Cellulose Composite Films Research Articles

Physical and antibacterial properties of corn distarch phosphate/carboxymethyl cellulose composite films containing tea polyphenol

Antibacterial packaging films were developed by incorporating tea polyphenol (TP) into corn distarch phosphate (CDP)/carboxymethyl cellulose (CMC) films via solvent casting. Incorporation of TP had a great influence on the physical properties of the composite films. The prepared composite films were evaluated by scanning electron microscopy and Fourier transform infrared spectroscopy, and their physical properties, moisture barrier properties, and antibacterial activities were investigated. Microstructural studies revealed that the surface of the CDP/CMC/TP composite films became rough and uneven sponge-like. Attenuated total reflectance Fourier transform infrared exhibited interactions between TP and CDP/CMC films matrix was caused by hydrogen bonding. Addition of TP into CDP/CMC films improved the extensibility, toughness, and moisture barrier properties of the composite films greatly. The CDP/CMC/TP composite films showed excellent antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli. The CDP/CMC/TP films are promising functional packaging materials. Practical applications Tea polyphenol (TP) exhibits effective antioxidant and antibacterial properties, which can be extracted from tea. In this work, we successfully fabricated a novel antibacterial films containing TP, and improved the physical properties of the films. This study can provide a good candidate and a promising way for the development of active packaging material in food industry. Moreover, there is immense potential in the application of food preservation.

Effects of Formic Acid Treatment on Properties of Oil Palm Empty Fruit Bunch (OPEFB)-Based All Cellulose Composite (ACC) Films

Effects of Formic Acid Treatment on Properties of Oil Palm Empty Fruit Bunch (OPEFB)-Based All Cellulose Composite (ACC) Films

Polyoxometalate film simultaneously converts multiple low-value all-weather environmental energy to electricity

The conversion of low-value natural environmental energy into the clean and high-value electricity provides a promising approach for solving the energy crisis and environmental pollution. Using one device to directly convert all-weather environmental energy into electricity is an ideal goal and still remains a great challenge. Here, we assembled a simple and multifunctional device with the polyoxometalate (POM)/ethyl cellulose composite film on metal substrate, which generates electricity from multiple low-value all-weather environmental energy, including sunlight, wind and raindrops. For example, the optimal Mo72Cr30/ethyl cellulose composite film (Mo72Cr30 wt% = 71.4%) exhibits remarkable output performance with the responsivity of 176.3 μA W−1 under AM 1.5 G solar light, an average output of 4.48 μW m−2 from wind at a speed of 10 m s−1, and an average output of 0.25 μW m−2 from raindrops at a dripping rate of 7 mL min−1, as well as the better output power density of 6.32 μW m−2, 0.54 μW m−2 and 8.71 μW m−2 simultaneously driven by sunlight and wind, sunlight and raindrops, wind and raindrops, respectively. It also achieves an average output power density of 17.7 μW m−2, as well as long-term durability when it is simultaneously driven by sunlight, wind and raindrops, which exhibits 4 and 70 times than single wind and raindrops condition. For this composite film, the maximum power density is achieved at a very low resistance load of about 10 Ω. The output power arises from the high efficient transport of photo-generated electrons and electrostatic charges from Mo72Cr30 to metal substrate.

Preparation of multifunctional carboxymethyl cellulose-based films incorporated with chitin nanocrystal and grapefruit seed extract

Chitin nanocrystals (ChNC) were isolated from shrimp shells powder using acid hydrolysis and ammonium persulfate methods. Multifunctional carboxymethyl cellulose (CMC) composite films were prepared by adding ChNC and grapefruit seed extract (GSE), and their effects on the optical, mechanical, water vapor barrier, and antibacterial properties of CMC film were investigated. The isolated ChNC had a needle-like structure with a length of 340–370 nm and a diameter of 18–20 nm depending on the isolation method. The CMC films prepared with ChNC and GSE were transparent with high UV barrier properties. The addition of GSE reduced the strength (TS) and stiffness (EM) of CMC films by 10.4% and 30.3%, respectively, while the flexibility (EB) increased by 17.7%. However, when the ChNC was added, the TS and EM of CMC film increased by 19.7% and 58.7%, respectively, and the EB remained the same. The addition of ChNC reduced the water vapor permeability (WVP) of the CMC film by 27%. CMC films containing GSE also showed strong antibacterial activity against foodborne pathogenic bacteria, E. coli and L. monocytogenes.

Fabricating cellulose nanofibril from licorice residues and its cellulose composite incorporated with natural nanoparticles

It is important to make full utilization of industrial biomass residues. Pulp was prepared from licorice residues by soda-anthraquinone pulping followed by peroxyacetic acid bleaching. Cellulose nanofibril was obtained by enzymatic pretreatment followed by homogenization of the pulp (ETCNF). The effects of enzymatic pretreatment on ETCNF were investigated. Chitosan nanofibril (CHN) and lignin nanoparticles (LNPs) were prepared and used for ETCNF composites, respectively. The results showed that ETCNF exhibited clear nanofibrillar structure and a highly relative colloidal stability, and a much higher crystallinity index and thermal stability compared to TEMPO-medicated oxidized one; the cellulose composite films incorporated with CHN or LNPs exhibited good thermal stability and hydrophobicity. Compared with ETCNF film, ETCNF@LNPs-5.0% film showed higher UV-blocking ability and thermal stability, but reduced light transmittance, while ETCNF@CHN-5.0% film showed improved mechanical properties and similar light transmittance. This study would expend licorice residues as potential materials for CNF and its applications.

Synthesis and characterization of PVA/Starch/CMC composite films reinforced with walnut (Juglans regia L.) shell flour

Polyvinyl alcohol/Starch/Carboxymethyl cellulose (PSC) composite films were synthesized by solvent casting method using glycerol as plasticizer and citric acid as cross linking agent. The effect of different loadings of carboxymethyl cellulose (CMC) on thermal and tensile properties of PVA/Starch (PS) composites was investigated. The increasing concentration of CMC enhanced the thermal stability of PS composite films. PSC film at an optimum level of CMC showed the maximum tensile strength (36.56 ± 1.54 MPa) and was further chosen to analyze the effect of walnut shell flour (WSF) addition. PSC films reinforced with different amounts of WSF were analyzed by thermogravimetric analysis, UV absorption spectra, tensile testing, water absorption study and soil burial degradability test. The reinforcement of WSF showed a remarkable improvement in thermal stability and water resistant property of the films. Addition of WSF in PSC films reduced the degradability of films, with maximum percentage of weight loss obtained with 2% loading. Further, the tensile strength was found to be improved up to 6% level (41.09 ± 0.71 MPa). ANOVA of the tensile data recognized the considerable differences between the mean tensile strength from one composition to another (p < 0.05).

Self-assembling flexible 2D carbide MXene film with tunable integrated electron migration and group relaxation toward energy storage and green EMI shielding

Delaminated Ti3C2Tx (D-Ti3C2Tx) MXene films exhibit excellent electrochemical and electromagnetic interference (EMI) shielding performance. However, the low yield and easy oxidation of D-Ti3C2Tx nanosheet limit its commercial application. Herein, the flexible green multilayered Ti3C2Tx/hydroxyethyl cellulose (M-Ti3C2Tx/HEC) composite film was successfully fabricated through the filtration assisted self-assembly of M-Ti3C2Tx together with HEC. The film shows good cyclability as electrode materials for energy storage devices, which is mainly attributed to the construction of interconnected structures, where HEC was bonded to M-Ti3C2Tx. The electron migration and surface group play important roles in the process of charging and discharging. Meanwhile, the film shows excellent EMI shielding performance. Especially, dielectric loss analysis indicates that EM waves entering the film are mainly dissipated in the form of heat energy caused by electron migration. The effect of multilayer stacking indicates that the film present the trend of absorption-dominate green EMI shielding with the decrease of the stacking thickness. This work will provide new ideas for accelerating the utilization of the MXene-based energy storage and green EMI shielding materials.

Facile preparation of collagen fiber–glycerol-carboxymethyl cellulose composite film by immersing method

Carboxymethyl cellulose (CMC) and glycerol were added by immersing neutralized collagen fiber paste into CMC/glycerol aqueous solutions with different mass ratios, forming composite films. CMC decreased the glycerol adsorption by 49.5%. The presence of CMC formed rougher film surface and more compact internal structure. Glycerol increased the distances between collagen molecules and decreased the relative triple helix contents. The tensile strength and Young’s modulus of film in dry condition maximum respectively increased by 125% and 277% with the immersion in CMC (1.5%)/glycerol (4%) solution, compared to the sample immersed into pure glycerol solution, but mechanical properties decreased at high glycerol content. Besides, lower wet mechanical strength was observed as the addition of CMC, corresponding to the higher water swelling ratio of film. CMC also improved the shrinkage stability under boiling and the thermostability of film at a fixed glycerol level, but higher glycerol content caused the decrease of denaturation temperature of film.

Characterization of mechanical and barrier properties of bacterial cellulose, glycerol and polyvinyl alcohol (PVOH) composite films with eco-friendly UV-protective properties

Highly flexible composite films based on bacterial cellulose, glycerol and polyvinyl alcohol (PVOH) with UV barrier properties were developed. The open nanoscale network of bacterial cellulose allowed to combine it with glycerol and polyvinyl alcohol by immersion. This procedure kept intact the bacterial cellulose structure. The interactions among bacterial cellulose, glycerol and PVOH were analyzed using scanning electron microscopy, infrared spectroscopy, thermogravimetry and differential scanning calorimetry. In general, the addition of PVOH reinforced the bacterial cellulose matrix, meanwhile glycerol showed a significant plasticizing effect. Formulations with PVOH and glycerol reached a maximum value of 49.89% of elongation and a good resistance to rupture of 13.78 MPa. The water vapour permeability ranged from 1.87·10−11 to 2.04·10−10 g/m s Pa. The UV-VIS spectral analysis showed that glycerol decreased the transmittance in the UV area and polyvinyl alcohol enhanced the transparency values of the samples in the VIS region. The transmittance in the UV-A, UV-B and UV-C areas for films based on bacterial cellulose with glycerol reached up to 5.59, 2.4 and 0.57%, respectively.

Facile fabrication of cellulose composite films with excellent UV resistance and antibacterial activity

Research on biodegradable cellulose composite film with unique properties is of significance to alleviate current dependency on petroleum-based polymers, and to promote highly efficient utilization of lignocellulosic biomass. Lignin nanoparticles (LNPs) have been considered as a promising material for high value-added products. In this study, LNPs were prepared from corncob lignin via anti-solvent precipitation method, and then characterized by FTIR, TGA, AFM, and NMR. The CNF@CLNPs composite film was fabricated by blending CLNPs with CNF. The results showed that the CLNPs had an average diameter of about 118 nm, meanwhile the main structures and properties of corncob lignin were maintained. The CNF@CLNPs composite film exhibited a high ultraviolet resistance, and a good antibacterial activity against both Escherichia coli and Staphylococcus aureus. It is expected that the CNF@CLNPs composite film would have potential applications in outdoor materials and food packaging.

Enhanced corrosion protective performance of graphene oxide-based composite films on AZ31 magnesium alloys in 3.5 wt% NaCl solution

Constructing the film with a green corrosion inhibitor is the key to metal corrosion protection. This study reports an environmentally friendly graphene oxide (GO) and carboxymethyl cellulose (CMC) composite films (CMC@GO) with enhanced corrosion protection performance. The CMC@GO composite film was grown on AZ31 magnesium alloy by the layer-by-layer (LbL) assembly method. Fourier transform infrared (FT-IR) spectroscopy and the solid-state NMR Spectrometer reveal the successful modification of CMC on the surface of GO nanosheets. The chemical states and the surface morphology of the CMC@GO composite film were obtained from X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrochemical measurements and equivalent circuit fitting results demonstrate that the film containing GO composites has higher corrosion resistance than the film of undoped GO. The CMC@GO composite film exerted the corrosion inhibition effect of GO, owing to the synergistic protective effect of GO and CMC.

Preparation of Ethyl Cellulose Composite Film with Down Conversion Luminescence Properties by Doping Perovskite Quantum Dots

AbstractThe preparation and characterization of a perovskite quantum dot‐ethyl cellulose (PQD‐EC) composite film are described. The toluene suspension of perovskite quantum dots (PQDs) was injected into the ethyl cellulose (EC) toluene solution to form the transparent solution. Then the composite film was prepared by solvent casting method. The composite film had the characteristics of high optical transmittance and excellent down conversion luminescent. When excited by ultraviolet (UV) 365 nm, it exhibited bright green emission centered at 518 nm. The analyses showed that the composite film exhibited excellent thermodynamic and mechanical properties similar to the pure EC film. Further, the sandwich‐like multilayer films was prepared by encapsulating the PQDs‐EC composite film with pure EC films to overcome the defect of PQDs susceptible to water. When used as coating film for solar cell, the composite film obtained an observable enhancement in the photoelectric conversion efficiency.

Synergistic Effects of Nanocomposite Films Containing Essential Oil Nanoemulsions in Combination with Ionizing Radiation for Control of Rice Weevil Sitophilus oryzae in Stored Grains.

The fumigant toxicity of eight individual essential oils (EOs; basil, cinnamon, eucalyptus, mandarin, oregano, peppermint, tea tree, and thyme) and one binary combination (thyme and oregano) for control of the rice weevil, Sitophilus oryzae, were investigated. In bioassays, all individual and combined EOs were toxic to the rice weevil. Eucalyptus EO exhibited the highest toxicity among the individual EO treatments, causing 100% mortality at a minimum concentration of 0.8 µL/mL after 24 hr of exposure. The combination treatment of oregano and thyme EO displayed higher fumigant activity than the individual oregano or thyme treatments. A stable oil-in-water nanoemulsion was evaluated using high-pressure homogenization (microfluidization [MF]) and varying the pressure and number of cycles. The droplet size of the emulsions was found to decrease from 217 to 71 nm and encapsulation efficiency increased from 37% to 84% with increasing MF pressure and number of cycles. The optimum conditions for preparing the mixture of oregano and thyme EO nanoemulsions were evaluated to be homogenization pressure of 103 MPa and three cycles. Incorporating an oregano:thyme nanoemulsion (0.75%) into cellulose nanocrystal (CNC) containing chitosan (CH/CNC), methyl cellulose (MC/CNC), and polylactic acid (PLA/CNC) composite films resulted in extended diffusion matrices causing 32% to 51% rice weevil mortality after 14 days exposure. Irradiation at 200 Gray alone caused 79% mortality and increased to 100% when combined with the bioactive chitosan film containing the oregano:thyme nanoemulsion. PRACTICAL APPLICATION: A binary combination of oregano:thyme has potential as a biopesticide against stored product pests. The encapsulation of EO nanoemulsions into biopolymeric support could be used for bioactive packaging to prevent food spoilage and extend shelf life. Combining bioactive films with irradiation can provide complete control of rice weevil in packaged rice. The system developed in this research may also be extended to explore other food-packaging films with various food models to control different types of stored pests.

Development of bioactive composite films from chitosan and carboxymethyl cellulose using glutaraldehyde, cinnamon essential oil and oleic acid

In the present research the effect of incorporating cinnamon essential oil (CEO), oleic acid (OA) and glutaraldehyde (GL) on antimicrobial, antioxidant, mechanical, physical and morphological properties of chitosan-carboxymethyl cellulose composite films were investigated. Cross-linking effect of GL (as determined by FTIR analysis) significantly resulted in higher mechanical strength and lower water vapor permeability (WVP). Cross-linked films incorporated with CEO revealed higher and steady state antioxidant activity as well as in vitro antimicrobial properties against Listeria monocytogenes and Pseudomonas aeruginosa. Thickness, elongation at break (EAB) and WVP increased by including OA; however, water solubility significantly decreased. Color properties and microstructure of composite films were significantly affected by the additives as confirmed by SEM analyses. We showed that the antimicrobial, antioxidant, mechanical and physical properties of chitosan-carboxymethyl cellulose composite films could be improved via incorporating CEO and GL to the film matrix.

High Electromagnetic Interference Shielding Effectiveness of Carbon Nanotube–Cellulose Composite Films with Layered Structures

Inside Front Cover: In article 1800377, by Xingzhen Qin and Haisong Qi, flexible and electrically conductive carbon nanotube (CNT)-cellulose composite films are fabricated by a green route. Due to the unique layered structures of CNTs, these materials show high electromagnetic interference shielding effectiveness in the frequency range of 12–18 GHz.

High Electromagnetic Interference Shielding Effectiveness of Carbon Nanotube–Cellulose Composite Films with Layered Structures

AbstractFlexible and electrically conductive carbon nanotube (CNT)–cellulose composite films are fabricated by a green route based on sodium hydroxide/urea aqueous solution. Both single‐walled carbon nanotubes (SWCNTs) and multi‐walled carbon nanotubes (MWCNTs) are investigated as conductive fillers. The microstructure and physical properties of the films are characterized extensively. It is observed that CNTs form layered conductive networks in the cellulose matrices during the drying process. The electromagnetic interference (EMI) shielding effectiveness (SE) of these composite films is also investigated. The results exhibit that the EMI SE of the materials is in accordance with electrical conductivity, which is highly dependent on the CNT loadings. Compared to MWCNT–cellulose composite films, the films with SWCNT show more effectiveness as EMI materials in the frequency range of 12–18 GHz. With SWCNT loading of 10 wt%, the EMI SE can reach 32.5–40 dB. Considering the thickness and density of the material, furthermore, the SWCNT–cellulose film possesses an extremely high specific EMI SE value of about 7678 dB cm2 g−1, which is due to the unique layered structures of CNTs. Thus, these flexible conductive composite films have the potential to be used as high‐efficiency shielding materials against electromagnetic radiation in advanced application fields.

A promising transparent and UV-shielding composite film prepared by aramid nanofibers and nanofibrillated cellulose

An aramid nanofibers (ANFs)-functionalized nanofibrillated cellulose (NFC) composite film is effectively fabricated by the incorporation of ANFs into nanocellulose matrix. The fabrication of the composite film imitates the traditional paper-making process after homogenous mixing. The as-prepared composite film shows excellent UV-shielding performance due to the incorporation of ANFs. Thus the effect of ANFs contents is evaluated in aspects of the surface morphology, physicochemical properties including crystallinity, chemical structure and photothermal stability of composite film. Results show that the composite film with 2 wt.% of ANFs has improved mechanical properties, surface wettability compared to pure NFC film, and presents excellent UV-shielding performance ranging up to 400 nm while still retaining its high transparency. Moreover, the composite film shows high photostability even after continuous UV irradiation (365 nm) for over 12 h. The findings in the present work indicate that the ANFs-functionalized NFC composite films are promising as UV-shielding and transparent materials.

Fluorinated Carbon Nanotube/Nanofibrillated Cellulose Composite Film with Enhanced Toughness, Superior Thermal Conductivity, and Electrical Insulation.

Recently, graphene and carbon nanotubes (CNTs) promise considerable application potentials in the highly efficient thermal management of high-power devices because of their superb thermal conductivity (TC). However, the high electrical conductivity hampers their use in some fields where electrical insulating components are always required. Herein, to coordinate the thermal and electrical conductivity of CNT, fluorinated CNT (FCNT) was first used as a thermally conductive filler to prepare composite film with nanofibrillated celluloses (NFCs) via facile vacuum-assisted filtration. The obtained composite film shows a well-organized layered structure of the building blocks along the planar direction. Moreover, the one-dimensional structure of NFCs and the strong interaction of NFCs and FCNTs ensure sufficient connection between FCNT themselves and the reduced interfacial thermal resistance of NFCs/FCNTs, so that efficient heat transfer pathways can be well reserved, leading to simultaneous accessibility of high in-plane TC of 14.1 W m-1 K-1 and favorable electrical insulation property at an FCNT content of 35 wt %. Despite such a high FCNT loading, the strong interaction between NFCs and FCNTs enables the composite film to possess enhanced toughness, reliable mechanical strength, and flexibility. Therefore, we think that these outstanding comprehensive properties guarantee that the prepared composite film has promising applications in heat dissipation of next-generation portable and collapsible electronic devices.

Preparation of gelatin-based films modified with nanocrystalline cellulose

Gelatin is a natural biological macromolecule derived from the collagen in the connective tissue of the skin, bone and other tissues. It has been widely used in medicine, food and industrial production and other fields for easy molding, excellent compatibility and biodegradability. However, physical and chemical disadvantages impede its further application, seriously. Therefore, modification of the gelatin films becomes more and more important. In this study, the gelatin/nanocrystalline cellulose (NCC) composite films were prepared by casting method with 4% glycerol as plasticizer. The effect of NCC on the properties of the composite films was investigated by the characterization of its morphology and mechanical, thermal, and optical properties and water adsorption. The results showed that mechanical, thermal stability and water absorption properties of the gelatin/NCC composite film were obviously improved. The composite films showed the highest tensile strength (13.56 ± 0.25 MPa) when the mass concentration of NCC was 0.6%. Adding NCC to gelatin benefited the thermal stability of composite films. The gelatin/NCC composite film of 0.4% NCC had the highest melting transition temperature (138.9 °C). The composite films exhibited the lower water absorption (271.1%) when mass concentration of NCC was 1.0%. Thus, these results indicated that NCC could affect the properties of gelatin-based composite films, and showed it has potential for application in food packing.

In situ controllable synthesis of Ag@AgCl in cellulose film and its effect on anti-fouling properties

Cellulose–Ag@AgCl composite films were fabricated by one-step coagulation of the cellulose/1-Butyl-3-methylimidazolium chloride (BmimCl)solution with AgNO3. AgCl was firstly formed when AgNO3 was added into cellulose/BmimCl solution, and then the formed AgCl was further reacted with excess Cl−, leading to the complete dissolution of AgCl. The AgCl crystal would grow again from cellulose matrix in the air after the film formation. Meanwhile, AgCl could be partly decomposed into Ag° and formed Ag@AgCl under visible-light irradiation. The morphology of Ag@AgCl in cellulose matrix could be regulated by changing the molar ratio of BmimCl and AgNO3, the growth time of AgCl crystal and the concentration of cellulose solution. The cellulose composite film with stamen-like Ag@AgCl showed the best anti-fouling properties for methyl orange reagent under visible-light irradiation. This work also provided a simple pathway to regulate the morphology of Ag@AgCl in cellulose or other polymer matrices.