymers with superior strength and stretchability from biodegradable materials is attracting increasing attention. In this study, we synthesized new biomass-derived cellulose acetate (CA) derivatives by ring-opening graft polymerization of δ-valerolactone followed by the introduction of ureidopyrimidinone (Upy) groups in the polymer side chains. Due to the semicrystalline aliphatic characteristics of the side chain poly(δ-valerolactone) (PVL) and quadruple hydrogen bonds formed by the Upy groups, the stretchability of the resulting polymers was significantly enhanced. Moreover, the shape memory ability and self-healing property (58.3% of self-healing efficiency) were successfully imparted to the polymer. This study demonstrates the great significance of using biomass sources to create self-healing polymers.

Photopolymerization Pattern of New Methacrylate Cellulose Acetate Derivatives

Polymeric photocrosslinked networks, of particular interest in the design of materials with targeted characteristics, can be easily prepared by grafting light-sensitive moieties, such as methacrylates, on polymeric chains and, after photochemical reactions, provide materials with multiple applications via photopolymerization. In this work, photopolymerizable urethane-methacrylate sequences were attached to free hydroxyl units of cellulose acetate chains in various proportions (functionalization degree from 5 to 100%) to study the properties of the resulting macromolecules and the influence of the cellulosic material structure on the double bond conversion degree. Additionally, to manipulate the properties of the photocured systems, the methacrylate-functionalized cellulose acetate derivatives were mixed with low molecular weight dimethacrylate derivatives (containing castor oil and polypropylene glycol flexible chains), and the influence of UV-curable composition on the photopolymerization parameters being studied. The achieved data reveal that the addition of dimethacrylate comonomers augmented the polymerization rates and conversion degrees, leading to polymer networks with various microstructures.

Cellulose Acetate-Ionic Liquid Blends as Potential Polymers for Efficient CO2 Separation Membranes

CO2 capture, applied in CO2 separation from natural gas or in CO2/N2 separation from power plant flue gas streams, is of great importance for technical, economic, and environmental reasons. The latter seems important because CO2, as a greenhouse gas, is considered the main contributor to global warming. Using polymeric membranes for CO2 separation presents several advantages, such as low energy demand, small equipment volume, and the absence of liquid waste. In this study, two ionic liquids (ILs) were used for the preparation of cellulose acetate (CA)-IL blend membranes for potential CO2 capture applications, namely, 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim+][HSO4-]) and choline glycine ([Ch+]Gly-), as they present adequate CO2 dissolution ability. The first IL is commercially available, whereas the latter was synthesized by a novel route. Several composite membranes were prepared through the solvent casting technique and characterized by a variety of methods, including thermogravimetry, calorimetry, FTIR spectroscopy, and X-ray diffraction. The CO2 sorption in the composite membranes was experimentally measured using the mass loss analysis (MLA) technique. The results showed that the ILs strongly interacted with the C=O groups of CA, which exhibited high affinity with CO2. In the case of [Bmim+][HSO4-], a reduction in the available sites that allow strong intermolecular interactions with CO2 resulted in a decrease in CO2 sorption compared to that of pure CA. In the case of [Ch+]Gly-, the reduction was balanced out by the presence of specific groups in the IL, which presented high affinity with CO2. Thus, the CA-[Ch+]Gly- blend membranes exhibited increased CO2 sorption capability, in addition to other advantages such as non-toxicity and low cost.

Water-Based Generators with Cellulose Acetate: Uncovering the Mechanisms of Power Generation

Power generation technologies based on water movement and evaporation use water, which covers more than 70% of the Earth's surface and can also generate power from moisture in the air. Studies are conducted to diversify materials to increase power generation performance and validate energy generation mechanisms. In this study, a water-based generator was fabricated by coating cellulose acetate with carbon black. To optimize the generator, Fourier-transform infrared spectroscopy, specific surface area, zeta potential, particle size, and electrical performance analyses were conducted. The developed generator is a cylindrical generator with a diameter of 7.5 mm and length of 20 mm, which can generate a voltage of 0.15 V and current of 82 μA. Additionally, we analyzed the power generation performance using three factors (physical properties, cation effect, and evaporation environment) and proposed an energy generation mechanism. Furthermore, we developed an eco-friendly and low-cost generator using natural fibers with a simple manufacturing process. The proposed generator can contribute to the identification of energy generation mechanisms and is expected to be used as an alternative energy source in the future.

"Nano in Nano"-Incorporation of ZnO Nanoparticles into Cellulose Acetate-Poly(Ethylene Oxide) Composite Nanofibers Using Solution Blow Spinning

In this work, the preparation and characterization of composites from cellulose acetate (CA)-poly(ethylene oxide) (PEO) nanofibers (NFs) with incorporated zinc oxide nanoparticles (ZnO-NPs) using solution blow spinning (SBS) is reported. CA-PEO nanofibers were produced by spinning solution that contained a higher CA-to-PEO ratio and lower (equal) CA-to-PEO ratio. Nanoparticles were added to comprise 2.5% and 5% of the solution, calculated on the weight of the polymers. To have better control of the SBS processing conditions, characterization of the spinning suspensions is carried out, which reveals a decrease in viscosity (two- to eightfold) upon the addition of NPs. It is observed that this variation of viscosity does not significantly affect the mean diameters of nanofibers, but does affect the mode of the nanofibers' size distribution, whereby lower viscosity provides thinner fibers. FESEM-EDS confirms ZnO NP encapsulation into nanofibers, specifically into the CA component based on UV-vis studies, since the release of ZnO is not detected for up to 5 days in deionized water, despite the significant swelling of the material and accompanied dissolution of water-soluble PEO. Upon the dissolution of CA nanofibers into acetone, immediate release of ZnO is detected, both visually and by spectrometer. ATR-FTIR studies reveal interaction of ZnO with the CA component of composite nanofibers. As ZnO nanoparticles are known for their bioactivity, it can be concluded that these CA-PEO-ZnO composites are good candidates to be used in filtration membranes, with no loss of incorporated ZnO NPs or their release into an environment.

Preparation of cellulose acetate based flexible separator and its application in zinc-air batteries

Flexible solid-state zinc-air batteries as a wearable energy storage device with great potential, and their separators, which control ion permeability, inhibit zinc dendrite generation, and regulate catalytic active sites, have been developed as gel electrolyte separators with high retention of electrolyte uptake. However, the gel electrolyte separator still has problems such as poor affinity with the electrolyte and poor ionic conductivity, which limits its further application. In order to further improve the electrolyte absorption, ionic conductivity and mechanical strength of cellulose acetate(CA)/polyvinyl alcohol (PVA) nanofibers, TiO2was added to CA/PVA to increase the porosity, and glutaraldehyde (GA) was used to modify the CA/PVA/TiO2separator by acetal reaction with CA and PVA to make the molecules closely linked. The results shows that the optimal mass fractions of TiO2and GA were 2% and 5%, respectively. At this time, the porosity and absorption rate of the separator increased from 48% to 68.2% and 142.4% to 285.3%, respectively. The discharge capacity reached 179 mA cm-3, and the cycle stability rate was 89% after 7 stable constant current charge/discharge cycles.

Random cellulose acetate nanofibers: a breakthrough for cultivated meat production

Overcoming the challenge of creating thick, tissue-resembling muscle constructs is paramount in the field of cultivated meat production. This study investigates the remarkable potential of random cellulose acetate nanofibers (CAN) as a transformative scaffold for muscle tissue engineering (MTE), specifically in the context of cultivated meat applications. Through a comparative analysis between random and aligned CAN, utilizing C2C12 and H9c2 myoblasts, we unveil the unparalleled capabilities of random CAN in facilitating muscle differentiation, independent of differentiation media, by exploiting the YAP/TAZ-related mechanotransduction pathway. In addition, we have successfully developed a novel process for stacking cell-loaded CAN sheets, enabling the production of a three-dimensional meat product. C2C12 and H9c2 loaded CAN sheets were stacked (up to four layers) to form a ~300-400 μm thick tissue 2 cm in length, organized in a mesh of uniaxial aligned cells. To further demonstrate the effectiveness of this methodology for cultivated meat purposes, we have generated thick and viable constructs using chicken muscle satellite cells (cSCs) and random CAN. This groundbreaking discovery offers a cost-effective and biomimetic solution for cultivating and differentiating muscle cells, forging a crucial link between tissue engineering and the pursuit of sustainable and affordable cultivated meat production.

Degradation Characteristics of Cellulose Acetate in Different Aqueous Conditions

Cellulose acetate (CA) is widely used in cigarette filters and packaging films, but due to its acetylation, it is difficult to degrade in the natural environment, and the problem of pollution has become a serious challenge. Understanding the degradation behavior and performance of CA in different environments is the basis and prerequisite for achieving its comprehensive utilization and developing efficient degradation methods. In this study, we investigated the degradation performance of CA in different aqueous environments to evaluate the effects of pH, salinity and microorganisms on CA degradation. The CA tows and films were immersed in HCl, NaOH solution, river water, seawater or homemade seawater for 16 weeks and the degradation mechanism was investigated by the changes in weight loss rate, degree of substitution, hydrophilicity, molecular structure and surface morphology. The results showed that the degradation of CA tow and film were the fastest in NaOH solution; the weight loss rates after 16 weeks were 40.29% and 39.63%, respectively, followed by HCl solution, and the degradation performance of CA tow was better than that of film. After 16 weeks of degradation in river water, seawater and homemade seawater, all the weight loss rates were less than 3%. In summary, this study illustrated that the environmental acidity, basicity and high concentration of inorganic salts had a critical promotion effect on the non-enzymatic hydrolysis of CA, whereas the number and type of microorganisms were the key factors affecting the biodegradation of CA.

A Comparative Analysis of Pervaporation and Membrane Distillation Techniques for Desalination Utilising the Sweeping Air Methodology with Novel and Economical Pervaporation Membranes

This study used the sweeping air approach to conduct a comparative analysis of pervaporation (PV) and membrane distillation (MD) in the context of desalinating saline/hypersaline water. An experimental setup of the sweeping air arrangement was designed and built at a laboratory size to conduct the research. The desalination process using PV used innovatively designed cellulose acetate (CA) membranes specifically adapted for this purpose. Conversely, in the studies involving MD, hydrophobic polytetrafluoroethylene (PTFE) membranes were utilised. CA membranes were fabricated in our laboratory using the phase inversion approach. The physicochemical characteristics of the membranes were assessed using many methodologies, including FTIR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), contact angle measurement, and water uptake analysis. This facilitated a more comprehensive comprehension of the impact of the alkaline treatment on these features. The variables that were examined included the kind of membrane, the pore size of the PTFE membrane, the composition of the casting solution of CA, the concentration of the feed solution, the temperature of the feed, and the temperature of the condenser cooling water. The morphologies of the membranes were examined using SEM. The study's findings indicated that the use of MD resulted in a greater flow and a remarkable percentage of salt rejection (% SR). Furthermore, it was observed that the flux was positively correlated with the feed temperature, while it exhibited an inverse relationship with the cooling water temperature. Moreover, it was observed that the impact of the pore size of the PTFE membrane on the desalination process was found to be minimal. The most optimal outcomes obtained were 13.35 kg/m2 h with a percentage salt rejection (% SR) of 99.86, and 17.96 kg/m2 h with a % SR of 99.83 at a temperature of 70 °C, while using MD and PV technologies, respectively. Furthermore, both methods demonstrated the capability to desalinate very salty solutions with a salinity level of up to 160 g/L, thereby yielding potable water in a single step.

Enhancing the Photocatalytic Activity of Zirconium-Based Metal-Organic Frameworks Through the Formation of Mixed-Valence Centers

Despite the desirability of metal-organic frameworks (MOFs) as heterogeneous photocatalysts, current strategies available to enhance the performance of MOF photocatalysts are complicated and expensive. Herein, a simple strategy is presented for improving the activity of MOF photocatalysts by regulating the atomic interface structure of the metal active sites on the MOF. In this study, MOF (PCN-222) is hybridized with cellulose acetate (CA@PCN-222) through an optimized atomic interface strategy, which lowers the average valence state of Zr ions. The electronic metal-support interaction mechanism of CA@PCN-222 is revealed by evaluating the photocatalytic CO2 reduction reaction (CO2 RR). The experimental results suggested that the electron migration efficiency at the atomic interface of the MOFs strongly coupled with cellulose is significantly improved. In particular, the CO2 RR to formate activity of CA@PCN-222 photocatalyst greatly increased from 778.2 to 2816.0 µmol g-1 compared with pristine PCN-222 without cellulose acetate. The findings suggest that the strongly coupled metal-ligand moiety at the atomic interface of MOFs may play a synergistic role in heterogeneous catalysts.

Dual-mode security authentication of SrAl2 O4 :Eu,Dy phosphor encapsulated in electrospun cellulose acetate nanofibrous films

Photochromic inks have been an attractive authentication strategy to improve the anti-counterfeiting efficiency of commercial products. However, recent reports have shown significant disadvantages with photochromic inks, including poor durability and high cost. In this context, we developed novel photochromic nanofibres for advanced anti-counterfeiting applications. Lanthanide-doped strontium aluminate (LdSA) nanoparticles (NPs) were prepared and immobilized into electrospun cellulose acetate nanofibres (CANF). Authentication materials immobilized with inorganic photochromic agents can warranty durability and photostability. Therefore, the ultraviolet-stimulated photochromism of LdSA-encapsulated cellulose acetate nanofibres (LdSA@CANF) demonstrated high reversibility and photostability. A broad range of cellulose acetate nanofibres with unique emission characteristics was developed when applying different ratios of LdSA NPs. LdSA@CANF appeared colourless under visible daylight, whereas a green emission was monitored under ultraviolet-light illumination. The shape and chemical content of the photochromic fibrous films were examined using various analytical techniques. The mechanical characteristics of LdSA@CANF-coated paper were investigated. The emission wavelength was detected at 514 nm to designate green colour, whereas the excitation wavelength was detected at 369 nm to indicate transparency. The prepared cellulose acetate nanofibrous film can be described as an efficient strategy for the anti-counterfeiting of commercialized items.

In Situ Decoration of Bi2S3 Nanosheets on Zinc Oxide/Cellulose Acetate Composite Films for Photodegradation of Dyes under Visible Light Irradiation

A novel Bi2S3-zinc oxide/cellulose acetate composite film was prepared through a blending-wet phase conversion and in situ precipitate method. The results revealed that the incorporation of Bi2S3 in the film increased the cavity density and uniformity, which provided additional space for the growth of active species and improved the interaction between dye pollutants and active sites. Zinc oxide acted as a mediator to facilitate the separation of electron-hole pairs effectively preventing their recombination, thus reducing the photo-corrosion of Bi2S3. As a result, the Bi2S3-ZnO/CA composite film exhibited favorable photocatalytic activity in the degradation of various dyes. Additionally, the composite film displayed effortless separation and recovery without the need for centrifugation or filtration, while maintaining its exceptional catalytic performance even after undergoing various processes.

Electrosprayed Core (Cellulose Acetate)-Shell (Polyvinylpyrrolidone) Nanoparticles for Smart Acetaminophen Delivery

Smart drug delivery, through which the drug molecules are delivered according to the requests of human biological rhythms or by maximizing drug therapeutic effects, is highly desired in pharmaceutics. Many biomacromolecules have been exploited for this application in the past few decades, both in industry and laboratories. Biphasic release, with an intentional pulsatile release and a following extended release stage, represents a typical smart drug delivery approach, which aims to provide fast therapeutic action and a long time period of effective blood drug concentration to the patients. In this study, based on the use of a well-known biomacromolecule, i.e., cellulose acetate (CA), as the drug (acetaminophen, ATP)-based sustained release carrier, a modified coaxial electrospraying process was developed to fabricate a new kind of core-shell nanoparticle. The nanoparticles were able to furnish a pulsatile release of ATP due to the shell polyvinylpyrrolidone (PVP). The time cost for a release of 30% was 0.32 h, whereas the core-shell particles were able to provide a 30.84-h sustained release of the 90% loaded ATP. The scanning electron microscope and transmission electron microscope results verified in terms of their round surface morphologies and the obvious core-shell double-chamber structures. ATP presented in both the core and shell sections in an amorphous state owing to its fine compatibility with CA and PVP. The controlled release mechanisms of ATP were suggested. The disclosed biomacromolecule-based process-structure-performance relationship can shed light on how to develop new sorts of advanced nano drug delivery systems.

Active Cellulose Acetate/Chitosan Composite Films Prepared Using Solution Blow Spinning: Structure and Electrokinetic Properties

Cellulose acetate (CA), a very promising derivative of cellulose, has come into the focus of research due to its highly desired good film-forming ability for food packaging applications. Frequently, this derivative is used in combination with other compounds (polymers, nanoparticles) in order to obtain active materials. Here, we report the preparation of thin films made of cellulose acetate loaded with chitosan (CS) using the solution blow spinning (SBS) method. Films are prepared by SBS processing of the polymers mixture solution, considering the following variables: (i) the concentration of cellulose acetate and chitosan in the solution and (ii) the solvent system consisting of acetic or formic acid. The prepared materials are characterized in terms of physical properties, roughness (optical profilometer), porosity, wettability (contact angle measurements), chemical structure (Fourier transform infrared spectrometry), and electrokinetic properties (zeta potential). SBS enables the preparation of CA/CS films with high water vapor permeability, high porosity, and also higher water contact angle compared with pure CA films. The electrokinetic properties of composites are influenced by the inclusion of chitosan, which causes a shift of the isoelectric point (IEP) towards higher pH values, but the magnitude of the shift is not in correlation with chitosan concentration. Adsorption kinetic studies using bovine serum albumin (BSA) as a model protein reveal that chitosan modified cellulose acetate films manifest low affinity towards proteins that suggests prevention of biofilm formation on its surface.

Effect of Cellulose-Based Bioplastics on Current LDPE Recycling

The increased use of bioplastics in the market has led to their presence in municipal solid waste streams alongside traditional fossil-based polymers, particularly low-density polyethylene (LDPE), which bioplastics often end up mixed with. This study aimed to assess the impact of cellulose acetate plasticized with triacetin (CAT) on the mechanical recycling of LDPE. LDPE-CAT blends with varying CAT content (0%, 1%, 5%, 7.5%, and 10% by weight) were prepared by melt extrusion and analyzed using scanning electron microscopy, Fourier-transform infrared spectroscopy, thermal analysis (thermogravimetric and differential scanning calorimetry), dynamic rheological measurements, and tensile tests. The results indicate that the presence of CAT does not significantly affect the chemical, thermal, and rheological properties of LDPE, and the addition of CAT at different levels does not promote LDPE degradation under typical processing conditions. However, the addition of CAT negatively impacts the processability and mechanical behavior of LDPE, resulting in the reduced quality of the recycled material. Thus, the presence of cellulose-based bioplastics in LDPE recycling streams should be avoided, and a specific sorting stream for bioplastics should be established.

Transparent Figures: Researching and Preserving Objects of Cellulose Acetate

In 1935, the Deutsches Hygiene-Museum Dresden began to produce the so-called Transparent Figures, which became icons of the 20th century. This study aims to explore the effects of external agents such as humidity and temperature on the aging mechanism of the materials of the Transparent Figures and to slow it down through preventive measures. The focus is on cellulose acetate (CA), which was used for the outer skin of the Transparent Figures. The original objects were investigated using FTIR, Raman, and GC-MS. On some Transparent Figures, liquid leakage of additives occurs when the relative humidity rises above 50-60% RH and is accompanied by a release of acetic acid. Based on these findings, original CA used for the production of the Transparent Figures was artificially re-aged at 70 °C while varying the relative humidity. The specimens were analyzed with colorimetry and GC-MS. Additive content, degree of substitution and degree of polymerization were determined. The results showed that the degradation is slowed down at 30% RH compared to aging at 50% RH or 70% RH. Thus, lowering the relative humidity seems effective in slowing down the degradation of the CA of the Transparent Figures. A relative humidity of 30% RH and a temperature of 15 °C are recommended.

Influence of Weathering on the Degradation of Cellulose Acetate Microplastics Obtained from Used Cigarette Butts

Cellulose acetate is used in many applications, including for cigarette filters. Unfortunately, unlike cellulose, its (bio)degradability is under question, yet it often ends up uncontrolled in the natural environment. The main purpose of this study is to compare the effects of weathering on two types of cigarette filter (classic filters and newer filters that have more recently arrived on the market) following their use and disposal in nature. Microplastics were prepared from polymer parts of used (classic and heated tobacco products-HTP) cigarettes and artificially aged. TG/DTA, FTIR, and SEM analyses were performed both before and after the aging process. Newer tobacco products contain an additional film made of a poly(lactic acid) polymer which, like cellulose acetate, burdens the environment and poses a risk to the ecosystem. Numerous studies have been conducted on the disposal and recycling of cigarette butts and cigarette butt extracts, revealing alarming data that have also influenced the decisions of the EU, who addressed the disposal of tobacco products in the EU Directive (EU) 2019/904. Despite this, there is still no systematic analysis in the literature evaluating the impact of weathering (i.e., accelerated aging) on the degradation of cellulose acetate in classic cigarettes compared with that in newer tobacco products that have recently appeared on the market. This is of particular interest given that the latter have been promoted as being healthier and environmentally friendly. The results show that in cellulose acetate cigarette filters the particle size decreased after accelerated aging. Also, the thermal analysis revealed differences in the behavior of the aged samples, while the FTIR spectra showed no shifts in the position of the peaks. Organic substances break down under UV light, which can be seen by measuring the color change. The PLA film was found to be more stable than cellulose acetate under the influence of UV light.

Preparation and Characterization of Porous Cellulose Acetate Nanofiber Hydrogels

The currently reported methods for preparing cellulose acetate hydrogels use chemical reagents as cross-linking agents, and the prepared ones are non-porous structured cellulose acetate hydrogels. Nonporous cellulose acetate hydrogels limit the range of applications, such as limiting cell attachment and nutrient delivery in tissue engineering. This research creatively proposed a facile method to prepare cellulose acetate hydrogels with porous structures. Water was added to the cellulose acetate-acetone solution as an anti-solvent to induce the phase separation of the cellulose acetate-acetone solution to obtain a physical gel with a network structure, where the cellulose acetate molecules undergo re-arrangement during the replacement of acetone by water to obtain hydrogels. The SEM and BET test results showed that the hydrogels are relatively porous. The maximum pore size of the cellulose acetate hydrogel is 380 nm, and the specific surface area reaches 62 m²/g. The porosity of the hydrogel is significantly higher than that of the cellulose acetate hydrogel reported in the previous literature. The XRD results show that the nanofibrous morphology of cellulose acetate hydrogels is caused by the deacetylation reaction of cellulose acetate.

Innovative Fibrous Materials Loaded with 5-Nitro-8-hydroxyquinoline via Electrospinning/Electrospraying Demonstrate Antioxidant, Antimicrobial and Anticancer Activities

A new type of fibrous mat based on a cellulose derivative-cellulose acetate (CA) or CA and water-soluble polymers (polyvinylpyrrolidone, PVP or poly(vinyl alcohol), PVA)-loaded with the model drug 5-nitro-8-hydroxyquinoline (5N) was fabricated via electrospinning or electrospinning in conjunction with electrospraying. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), water contact angle measurements and ultraviolet-visible spectroscopy (UV-Vis) were used for the complex characterization of the obtained novel material. The decoration of CA fibers with a water-soluble polymer containing the drug resulted in the facilitation of wetting and fast drug release. The 5N-containing fibrous material showed antioxidant activity. Moreover, the proposed materials' antibacterial and antifungal properties were tested against S. aureus, E. coli, P. aeruginosa and C. albicans. Well-distinguished, sterile zones with diameters above 3.5 cm were observed around all 5N-containing mats. The mats' cytotoxicity toward HeLa carcinoma cells and normal mouse BALB/c 3T3 fibroblasts was assessed. The 5N-in-CA, PVP,5N-on-(5N-in-CA) and PVA,5N-on-(5N-in-CA) fibrous mats possessed anticancer efficacies and much lower levels of toxicity against normal cells. Therefore, the as-created novel electrospun materials, which are based on polymers loaded with the drug 5N via electrospinning/electrospraying, can potentially be applied for topical wound healing and for local cancer therapy.

Fabrication of Cellulose Acetate-Based Proton Exchange Membrane with Sulfonated SiO2 and Plasticizers for Microbial Fuel Cell Applications

Developing a hybrid composite polymer membrane with desired functional and intrinsic properties has gained significant consideration in the fabrication of proton exchange membranes for microbial fuel cell applications. Among the different polymers, a naturally derived cellulose biopolymer has excellent benefits over synthetic polymers derived from petrochemical byproducts. However, the inferior physicochemical, thermal, and mechanical properties of biopolymers limit their benefits. In this study, we developed a new hybrid polymer composite of a semi-synthetic cellulose acetate (CA) polymer derivate incorporated with inorganic silica (SiO₂) nanoparticles, with or without a sulfonation (-SO₃H) functional group (sSiO₂). The excellent composite membrane formation was further improved by adding a plasticizer (glycerol (G)) and optimized by varying the SiO₂ concentration in the polymer membrane matrix. The composite membrane's effectively improved physicochemical properties (water uptake, swelling ratio, proton conductivity, and ion exchange capacity) were identified because of the intramolecular bonding between the cellulose acetate, SiO₂, and plasticizer. The proton (H⁺) transfer properties were exhibited in the composite membrane by incorporating sSiO₂. The composite CAG-2% sSiO₂ membrane exhibited a higher proton conductivity (6.4 mS/cm) than the pristine CA membrane. The homogeneous incorporation of SiO₂ inorganic additives in the polymer matrix provided excellent mechanical properties. Due to the enhancement of the physicochemical, thermal, and mechanical properties, CAG-sSiO₂ can effectively be considered an eco-friendly, low-cost, and efficient proton exchange membrane for enhancing MFC performance.

Cellulose Acetate-Supported Copper as an Efficient Sustainable Heterogenous Catalyst for Azide-Alkyne Cycloaddition Click Reactions in Water

A new sustainable heterogeneous catalyst for copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC) was investigated. The preparation of the sustainable catalyst was carried out through the complexation reaction between the polysaccharide cellulose acetate backbone (CA) and copper(II) ions. The resulting complex [Cu(II)-CA] was fully characterized by using different spectroscopic methods such as Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Ultraviolet-visible (UV-vis), and Inductively Coupled Plasma (ICP) analyses. The Cu(II)-CA complex exhibits high activity in the CuAAC reaction for substituted alkynes and organic azides, leading to a selective synthesis of the corresponding 1,4-isomer 1,2,3-triazoles in water as a solvent and working at room temperature. It is worth noting that this catalyst has several advantages from the sustainable chemistry point of view including no use of additives, biopolymer support, reactions carried out in water at room temperature, and easy recovery of the catalyst. These characteristics make it a potential candidate not only for the CuAAC reaction but also for other catalytic organic reactions.

Functionalisation of Electrospun Cellulose Acetate Membranes with PEDOT and PPy for Electronic Controlled Drug Release

Controlled drug release via electrical stimulation from drug-impregnated fibres was studied using electrospun cellulose acetate (CA) membranes and encapsulated ibuprofen (IBU). This research outlines the influence of polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT)-functionalised CA membranes and their suitability for dermal electronic-controlled drug release. Micro Raman analysis confirmed polymer functionalisation of CA membranes and drug incorporation. Scanning electron microscopy (SEM) images evidenced the presence of PPy and PEDOT coatings. The kinetic of drug release was analysed, and the passive and active release was compared. In the proposed systems, the drug release is controlled by very low electrical potentials. A potential of -0.3 V applied to membranes showed the ibuprofen retention, and a positive potential of +0.3 V, +0.5 V, or +0.8 V, depending on the conductive polymer and membrane configuration, enhanced the drug release. A small adhesive patch was constructed to validate this system for cutaneous application and verified an "ON/OFF" ibuprofen release pattern from membranes.

Magnesium Ortho-Vanadate/Magnesium Oxide/Graphene Oxide Embedded through Cellulose Acetate-Based Films for Wound Healing Applications

A multifunctional nano-films of cellulose acetate (CA)/magnesium ortho-vanadate (MOV)/magnesium oxide/graphene oxide wound coverage was fabricated. Through fabrication, different weights of the previously mentioned ingredients were selected to receive a certain morphological appearance. The composition was confirmed by XRD, FTIR, and EDX techniques. SEM micrograph of Mg₃(VO₄)₂/MgO/GO@CA film depicted that there was a porous surface with flattened rounded MgO grains with an average size of 0.31 µm was observed. Regarding wettability, the binary composition of Mg₃(VO₄)₂@CA occupied the lowest contact angle of 30.15 ± 0.8^o, while pure CA represents the highest one at 47.35 ± 0.4°. The cell viability % amongst the usage of 4.9 µg/mL of Mg₃(VO₄)₂/MgO/GO@CA is 95.77 ± 3.2%, while 2.4 µg/mL showed 101.54 ± 2.9%. The higher concentration of 5000 µg/mL exhibited a viability of 19.23%. According to optical results, the refractive index jumped from 1.73 for CA to 1.81 for Mg₃(VO₄)₂/MgO/GO@CA film. The thermogravimetric analysis showed three main stages of degradation. The initial temperature started from room temperature to 289 °C with a weight loss of 13%. On the other hand, the second stage started from the final temperature of the first stage and end at 375 °C with a weight loss of 52%. Finally, the last stage was from 375 to 472 °C with 19% weight loss. The obtained results, such as high hydrophilic behavior, high cell viability, surface roughness, and porosity due to the addition of nanoparticles to the CA membrane, all played a significant role in enhancing the biocompatibility and biological activity of the CA membrane. The enhancements in the CA membrane suggest that it can be utilized in drug delivery and wound healing applications.

Cellulose Acetate Microbeads for Controlled Delivery of Essential Micronutrients

The controlled delivery of micronutrients to soil and plants is essential to increase agricultural yields. However, this is today achieved using fossil fuel-derived plastic carriers, posing environmental risks and contributing to global carbon emissions. In this work, a novel and efficient way to prepare biodegradable zinc-impregnated cellulose acetate beads for use as controlled release fertilizers is presented. Cellulose acetate solutions in DMSO were dropped into aqueous antisolvent solutions of different zinc salts. The droplets underwent phase inversion, forming solid cellulose acetate beads containing zinc, as a function of zinc salt type and concentration. Even higher values of zinc uptake (up to 15.5%) were obtained when zinc acetate was added to the cellulose acetate-DMSO solution, prior to dropping in aqueous zinc salt antisolvent solutions. The release profile in water of the beads prepared using the different solvents was linked to the properties of the counter-ions via the Hofmeister series. Studies in soil showed the potential for longer release times, up to 130 days for zinc sulfate beads. These results, together with the efficient bead production method, demonstrate the potential of zinc-impregnated cellulose acetate beads to replace the plastic-based controlled delivery products used today, contributing to the reduction of carbon emissions and potential environmental impacts due to the uptake of plastic in plants and animals.

Small Butt Harmful: Individual- and Population-Level Impacts of Cigarette Filter Particles on the Deposit-Feeding Polychaete Capitella teleta

In the marine environment, discarded cigarette filters (CFs) deteriorate and leach filter-associated chemicals. The study aim was to assess the effects of smoked CFs (SCFs) and non-smoked CFs (NCFs) particles on individual life-history traits in the deposit-feeding polychaete Capitella teleta and extrapolate these to possible population-level effects. C. teleta was exposed to sediment-spiked particles of NCFs and SCFs at an environmentally realistic concentration (0.1 mg particles g^-1 dw sed) and a 100-fold higher (10 mg particles g^-1 dw sed) concentration. Experimental setup incorporated 11 individual endpoints and lasted approximately 6 months. There were significant effects on all endpoints, except from adult body volume and egestion rate, in worms exposed to 10 mg SCF particles g^-1 dw sed. Although not statistically significant, there was ≥50% impact on time between reproductive events and number of eggs per female at 0.1 mg SCF particles g^-1 dw sed. None of the endpoints was significantly affected by NCFs. Results suggest that SCFs are likely to affect individual life-history traits of C. teleta, whereas the population model suggests that these effects might not transform into population-level effects. The results further indicate that chemicals associated with CFs are the main driver causing the effects rather than the CF particles.

Wastewater from the Arenga Starch Industry as a Potential Medium for Bacterial Cellulose and Cellulose Acetate Production

Wastewater from the Arenga starch industry (WWAS) contains a high chemical oxygen demand (COD) concentration, so it has to be treated before being discharged into water bodies. Therefore, the purpose of this study was to utilize WWAS as a medium for bacterial cellulose (BC) and cellulose acetate (CA) production. This study consisted of the production of BC through fermentation and the production of CA through acetylation. Fermentation was conducted under static batch conditions with various initial pHs and sucrose additions, while acetylation was conducted with various BC-acetic anhydride ratios. The results of this study showed that the maximum BC production of 505.6 g/L of the culture medium was obtained under the optimal conditions of a sucrose addition of 200 g/L, an initial medium pH of 4.5, and a cultivation time of 14 d. Furthermore, a BC-acetic anhydride ratio of 1:3 resulted in CA being suitable as a biofilm raw material with a yield of 81.49%, an acetyl content of 39.82%, a degree of substitution of 2.456, and a degree of crystallinity of 36.7%. FT-IR, ¹H and ¹³C NMR, XRD, and SEM analyses confirmed the successful process of acetylation of BC to CA.

Development of a Method for Peeling Off Paper from Celluloid Pictures for Animation Films

During the storage of celluloid pictures for animation films over half a century, an interleave paper adhered to acrylic paint. The purpose of this study is to establish a methodology to cleanly remove the paper from the paint. A layered film, a replica of the celluloid pictures, adhered with paper was prepared and immersed in water or ethanol. The effect of these solvents on the peeling behavior was investigated using a peel test. The maximum peel force for the dry layered film in was distributed at ~0.5 N, independently of the peel speed. The peel force was significantly reduced after the layered film was immersed in pure water or ethanol. A morphological observation revealed that the dry paper was peeled off via the cohesive failure of the paper. After the layered film was immersed in pure water, the paper was also peeled off via cohesive failure. The layered film immersed in ethanol was peeled off at the paper/paint interface. To clear the effect of the volume change in the paint on peel behavior, the relative volume was determined via image analysis. The relative volume of paint was 1.56 in pure water and 1.37 in ethanol. It can be considered that the large difference in the volume of paint induces a large shear stress at the paint/paper interface.

Impact of Ag/ZnO Reinforcements on the Anticancer and Biological Performances of CA@Ag/ZnO Nanocomposite Materials

In this study, an unpretentious, non-toxic, and cost-effective dissolution casting method was utilized to synthesize a group of anticancer and biologically active hybrid nanocomposite materials containing biopolymer cellulose acetate. Pristine ZnO and Ag_{(0.01, 0.05, 0.1)}/ZnO hybrid nanofillers based on variable Ag NP loadings were prepared via green procedures in the presence of gum arabic (GA). The chemical structures and the morphological features of the designed nanocomposite materials were investigated by PXRD, TEM, SEM, FTIR, TGA, and XPS characterization techniques. The characterization techniques confirmed the formation of CA@Ag_{(0.01, 0.05, 0.1)}/ZnO hybrid nanocomposite materials with an average crystallite size of 15 nm. All investigated materials showed two degradation steps. The thermal stability of the fabricated samples was ranked in the following order: CA/ZnO < CA@Ag_(0.01)/ZnO < CA@Ag_(0.05)/ZnO = CA@Ag_(0.1)/ZnO. Hence, the higher Ag doping level slightly enhanced the thermal stability. The developed nanocomposites were tested against six pathogens and were used as the target material to reduce the number of cancer cells. The presence of Ag NPs had a positive impact on the biological and the anticancer activities of the CA-reinforced Ag/ZnO composite materials. The CA@Ag_(0.1)/ZnO hybrid nanocomposite membrane had the highest antimicrobial activity in comparison to the other fabricated materials. Furthermore, the developed CA@Ag_(0.1)/ZnO hybrid nanocomposite material effectively induced cell death in breast cancer.

Modification of Cellulose Acetate Microfiltration Membranes Using Graphene Oxide-Polyethyleneimine for Enhanced Dye Rejection

Pressure-based membrane processes represent excellent water resource recovery prospects from industrial waste streams. In contrast with conventional pretreatment technologies, studies have shown that membrane pretreatment applications, such as microfiltration (MF), are more cost-effective and improve the results of the overall treatment processes. Hence, enhancing rejection efficiency of MF will enhance the performance of any downstream treatment processes. In this study, 0.45 µm cellulose acetate (CA) microfiltration membranes were modified by vacuum filtration-assisted layer-by-layer deposition of bilayers composed of negatively charged graphene oxide (GO) and positively charged polyethyleneimine (PEI). The performance of 1-, 2-, and 4-bilayer GO-PEI-modified membranes were investigated for their dye-rejection of anionic eriochrome black T (EBT) dye and cationic methylene blue (MB) dye in a cross-flow membrane module. As the number of bilayers on the membrane increased, the membrane thicknesses increased, and the deionized (DI) water flux through the membranes decreased from 4877 LMH/bar for the control (no bilayer) membrane to 2890 LMH/bar for the 4-bilayer membrane. Conversely, the dye-rejection performance of the modified membranes increased as increasing bilayers of GO-PEI deposited on the membranes. The anionic EBT dye saw superior rejection (~90% rejection) compared to the cationic MB dye (~80% rejection), which can be attributable to the electrostatic repulsion between the negatively charged GO surface and anionic EBT dye. After 50% recovery of the saline and dye-laden feed water, there was an observed drop in DI water fluxes of ~40-41% and 36%, respectively. There was also a slight increase in EBT dye-rejection during the composite feed-water experiments, attributed to the precipitation of salts on the membrane feed side or pore spaces, which subsequently reduce the membrane pore sizes.

Cellulose-Acetate-Based Films Modified with Ag2O and ZnS as Nanocomposites for Highly Controlling Biological Behavior for Wound Healing Applications

For wound healing, functional films with certain physicochemical and biological properties are needed. Thus, the current work aimed to fabricate multifunctional materials comprising metal oxide nanoparticles loaded with an efficient polymer to be used as dressing material. A composite containing polymeric phases of cellulose acetate (CA) blended with zinc sulfide (ZnS), silver oxide (Ag₂O), and graphene oxide (GO) was successfully synthesized. The prepared composite crystallinity was studied using the X-ray diffraction technique (XRD). Further, the functional groups and the elemental analysis were investigated using Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDX). Furthermore, the surface morphology was studied using scanning electron microscopy (SEM) to obtain the shape and size of particles. SEM showed that the particles were formed in wide distribution in the range of 18-915 nm with an average size of 235 nm for Ag₂O/ZnS/GO/CA. The particle size of Ag₂O in the CA film was in the range between 19 and 648 nm with an average size of 216 nm, while the particle size of ZnS in CA was in the range of 12-991 nm with an average age particle size of 158 mm. In addition, EDX, based on SEM investigation, detected high carbon and oxygen quantities at around 94.21% of the composite. The contact angle decreased and reached 26.28° ± 2.12° in Ag₂O/ZnS/CA. Furthermore, thermogravimetric analysis (TGA) was used to investigate the thermal stability, and the composition was thermally stable until 300 °C. Moreover, the cell viability of "normal lung cells" reached 102.66% in vitro at a concentration of 1250 µg/mL. The antibacterial activity of Ag₂O/ZnS/GO/CA was also detected against E. coli with a zone of inhibition reaching 17.7 ± 0.5 mm. Therefore, the composite can be used in biomedical applications due to its biocompatibility and antibacterial activity.

Bioactive cellulose acetate nanofiber loaded with annatto support skeletal muscle cell attachment and proliferation

Electrospinning emerged as a promising technique to produce scaffolds for cultivated meat in function of its simplicity, versatility, cost-effectiveness, and scalability. Cellulose acetate (CA) is a biocompatible and low-cost material that support cell adhesion and proliferation. Here we investigated CA nanofibers, associated or not with a bioactive annatto extract (CA@A), a food-dye, as potential scaffolds for cultivated meat and muscle tissue engineering. The obtained CA nanofibers were evaluated concerning its physicochemical, morphological, mechanical and biological traits. UV-vis spectroscopy and contact angle measurements confirmed the annatto extract incorporation into the CA nanofibers and the surface wettability of both scaffolds, respectively. SEM images revealed that the scaffolds are porous, containing fibers with no specific alignment. Compared with the pure CA nanofibers, CA@A nanofibers showed increased fiber diameter (420 ± 212 nm vs. 284 ± 130 nm). Mechanical properties revealed that the annatto extract induces a reduction of the stiffness of the scaffold. Molecular analyses revealed that while CA scaffold favored C2C12 myoblast differentiation, the annatto-loaded CA scaffold favored a proliferative state of these cells. These results suggest that the combination of cellulose acetate fibers loaded with annatto extract may be an interesting economical alternative for support long-term muscle cells culture with potential application as scaffold for cultivated meat and muscle tissue engineering.

Kiwi extract-incorporated poly(ɛ-caprolactone)/cellulose acetate blend nanofibers for healing acceleration of burn wounds

Kiwi extract (KE) including different components such as quercetin, vitamins C and E, and actinides has been known as a debridement agent for burn wounds. In this study, electrospun poly(ɛ-caprolactone)/cellulose acetate blend nanofibers incorporating KE (PCL/CA/KE) were prepared and their performance was evaluated for healing acceleration of burn wounds. The physicochemical characterization of PCL/CA/KE nanofibers showed an average diameter of ∼420 nm, porosity of 70%, water contact angle of 61°, and water uptake of ∼220%. Moreover, the continuous release trend of KE from PCL/CA blend nanofibers happened during 24 h and the release mechanism was governed by the Fickian diffusion. Besides the cytocompatibility of PCL/CA/KE nanofibers, their in vivo experiments revealed that the bioactive wound dressing based on the sample has higher wound closure compared to KE after 21 days. Histopathology of wounds dressed by PCL/CA/KE nanofibers indicated epidermal formation along with a fully extended layer. Eventually, the obtained results confirmed that the PCL/CA/KE nanofibrous sample was a promising wound dressing for burn wound healing.

A Facile Strategy toward the Preparation of a High-Performance Polyamide TFC Membrane with a CA/PVDF Support Layer

In this study, polyamide (PA) thin-film composite (TFC) nanofiltration membranes were fabricated via interfacial polymerization on cellulose acetate (CA)/poly(vinylidene fluoride) (PVDF) support layers. Several types of CA/PVDF supports were prepared via the phase inversion method. With increasing CA, the PVDF membrane surface pore size decreased and hydrophilicity increased. The effect of the support properties on the performance and formation mechanism of PA films was systematically investigated via an interfacial polymerization (IP) process. The permselectivity of the resulting TFC membranes was evaluated using a MgSO4 solution. The results show that the desired polyamide TFC membrane exhibited excellent water flux (6.56 L/(m2·h·bar)) and bivalent salt ion rejection (>97%). One aim of this study is to explore how the support of CA/PVDF influences the IP process and the performance of PA film.

Preparation of Copper Ion Adsorbed Modified Montmorillonite/Cellulose Acetate Porous Composite Fiber Membrane by Centrifugal Spinning

The natural adsorption material montmorillonite (MMT) was selected, and cellulose acetate (CA) was used as the loading substrate to design and prepare a kind of green and environment-friendly recyclable porous composite fiber membrane with good heavy metal ion adsorption performance. Acetic acid modified montmorillonite (HCl-MMT), sodium dodecyl sulfonate modified montmorillonite (SDS-MMT), and chitosan modified montmorillonite (CTS-MMT) were prepared by inorganic modification and organic modification, and the porous MMT/CA composite fiber membrane was constructed by centrifugal spinning equipment. The morphological and structural changes of MMT before and after modification and their effects on porous composite fiber membranes were investigated. The morphology, structure, and adsorption properties of the composite fibers were characterized by scanning electron microscopy (SEM) and atomic absorption spectrometry (ASS). The experimental results showed that the maximum adsorption capacity of Cu²⁺ on the prepared 5 wt% CTS-MMT composite fiber membrane was 60.272 mg/g after 10 h static adsorption. The adsorption of Cu²⁺ by a porous composite fiber membrane conforms to the quasi-second-order kinetic model and Langmuir isothermal adsorption model. The main factor of the Cu²⁺ adsorption rate is chemical adsorption, and the adsorption mechanism is mainly monolayer adsorption.

Novel Magnetic Mixed Cellulose Acetate Matrix Membranes with Oxygen-Enrichment Potential

This work presents novel magnetic mixed cellulose-based matrix membranes that combine the advantages of a low-cost common polymer matrix, such as cellulose acetate (CA), and a low-cost magnetic filler. Moreover, the presented magnetic mixed CA matrix membranes were fabricated and used without applying an external magnetic field during either the membrane casting or the separating process. Poly(methylmethacrylate) and lithium chloride were used in order to improve the mechanical properties and porosity of the fabricated membranes. The iron-nickel magnetic alloys used were prepared through a simple chemical reduction method with unique morphologies (Fe₁₀Ni₉₀-starfish-like and Fe₂₀Ni₈₀-necklace-like). The novel magnetic mixed CA matrix membranes fabricated were characterized using different analysis techniques, including SEM, EDX, XRD, TGA, and FTIR-ATR analyses. Furthermore, the static water contact angle, membrane thickness, surface roughness, tensile strength, and membrane porosity (using ethanol and water) were determined. In addition, vibrating sample magnetometer (VSM) analysis was conducted and the oxygen transition rate (OTR) was studied. The magnetic mixed CA matrix membrane containing starfish-like Fe₁₀Ni₉₀ alloy was characterized by high coercivity (109 Oe) and an efficient 1.271 × 10^-5 cm³/(m²·s) OTR compared to the blank CA membrane with 19.8 Oe coercivity and no OTR. The effects of the polymeric matrix composition, viscosity, and compatibility with the alloys/fillers used on the structure and performance of the fabricated mixed CA matrix membranes compared to the previously used poly(ethersufone) polymeric matrix are discussed and highlighted. The novel magnetic mixed CA matrix membranes presented have good potential for use in the oxygen-enrichment process.

Biopolymer-Based Films Reinforced with Green Synthesized Zinc Oxide Nanoparticles

Nowadays, biopolymer-based films are being developed as an alternative to conventional plastic-based films, mainly because they are non-toxic, flexible, inexpensive, and widely available. However, they are restricted in their applications due to several deficiencies in their properties. Accordingly, the reinforcement of these materials with nanoparticles/nanofillers could overcome some of their shortcomings, especially those processed by green methods. Green synthesized zinc oxide nanoparticles (ZnO-NPs) are highly suggested to overcome these deficiencies. Therefore, the main aim of this work was to develop different biopolymer-based films from cellulose acetate (CA), chitosan (CH), and gelatin (GE) reinforced with ZnO-NPs prepared by casting, and to assess their different properties. The results show the improvements produced by the incorporation of ZnO-NPs (1% w/w) into the CA, CH, and GE systems. Thus, the water contact angles (WCAs) increased by about 12, 13, and 14%, while the water vapor permeability (WVP) decreased by about 14, 6, and 29%, the water solubility (WS) decreased by about 23, 6, and 5%, and the transparency (T) increased by about 19, 31, and 20% in the CA, CH, and GE systems, respectively. Furthermore, the mechanical properties were enhanced by increasing the ultimate tensile strength (UTS) (by about 39, 13, and 26%, respectively) and Young's modulus (E) (by about 70, 34, and 63%, respectively), thereby decreasing the elongation at the break (ε_max) (by about 56, 23, and 49%, respectively) and the toughness (by about 50, 4, and 30%, respectively). Lastly, the antioxidant properties were enhanced by 34, 49, and 39%, respectively.

Fabrication of Electrospun Cellulose Acetate/Nanoclay Composites for Pollutant Removal

The creation of eco-friendly clay-based composites for pollutant removal by adsorption still remains a challenge. This problem might be successfully solved by the development of electrospun polymer-clay composites. For the first time in this study, a one-step fabrication of cellulose acetate (CA) fibers filled with commercially available nanoclays (NCs) was described. The optimal ratio at which CA/NCs dispersions remained stable was accomplished by varying the nanoclay concentration with respect to CA. Furthermore, the selected solvent system and the electrospinning conditions allowed for the successful fabrication of electrospun CA/NC composites. It was found that the composites' surface morphology was not affected by the incorporated nanoclays and was the same as that of the electrospun CA fibers. The performed analyses clearly showed that CA and nanoclays did not react during the electrospinning process. It was found that the distribution of nanoclay layers probably was a mixture of intercalated and exfoliated structures. Notably, the type of the nanoclay strongly influenced the adsorption ability of CA/NC composites toward Cr(VI) ions and MB dye. These results suggested that the fabricated CA/NC composites are suitable for pollutant removal due to their specific structure.

Preparation and Phytotoxicity Evaluation of Cellulose Acetate Nanoparticles

The use of biocompatible and low-cost polymeric matrices to produce non-phytotoxic nanoparticles for delivery systems is a promising alternative for good practices in agriculture management and biotechnological applications. In this context, there is still a lack of studies devoted to producing low-cost polymeric nanoparticles that exhibit non-phytotoxic properties. Among the different polymeric matrices that can be used to produce low-cost nanoparticles, we can highlight the potential application of cellulose acetate, a natural biopolymer with biocompatible and biodegradable properties, which has already been used as fibers, membranes, and films in different agricultural and biotechnological applications. Here, we provided a simple and low-cost route to produce cellulose acetate nanoparticles (CA-NPs), by modified emulsification solvent evaporation technique, with a main diameter of around 200 nm and a spherical and smooth morphology for potential use as agrochemical nanocarriers. The non-phytotoxic properties of the produced cellulose acetate nanoparticles were proved by performing a plant toxic test by Allium cepa assay. The cytotoxicity and genotoxicity tests allowed us to evaluate the mitotic process, chromosomal abnormalities, inhibition/delay in root growth, and micronucleus induction. In summary, the results demonstrated that CA-NPs did not induce phytotoxic, cytotoxic, or genotoxic effects, and they did not promote changes in the root elongation, germination or in the mitotic, chromosomal aberration, and micronucleus indices. Consequently, the present findings indicated that CA-NPs can be potentially used as environmentally friendly nanoparticles.

Highlighting the Compositional Changes of the Sm2O3/MgO-Containing Cellulose Acetate Films for Wound Dressings

The development of wound dressing materials with appropriate specifications is still a challenge to overcome the current limitations of conventional medical bandages. In this regard, simple and fast methods are highly recommended, such as film casting. In addition, deliverable nanoparticles that can act to accelerate wound integration, such as samarium oxide (Sm₂O₃) and magnesium oxide (MgO), might represent a potential design with a novel compositional combination. In the present research, the casted film of cellulose acetate (CA) was mixed with different ratios of metal oxides, such as samarium oxide (Sm₂O₃) and magnesium oxide (MgO). The tests used for the film examination were X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The SEM graphs of CA films represent the surface morphology of Sm₂O₃@CA, MgO@CA, and Sm₂O₃/MgO/GO@CA. It was found that the scaffolds' surface contained a high porosity ratio with diameters of 1.5-5 µm. On the other hand, the measurement of contact angle exhibits a variable trend starting from 27° to 29° for pristine CA and Sm₂O₃/MgO/GO@CA. The cell viability test exhibits a noticeable increase in cell growth with a decrease in the concentration. In addition, the IC₅₀ was determined at 6 mg/mL, while the concentration of scaffolds of 20 mg/mL caused cellular growth to be around 106%.

Water Molecular Dynamics in the Porous Structures of Ultrafiltration/Nanofiltration Asymmetric Cellulose Acetate-Silica Membranes

This study presents the characterization of water dynamics in cellulose acetate-silica asymmetric membranes with very different pore structures that are associated with a wide range of selective transport properties of ultrafiltration (UF) and nanofiltration (NF). By combining 1H NMR spectroscopy, diffusometry and relaxometry and considering that the spin-lattice relaxation rate of the studied systems is mainly determined by translational diffusion, individual rotations and rotations mediated by translational displacements, it was possible to assess the influence of the porous matrix's confinement on the degree of water ordering and dynamics and to correlate this with UF/NF permeation characteristics. In fact, the less permeable membranes, CA/SiO2-22, characterized by smaller pores induce significant orientational order to the water molecules close to/interacting with the membrane matrix's interface. Conversely, the model fitting analysis of the relaxometry results obtained for the more permeable sets of membranes, CA/SiO2-30 and CA/SiO2-34, did not evidence surface-induced orientational order, which might be explained by the reduced surface-to-volume ratio of the pores and consequent loss of sensitivity to the signal of surface-bound water. Comparing the findings with those of previous studies, it is clear that the fraction of more confined water molecules in the CA/SiO2-22-G20, CA/SiO2-30-G20 and CA/SiO2-34-G20 membranes of 0.83, 0.24 and 0.35, respectively, is in agreement with the obtained diffusion coefficients as well as with the pore sizes and hydraulic permeabilities of 3.5, 38 and 81 kg h-1 m-2 bar-1, respectively, reported in the literature. It was also possible to conclude that the post-treatment of the membranes with Triton X-100 surfactants produced no significant structural changes but increased the hydrophobic character of the surface, leading to higher diffusion coefficients, especially for systems associated with average smaller pore dimensions. Altogether, these findings evidence the potential of combining complementary NMR techniques to indirectly study hydrated asymmetric porous media, assess the influence of drying post-treatments on hybrid CA/SiO2 membrane' surface characteristics and discriminate between ultra- and nano-filtration membrane systems.

Biopolymer-Based Films Reinforced with FexOy-Nanoparticles

Nowadays, natural polymer-based films are considered potentially environmentally friendly alternatives to conventional plastic films, due to many advantageous properties, including their easy processability, high flexibility, non-toxicity, low cost, high availability, and environmental safety. However, they are limited in their application by a number of shortcomings, including their high water solubility and vapor permeability as well as their poor opacity and low mechanical resistance. Thus, nanoparticles, such as green Fe_xO_y-NPs, can be used to overcome the drawbacks associated with these materials. Therefore, the aim of this study was to develop three different polymer-based films (gelatin-based, cellulose acetate-based and chitosan-based films) containing green synthesized Fe_xO_y-NPs (1.0% w/w of the initial polymer weight) as an additive to improve film properties. This was accomplished by preparing the different films using the casting method and examining their physicochemical, mechanical, microstructural, and functional characteristics. The results show that the incorporation of Fe_xO_y-NPs into the different films significantly enhanced their physicochemical, mechanical, and morphological properties as well as their antioxidant characteristics. Consequently, it was possible to produce suitable natural polymer-based films with potential applications across a wide range of industries, including functional packaging for food, antioxidants, and antimicrobial additives for pharmaceutical and biomedical materials as well as pesticides for agriculture.

Piezoelectric Nanogenerator Based on Electrospinning PVDF/Cellulose Acetate Composite Membranes for Energy Harvesting

The organic piezoelectric polymer polyvinylidene fluoride (PVDF) has attracted extensive research because of its excellent flexibility and mechanical energy-harvesting properties. Here, the electrospinning technique was taken to fabricate synthesized fiber membranes of a PVDF/cellulose acetate (CA) composite. The obtained PVDF/CA electrospun fiber membranes (EFMs) were employed to prepare a flexible nanogenerator. XRD and FTIR spectroscopy revealed the enhancement of piezoelectric behavior due to an increase in β-phase in PVDF/CA EFMs compared with cast films. The PVDF/CA fibers (mass ratio of PVDF to CA = 9:1) showed an output voltage of 7.5 V and a short-circuit current of 2.1 μA under mechanical stress of 2 N and frequency of 1 Hz, which were 2.5 and two times greater than those of the pure PVDF fibers, respectively. By charging a 4.7 µF capacitor for 15 min with the voltage generated by the PVDF/CA EFMs, nine LED lamps could be lit. The work provides an effective approach to enhancing the piezoelectric effects of PVDF for low-power electronic loading of macromolecule polymers.

Antibacterial and Antifungal Silver Nanoparticles with Tunable Size Embedded in Various Cellulose-Based Matrices

The aim of this study was to synthesize silver nanoparticles (AgNPs) using cellulose derivatives and to evaluate their antimicrobial potential. As effective reducing and stabilizing agents for AgNPs, cellulose derivatives, such as hydroxypropyl cellulose (HPC), methylcellulose (MC), ethylcellulose (EC), and cellulose acetate (CA), were used. Their ability to reduce silver ions as well as the size of the resulting AgNPs were compared. The formation and stability of the reduced AgNPs in the solution were monitored using UV-Vis analysis. The size, morphology, and charge of the AgNPs were evaluated. We found that, when using cellulosic derivatives, AgNPs with sizes ranging from 17 to 89 nm and different stabilities were obtained. The parameters, such as size and ζ potential indicate the stability of AgNPs, with AgNPs-CA and AgNPs-HPC being considered more stable than AgNPs-EC and AgNPs-MC since they show higher ζ potential values. In addition, the AgNPs showed antimicrobial activity against all reference strains and clinical isolates. MIC values between 0.0312 and 0.125 mM had a bactericidal effect on both Gram-positive and Gram-negative bacteria. The fungicidal effect was obtained at a MIC value of 0.125 mM. These results may provide rational support in the design of medical gauze products, including gauze pads, rolls, and sponges.

The Application of Cellulose Acetate Membranes for Separation of Fermentation Broths by the Reverse Osmosis: A Feasibility Study

Recently, there has been a special research focus on the bioconversion of glycerol to 1,3-propanediol (1,3-PD) due to its significance in the chemical industry. However, the treatment and separation of fermentation broths is a great challenge. Currently, the reverse osmosis (RO) process is a reliable state-of-the-art technique for separation of biological solutions. This study (as the first to do so) investigated the feasibility of separation of 1,3-PD broths with the use of cellulose acetate (CA) membrane by the RO process. The experiments were carried out using the installation equipped with the plate module, under the transmembrane pressure (TMP) and temperature of 1 MPa and 298 K, respectively. It was found that the used membrane was suitable for broth separation. Indeed, it was noted that 1,3-PD, as a target product, migrated through the membrane; meanwhile, other broth components were rejected in various degrees. Moreover, it was proven that retention of carboxylic acids tended to increase with increasing molecular weight, according to the following order: succinic acid > lactic acid > acetic acid > formic acid. With regards to ions, retention degree increased with the increase of ionic radius and decrease of diffusion coefficient. Finally, it was demonstrated that the CA membrane is resistant to irreversible fouling, which has a positive effect on the economic viability of the process.

Cellulose-Acetate Coating by Integrating Ester Group with Zinc Salt for Dendrite-Free Zn Metal Anodes

Zinc (Zn) metal is considered a potential anode owing to its high theoretical capacity, safety, and low cost. However, the dendrites and corresponding side reactions in aqueous electrolytes hinder their further development in environmentally-friendly energy storage. Herein, ion-affiliative cellulose acetate (CA) coating with Zn(CF₃ SO₃ )₂ is constructed on Zn anode (CAZ@Zn). Owing to the complexation effect between the polar ester group (CO) and Zn salt (Zn²⁺ ), the CAZ polymer coating enhances the hydrophilicity of the Zn anode and reduces the interfacial resistance, allowing the rapid Zn²⁺ diffusion and homogenizing the Zn deposition in an aqueous electrolyte to suppress zinc dendrite formation and growth. Therefore, the symmetric CAZ@Zn//CAZ@Zn battery achieves reversible plating/stripping over 2800 h at 1 mA cm^-2 with 1 mAh cm^-2 , about sevenfold higher than bare Zn. The full cell fabricated with an optimized Zn anode and the NH₄ V₄ O₁₀ cathode achieves substantially stable performance, superior to that of bare Zn. This work provides a straightforward, effective, and scalable method to suppress the zinc dendrites and corresponding side reactions for aqueous Zn-ions batteries.

Cellulose Acetate-Based High-Electrolyte-Uptake Gel Polymer Electrolyte for Semi-Solid-State Lithium-Oxygen Battery with Long-Cycling Stability

The lithium-oxygen battery has inspired great research interests owing to its ultrahigh theoretical energy density and has been considered as one of the promising secondary batteries. However, there are still some challenges in its practical application, like liquid organic electrolyte evaporation in the semi-open system and instability in the high-voltage oxidizing environment. In this work, a cellulose acetate-based gel polymer electrolyte (CA@GPE) is proposed, whose cross-linked microporous structure ensures the ultrahigh liquid electrolyte uptake of 2391%. The prepared CA@GPE exhibits a high lithium-ion transference number of 0.595, a satisfying ionic conductivity of 0.47 mS cm -1 and a wide electrochemical stability window up to 5.0 V. The Li//Li symmetric cell employing CA@GPE could cycle stably over 1200 h. The lithium-oxygen battery with CA@GPE presents a superb cycling lifetime of 370 cycles at 0.1 mA cm -2 under 0.25 mAh cm -2 . This work offers a possible strategy to realize long-cycling stability lithium-oxygen batteries.

Improvement of Antibacterial and Antifouling Properties of a Cellulose Acetate Membrane by Surface Grafting Quaternary Ammonium Salt

Through etherification reaction, epoxy propyl dimethyl dodecyl ammonium chloride (EPDMDAC) was grafted onto the surface of a cellulose acetate (CA) membrane to prepare a stable nonleaching antibacterial antifouling membrane (QCA-X). The results showed that with the extension of grafting reaction time, the quaternary ammonium salt groups on the membrane surface increased and the hydrophilicity was enhanced. Compared with those of the CA membrane, the filtration capacity and antifouling performance of the QCA-X membrane are improved. When the grafting time is 4 h, the water permeability and flux recovery rate of the QCA-4 membrane are increased by 139 and 21.5%, respectively. The QCA-X membrane showed excellent antibacterial performance, and the sterilization rate against S. aureus and E. coli was more than 99.99%. After four repeated antibacterial cycles, the bactericidal rates against S. aureus and E. coli were maintained at about 99.69 ± 0.02 and 99.98 ± 0.02%, respectively, with good antibacterial persistence. Moreover, the QCA-X membrane can effectively inhibit bacterial adhesion. Mild and simple EPDMDAC grafting modifications improve the antibacterial, antifouling, and antibioadhesion properties of the CA membrane, showing its application potential in long-term water treatment, especially in biofouling water treatment.

On the Thermochemical Transition Depression of Cellulose Acetate Composite Membranes

Gallic acid (GA) and quercetin (QU) are two important bioactive molecules with increased biomedical interest. Cellulose acetate (CA) is a polymer derived from cellulose and is used in various applications. In this work, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) were used to study the thermal behavior of electrospun CA membranes loaded with quercetin or gallic acid. It was found that gallic acid and quercetin depress the thermochemical transition (simultaneous softening and decomposition) of CA, in a mechanism similar to that of the glass transition depression of amorphous polymers by plasticizers. The extensive hydrogen bonding, besides the well-known effect of constraining polymer's softening by keeping macromolecules close to each other, has a secondary effect on the thermochemical transition, i.e., it weakens chemical bonds and, inevitably, facilitates decomposition. This second effect of hydrogen bonding can provide an explanation for an unexpected observation of this study: CA membranes loaded with quercetin or gallic acid soften at lower temperatures; however, at the same time, they decompose to a higher extent than pure CA. Besides optimization of CA processing, the fundamental understanding of the thermochemical transition depression could lead to the design of more sustainable processes for biomass recycling and conversion.