In this paper, for the first time, it is studied the synergetic properties of two different grades of nanocelluloses with different chemical compositions (cellulose nanofibrils-CNF with less than 1% ...of lignin and lignocellulose nanofibrils-LCNF with 16% of lignin). CNF and LCNF were mixed in different ratios to obtain bi-component films. Their performance in terms of transparency, bioactivity, thermo-mechanical and gas barrier properties was evaluated and compared with the performance of the neat CNF films. The presence of LCNF in the formulations conferred antioxidant and UV blocking properties to the films, as well as improved mechanical and barrier properties. Specifically, the incorporation of 25% LCNF to the CNF films increased the mechanical properties (94% increase in tensile stress and a 414% increase in strain at break) and decreased the water vapor transmission rate by 16% and the oxygen transmission rate by 53%. This performance improvement was attributed to the coexistence of nanocelluloses with different chemical composition and morphology. LCNF contributed to increment the interfacial adhesion between cellulose nanofibrils due to the presence of lignin and promote the creation of more tortuous paths for gas molecules. These synergetic properties shown by the CNF/LCNF bi-component films demonstrate high potential to be used as gas barrier packaging solutions.
•CNF and LCNF from residual biomass are used to produce bicomponent nanocellulose films.•LCNF conferred UV-blocking and antioxidant properties to the films.•LCNF presence improved flexibility and tensile strength of CNF films.•All developed bicomponent films display better gas barrier properties than CNF films.•CNF/LCNF formulations have higher potential to be used as barrier coatings/films than CNF.
This review article was prompted by a remarkable growth in the number of scientific publications dealing with the use of nanocellulose (especially nanofibrillated cellulose (NFC), cellulose ...nanocrystals (CNC), and bacterial cellulose (BC)) to enhance the barrier properties and other performance attributes of new generations of packaging products. Recent research has confirmed and extended what is known about oxygen barrier and water vapor transmission performance, strength properties, and the susceptibility of nanocellulose-based films and coatings to the presence of humidity or moisture. Recent research also points to various promising strategies to prepare ecologically-friendly packaging materials, taking advantage of nanocellulose-based layers, to compete in an arena that has long been dominated by synthetic plastics. Some promising approaches entail usage of multiple layers of different materials or additives such as waxes, high-aspect ratio nano-clays, and surface-active compounds in addition to the nanocellulose material. While various high-end applications may be achieved by chemical derivatization or grafting of the nanocellulose, the current trends in research suggest that high-volume implementation will likely incorporate water-based formulations, which may include water-based dispersions or emulsions, depending on the end-uses.
Herein, we present the fabrication of dispersed, 5.0 wt % (1.74 vol %) Ti3C2T z MXene epoxy nanocomposites (NCs), and report on their water transport and mechanical properties. To make the ...composites, Li+ ions between Ti3C2T z MXene multilayers, MLs, present after the etching step were exchanged with either 12-aminolauric acid, ALA, or di(hydrogenated tallow)benzyl methyl ammonium chloride, DHT. After drying, the resulting ML powders were added at room temperature to the epoxy resin (diglycidyl ether of bisphenol A), followed by the curing agent, triethylenetetramine. The NCs were characterized by X-ray diffraction, thermogravimetric analysis, dynamic vapor sorption, dynamic mechanical analysis, scanning and transmission electron microscopies, and infrared spectroscopy. From XRD, the lack of signature MXene basal peaks, as well as evidence of exfoliation supported by TEM micrographs, we conclude that the MXene ML had indeed been intercalated by the epoxy. The distribution of the exfoliated multilayers, MLs, however, was not uniform. Nevertheless, our relative permeabilities, with a 1.74 vol % loading, are 5 times lower than results obtained in the carbon- or clay-reinforced epoxy NC literature. The lower permeabilities are due to reductions in both solubilities and diffusivities relative to the neat polymer. In the case of DHT, the water solubility at all temperatures was almost halved. The mechanical properties and thermal stability are found to be slightly improved with the addition of DHT-MXene. As far as we are aware, this is the first report of exfoliation of MXene in an epoxy matrix. Additionally, this study is the first to measure the diffusion of water in MXene epoxy NCs. More work on better dispersion of the MLs is indicated and ongoing.
Hot compression molding was utilized to develop composite films from cassava starch (CS) and xanthan gum (XG). The addition of XG significantly reduces the hardness, loss angle, and gelatinization ...enthalpy of the film-forming materials, thereby lowering the difficulty of gelatinization. Without the addition of XG, cassava starch particles cannot fully gelatinize at the selected processing temperature. X-ray diffraction analysis revealed a significant enhancement in the gelatinization of starch after the addition of XG. Additionally, images from scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) demonstrate that the addition of XG promotes the formation of a more continuous and uniform film matrix. Film processability was assessed through thickness and optical, mechanical, and barrier properties. Upon XG addition, the thickness decreased from 1.86 mm to 0.08 mm, and the color difference decreased from 40.18 to 6.04. Compared to pure cassava starch film, XG addition decreased water vapor permeability and oxygen permeability while improving tensile strength and brightness. The optimum performance was observed with 4 % XG, where the elongation at the break was 31.22 % and the tensile strength was 14.15 MPa. This study confirmed the potential application value of XG in promoting starch gelatinization and improving the properties of composite film in the process of preparing starch film by hot compression.
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•TCS/XG films have improved barrier and mechanical properties.•XG promoted the gelatinization of cassava starch in TCS/XG films.•The addition of XG facilitated the formation of a continuous and uniform film matrix.•XG significantly improved the structural continuity and compressibility of the film-forming compounds.
Polyvinyl alcohol (PVA) is used in many applications because of its excellent physicochemical properties, non-toxicity, and biodegradability. However, its relatively low water resistance, poor water ...vapor/ultraviolet (UV) barrier properties, and poor mechanical properties compared with conventional polymers limit its applications in food packaging. In this study, cellulose nanocrystals (CNCs) and alkyl ketene dimer (AKD) were used to overcome these issues. The mechanical properties, water resistance, and barrier properties of the developed PVA/CNC/AKD films were significantly improved relative to those of a neat PVA film. The mechanical strength of a PVA/CNC/AKD 15% film (15 wt% AKD in a PVA/CNC matrix of 5 wt% CNCs) was 64.6% and 37% higher than those of PVA and PVA/CNC films, respectively. The water vapor transmission rate, water absorption, and solubility of PVA/CNC/AKD 15% were 41.2%, 61.1%, and 92.9%, respectively (lower than those of the neat PVA film). In addition, the UV barrier properties and soil degradation of the PVA/CNC/AKD films were significantly improved.
•Cost-effective, ecofriendly chemicals AKD and CNCs were used to modify a PVA film.•Mechanical strength of PVA/CNC/AKD was 1.64 times higher than the PVA film.•Water absorption and solubility of PVA/CNC/AKD films were significantly reduced compared with those of the PVA film.•The PVA/CNC/AKD film exhibited excellent water vapor and UV barrier properties.•Adding CNCs and AKD increased the biodegradation rate of PVA.
Attenuating the moisture sensitivity of hydrophilic protein/polysaccharide-based films without impairing other properties remains a challenge. Fatty acid dispersed in Pickering emulsion was proposed ...to overcome such issue. An increase in fatty acid chain length slightly reduced the water vapor permeability (WVP) of emulsion films. As the number of fatty acid double bonds increased from 0 to 1, the WVP of emulsion films was significantly decreased by 14.02% while mechanical properties were significantly enhanced. More hydrogen bonds and stronger electrostatic interactions in the presence of fatty acids were observed by molecular dynamics simulation. The weight loss of bananas coated with oleic acid-incorporated film-forming emulsion was 6.81% lower than that of uncoated group after 4 days, and the corresponding film was more effective to delay oil oxidation than the commercial polypropylene film, indicating that the film is a promising alternative to food coating and packaging material.
•Pickering emulsion containing oleic acid performed superior physical stability.•Emulsion film with oleic acid (EF-C18:1) showed the best moisture barrier properties.•EF-C18:1 exhibited a relatively continuous and dense structure.•Introducing fatty acid enhanced the hydrogen bonding and electrostatic interactions.•EF-C18:1 provided effective protection against banana spoilage and oil oxidation.
Currently, petroleum-based synthetic plastics are used as a key barrier material in the paper-based packaging of several food and nonfood goods. This widespread usage of plastic as a barrier lining ...is not only harmful to human and marine health, but it is also polluting the ecosystem. Researchers and food manufacturers are focused on biobased alternatives because of its numerous advantages, including biodegradability, biocompatibility, non-toxicity, and structural flexibility. When used alone or in composites/multilayers, these biobased alternatives provide strong barrier qualities against grease, oxygen, microbes, air, and water. According to the most recent literature reports, biobased polymers for barrier coatings are having difficulty breaking into the business. Technological breakthroughs in the field of bioplastic production and application are rapidly evolving, proffering new options for academics and industry to collaborate and develop sustainable packaging solutions. Existing techniques, such as multilayer coating of nanocomposites, can be improved further by designing them in a more systematic manner to attain the best barrier qualities. Modified nanocellulose, lignin nanoparticles, and bio-polyester are among the most promising future candidates for nanocomposite-based packaging films with high barrier qualities. In this review, the state-of-art and research advancements made in biobased polymeric alternatives such as paper and board barrier coating are summarized. Finally, the existing limitations and potential future development prospects for these biobased polymers as barrier materials are reviewed.
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•Food packaging pays a key role in food safety and food quality.•Fossil based barrier coatings are causing serious environmental and health problems.•Biobased polymers can replace petroleum-based barrier ingredients.•The barrier properties of bioplastics need to be enhanced to make it applicable on industrial scale.•Cellulose, Chitosan, and bio polyesters are among the strong candidates for green packaging.
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•S-GO hybrids were prepared by in situ growth of sulfur on the surface of GO sheets.•S-GO hybrids crosslinked SBR molecules and dispersed uniformly in SBR matrix.•Strong chemical ...interfaces were constructed between S-GO and SBR molecules.•S-GO/SBR composites exhibit unique gas barrier properties and mechanical strength.
Constructing strong interfacial interactions and complex filler networks is crucial to establishing high gas barrier properties in rubber composites. In this research, sulfur-graphene oxide (S-GO) hybrids were prepared by in situ growth of sulfur on the surfaces of GO sheets. The S-GO hybrids were also introduced into butadiene styrene rubber (SBR) using a green method of latex compounding. Results showed that sulfur could melt and spread on the surface of the GO during the crosslinking process at high temperatures. This process prevented the aggregation of GO and resulted in a fine dispersion of GO and complex filler networks in S-GO/SBR composites. More importantly, the sulfur particles on the GO surface not only aided the crosslinking of rubber molecules, but also chemically reacted with the GO radicals generated at high temperatures. This occurred by the homolytic cleavage of oxygen-containing groups, which thereby constructed covalent interfaces between the GO and SBR molecules. Due to these strong interfaces and complex filler networks, the tensile and tear strength of S-GO/SBR composites increased by 66.2% and 26.6%, respectively, when compared with conventional GO/SBR composites. The gas permeability coefficient of S-GO/SBR composites was decreased dramatically by 50.7% and 23.3% by comparison with that of pure SBR and GO/SBR composites, respectively. The apparent improvement demonstrated that the facile and effective method used in this research may open up new opportunities for the development of multifunctional rubber crosslinking agent as well as the fabrication of rubber composites with high performance.
•Polymers used for packaging such as chitosan, starch, polylactic acid, polyvinyl alcohol and poly caprolactone.•The most favorable nanomaterials are nanoclays, zinc oxide, titanium dioxide and ...silver nanoparticles.•The barrier properties of prepared packaging films against oxygen, carbon dioxide water vapor should be improved.•The mechanical, thermal stability and antibacterial activity of the packaging films should be enhanced.
Bionanocomposites materials open a chance for the usage of novel, high performance, lightweight, and ecofriendly composite materials making them take place the traditional non-biodegradable plastic packaging materials. Biopolymers like polysaccharides such as chitosan (CS), carboxymethyl cellulose (CMC), starch and cellophane could be used to resolve environmental hazards owing to their biodegradability and non-toxicity. In addition these advantages, polysaccharides have some disadvantages for example poor mechanical properties and low resistance to water. Therefore, nanomaterials are used to improve the thermal, mechanical and gas barrier properties without hindering their biodegradable and non-toxic characters. Furthermore, the most favorable nanomaterials are layered silicate nanoclays for example montmorillonite (MMT) and kaolinite, zinc oxide (ZnO-NPs), titanium dioxide (TiO2-NPs), and silver nanoparticles (Ag-NPs). In packaging application, the improvement of barrier properties of prepared films against oxygen, carbon dioxide, flavor compounds diffusion through the packaging films. Wide varieties of nanomaterials are suitable to offer smart and/or intelligent properties for food packaging materials, as demonstrated by oxygen scavenging capability, antimicrobial activity, and sign of the level of exposure to various harmful features for instance oxygen levels or insufficient temperatures. The compatibility between nanomaterials and polymers matrix consider the most challenge for the preparation of bionanocomposites as well as getting whole distribution of nanoparticles into the polymer matrix. We keen in this review the development of packaging materials performance and their mechanical, degradability and thermal stability as well as antibacterial activity for utilization of bionanocomposites in different packaging application is considered.
Consumption of fruits and vegetables, that are rich in antioxidant vitamins and polyphenols, can decrease the risk of the development of age-related chronic diseases. A gradual decline in moisture, ...sensory properties, vitamin C and polyphenols contents was observed during fruits and vegetables storage.
The recent studies on the effect of chitosan-based coatings on the changes of nutritional quality of fruits and vegetables during postharvest storage have been summarized in this review. The latest data of the application of chitosan-based coatings for prevention of the decrease in contents of natural antioxidants ascorbic acid, anthocyanins, and total polyphenols in various fruits and vegetables during postharvest storage have been reviewed. The mechanisms of action and the role of polyphenols and vitamin C in prevention of age-related diseases has been also discussed.
Barrier and mechanical properties of chitosan-based films and coatings can be improved by the development of nanocomposite chitosan films and coatings incorporating also rosemary, sunflower, lavender, olive, and carp oils. Layer-by-layer self assembly can be used in the formation of multinanolayer edible coatings.
•Chitosan-based edible coatings decrease vitamin C losses in fruits during storage.•Chitosan-based edible coatings decrease polyphenols losses in fruits during storage.•LbL self assembly can be used in the formation of multilayer fruit edible coatings.•Composite chitosan nanocoatings can essentially decrease water vapor permeability.
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