The use of nanofillers is a good strategy to improve the properties of biopolymer-basedpackaging films. The present study prepared zein-based nanocomposite film containingmontmorillonite using the solvent casting method. Mechanical, barrier, and thermal properties of the film were investigated. The x-ray diffraction patterns indicated that the composite film has an exfoliated structure.The results showed that the montmorillonite significantly improved the mechanical, barrier, and thermal properties of the zein film. The highest elongation (9.65%) and tensile strength (22.62 MPa) were obtained for the zein nanocoposites containing 0 and 10% montmorillonite, respectively. Increasing the montmorillonite content from 0% to 5% decreased the water vapor permeability of the zein film from 1.73 to 1.23 (28%). This parameter significantly increased (1.93) in film containing 10% montmorillonite. The thermal degradation temperature of zein film increased (from 353 to 373 °C) by increasing the montmorillonite content from 0% to 10%. The results revealed that a small amount of montmorillonite can improve the mechanical and barrier properties of zein film, although uniform dispersion ofmontmorillonite in the zein network is essential to improving the properties of the film.Keyword:

Sustainable biological and inorganic nanomaterials such as montmorillonite have been the focus of researchers due to their properties such as biocompatibility and biodegradability for producing various products. This research investigated the effect of coating paper coated with carboxymethyl cellulose and montmorillonite and their combination on resistance properties and optical properties. For this purpose, coating materials with specific conditions of carboxymethyl cellulose and Montmorillonite (3, 5, and 7%) were applied on the papers. Also, the papers were studied by scanning electron microscope. The results of the tests showed that the resistance characteristics (tensile, burst, and tear resistance index) of the coated papers increased by adding the percentage of montmorillonite. The combination of carboxymethyl cellulose and 7% montmorillonite has the best resistance characteristics compared to paper. The brightness characteristic increased by adding montmorillonite, but the opacity did not change significantly. Also, the colorimetry was improved by adding montmorillonite up to 5% but the 7% sample decreased. In addition, the examination of the microscopic images showed that the montmorillonite fills the pores on the surface of the paper significantly compared to the control paper.

Glutaraldehyde (G) is used in cross-linking. Silica clays, like montmorillonite (MMT), enhance the mechanical strength of polymeric nano-composites. The aim of the present study was to determine the effects of G and MMT content on physicochemical properties of alendronate loaded agar/MMT/xanthan nano-composite scaffolds which are useful in regenerating bones in osteoporosis and other defects caused by trauma. Thirteen different formulations were designed by a three-level factorial design. The effects of two variables, i.e. G and MMT content, on drug loading, release efficiency percentage, swelling, and biodegradation of nano-composites were studied. The morphology of the optimized scaffold and its capability to grow the mesenchymal cells were evaluated by scanning electron microscopy (SEM) and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, respectively. Changing the concentration of G and MMT had no significant effects on drug loading in scaffolds. Unlike MMT, increasing the concentration of G increased drug release. Increasing the concentration of both studied variables decreased the swelling and biodegradation of the nano-composites. The scaffolds significantly enhanced the growth of mesenchymal cells. The optimum concentrations of MMT and G for preparing three dimensional scaffolds of agar/MMT/xanthan were 3% and 1%, respectively. These concentrations caused significant growth of mesenchymal cells.

Starch-based active packaging which contain additives has been used to food preservation, significantly. Organic nano-clays such as montmorillonite cause to strength of these films and additives such as antioxidants reduces food spoilage rate. In this study starch-based films with different percentages of montmorillonite from 0 to 8% and the green tea extract from 0 to 2.5 % were produced by casting method and physical properties of the films such as tensile strength, water absorption, water vapor permeability and solubility were investigated. Then flax seed oil was packaged in these films and some chemical properties of oil, peroxide index and acidity, were evaluated. Then the optimal point in the film production was determined with Minitab 17 software by response surface methodology. The results showed that low content of both independent factors caused to decrease of water absorption and solubility and addition of montmorillonite and green tea extract increased the tensile strength of films. It was seen in medium content of both factor water vapor permeability of films was the least. Montmorillonite in high and medium content caused to reduction of peroxide index and acidity, respectively. Organoleptic tests showed that edible films did not change the odor, flavor, color and overall acceptance of flax seed oil, too. The optimal point to justify was in 2.42% of Montmorillonite and 0.181% of green tea extract caused to increase shelf life of flax seed oil to 7 days.

Starch-based active packaging which contain additives has been used to food preservation, significantly. Organic nano-clays such as montmorillonite cause to strength of these films and additives such as antioxidants reduces food spoilage rate. In this study starch-based films with different percentages of montmorillonite from 0 to 8% and the green tea extract from 0 to 2.5 % were produced by casting method and physical properties of the films such as tensile strength, water absorption, water vapor permeability and solubility were investigated. Then flax seed oil was packaged in these films and some chemical properties of oil, peroxide index and acidity, were evaluated. Then the optimal point in the film production was determined with Minitab 17 software by response surface methodology. The results showed that low content of both independent factors caused to decrease of water absorption and solubility and addition of montmorillonite and green tea extract increased the tensile strength of films. It was seen in medium content of both factor water vapor permeability of films was the least. Montmorillonite in high and medium content caused to reduction of peroxide index and acidity, respectively. Organoleptic tests showed that edible films did not change the odor, flavor, color and overall acceptance of flax seed oil, too. The optimal point to justify was in 2.42% of Montmorillonite and 0.181% of green tea extract caused to increase shelf life of flax seed oil to 7 days.

Kefiran is an exopolysaccharide produced by microorganisms present in the kefir grains that has several health promoting properties. In this research, physico-mechanical and thermal characteristics of nanocomposite film composed of kefiran-montmorillonite (MMT; 1, 3 and 5% w/w) were studied. Results showed that the thickness and the tensile strength of the films increased by increasing the nanoclay content but its effect on the elongation at break, glass transition temperature and melting temperature in various concentrations is different, so that these factors increase until concentration of 3% of the nanoclay and decrease in higher concentrations(5%). X-ray diffraction analysis showed that formation of an exfoliated structure with the addition of small amounts of MMT to the kefiran matrix. Scanning electron microscopy and the surface topography results showed ideal dispersion for MMT nanoparticles into the structure of the bio-nanocomposite films and a considerable increase in roughness parameters by incorporating the nanoparticles in kefiran matrix,respectively.

In this research, adsorption of six tri-bisphenol-A-diglycidyl ether oligomers on montmorillonite are investigated using molecular dynamics simulation method at  298, 323, and 348k. At the beginning of the simulation, the distance between oligomers and Montmorillonite is set greater than cut-off distance; but, the distance between oligomer chains is smaller than the cut-off distance. During the simulation, the oligomer chains are adsorbed on the surface and after temperature and pressure equilibration, sampling is done for data analysis. The results show that the adsorption of oligomer chains on Montmorillonite is done via etheric Oxygens of oligomer chains. The etheric oxygen has a partial negative charge and reacts sufficiently with positive calcium ions of Montmorillonite. The result of this interaction is the strong adsorption of oligomer chains on Montmorillonite. Increasing temperature causes an increase in distance between adsorbed oligomer chains, but, does not strong effect on adsorption of chains on surface.

Nano technology makes the possibility to achieve specific properties for materials. In this process, by reducing the size of materials in the range of nano size, new noticeable behaviour for material can be observed. Such behaviour cannot be observed for larger particles from that material. Bentonite soils contain more than 76% montmorillonite and some other minerals. Pure montmorillonite with nano size has a vast industrial application in which its production is relatively costly and time consuming.  This research is aimed to propose a method for segregation of bentonite components to reach nano montmorillonite. To achieve this objective, a mechanical method is proposed. Based on this method, a nano montmorillonite with micro and nano size is achieved. The segregation process is monitored with PSA, XRD, SSA and SEM experiments. The results of this research show that a nano montmorillonite with SSA of 522.58 m2/g and average diameter of 6.13 micron is attained. The achieved nano montmorillonite has larger purity in comparison to Cloisite Na+. In addition, it has lower average particle size than Cloisite Na+.  Furthermore, according to the results of this research the extracted nano clay is free from carbonate and quartz particles. The SSA of this nano montmorillonite was 25% more than that of bentonite. The proposed method is relatively inexpensive. Moreover, since no chemical is used in its production process, it is a suitable sample for practical, research, and industrial projects.