جستجوی مقالات مرتبط با کلیدواژه « نانوکامپوزیت » در نشریات گروه « صنایع غذایی »

The aim of this study was optimization and improvement of the physic-chemical characteristics films based on basil seed mucilage (BSM) and carboxymethyl cellulose (CMC) (100, 162.5 and 225% w/w the mucilage) using montmorillonite (MMT) (0 and 8% w/w the mucilage) by casting method. The produced films properties were evaluated for thickness, moisture content, density, mechanical properties, Fourier Transform Infrared Spectrometer (FTIR), and thermogravimetric analysis (TGA). Results indicated that thickness and density of the films were not significantly influenced by CMC and MMT addition (p>0.05), but the moisture content of nanocomposites decreased with increasing CMC content (p<0.05). Presence of CMC and MMT in the film matrix caused to enhancement of ultimate tensile strength (UTS) and elongation at break (EB) in nanocomposites; the maximum of UTS and EB with the values of 27.9 MPa and 41%, respectively, were obtained for the nanocomposite made by 225% CMC and 8% MMT. FTIR spectra revealed no new compounds resultant from the chemical interactions, and only some shifts were observed for some peaks, and also slightly weakening or intensifying in several peaks. TGA plots showed that incorporation of CMC and MMT led to improvement of thermal properties. In conclusion, simultaneous loading of nanoclay and CMC generated the improved nanocomposites, and the treatment loaded with both MMT and the maximum level of CMC (T7) is advised as the best film for employing in the food packaging.

Green synthesis plays an important role because of its involvement in unusual syntheses of metal nanoparticles from plant extracts, which have antimicrobial potential. Therefore, green synthesis of nanoparticles from plant extracts is a suitable way to produce nanoparticles. Therefore, the aim of this research was to synthesize Ag/AgCl /TiO2 three-component nanocomposite using Zataria Multiflora plant and evaluate the size and morphology of the produced nanoparticles. For this purpose, synthesis, and characterization of Ag/AgCl/TiO2, a three-component nanocomposite was done using Zataria Multiflora plant extract using UV-Vis, XRD, TEM, and FTIR techniques. Then, the characteristics of nanocomposites were investigated. The results showed that the largest diameter of the non-growth halo was observed in all studied bacteria in the nanocomposite containing 50% color and in the nanocomposite containing 5% (Ag/TiO2mol). The diameter of the non-growth halo increased from 0.5% to 3% in the film containing TiO2/Ag/AgCl nanoparticles in all investigated microorganisms. Also, TEM images showed the uniform loading of Ag/AgCl nanoparticles on the TiO2 surface. Overall, the obtained results showed that Zataria Multiflora plant extract, along with silver and titanium dioxide nanocomposites, has a high potential in producing nanoparticles with high purity, in nanometer sizes, with antimicrobial properties, which has properties in the food industry as a coating and film.

In this study, the effect of nanoparticles on oxide at three levels of 1, 3 and 5% was added to polylactic acid and chitosan nanocomposites and the results of its SEM (electron microscope) evaluation were evaluated and showed films containing polylactic acid and chitosan. It had an irregular and compact structure and with the addition of nanoparticles on oxide, it had a regular and cohesive structure. And water vapor permeability showed a significant effect (P <0.05). The results of histometry showed that with increasing the concentration of nanoparticles, the tensile strength of the film and the nanocomposite coating was significantly lower than the control treatment (P <0.05). Also, large changes in length to break point did not show a statistically significant difference. The results of tissue stiffness of this study also showed that during the 15-day storage time, the test treatment had the highest amount of stiffness. The effect of film and coating of nanocomposites based on polylactic acid and chitosan containing nanoparticles on zinc oxide on microbial properties indicated that during the shelf life of bread containing polylactic acid and chitosan dimers has an inhibitory effect on fungal growth by increasing nanoparticles on zinc oxide. Increases significantly. It also showed that the shelf life of seven sliced ​​toast containing the mentioned variables was higher at 5% level compared to the control treatment.

In this study, biodegradable film was prepared from polyvinyl alcohol. Silver chloride nanoparticles and spirulina algae powder were used to modify the physicochemical structure and create antioxidant activity in the film. The surface morphology of the film was investigated. Polyvinyl alcohol film and its composites were used for packaging virgin olive oil. D-optimal design was used to investigate the effect of packaging type and storage time on the chemical, color and sensory characteristics of the oil. Chemical characteristics (acidity, peroxide value, refractive index and total phenol), sensory and color characteristics were investigated. The response surface method was used to investigate the effect of independent variables on the oil as well as the created mathematical models. The obtained results showed that in polyvinyl alcohol film modified with silver chloride particles and polyvinyl alcohol modified with silver chloride and spirulina particles, the presence of these particles on the surface of the film was completely evident. The results of the chemical, sensory and color analysis of the oil showed that the chemical, sensory and color quality of the oil decreased with the increase in the storage time of the oil in all packages. Peroxide value as the most important indicator of the quality of oils in normal packaging increased from 1 to 7 (mEq O2/Kg oil) during 30 days of storage, while in oil packaged with polyvinyl alcohol modified with silver chloride and spirulina algae, this increase was from 1 to 2 (mEq O2/Kg oil). In general, oils packaged with polyvinyl alcohol modified with silver chloride and spirulina algae showed the least quality changes compared to normal packaging, which indicates the ability of these films to control the quality and increase the shelf life of virgin olive oil.

In this study, the effect of selected optimal film samples based on apple pectin and mung bean protein containing microencapsulation of cardamom extract, cerium oxide nanoparticles and quantum dot nanoparticles on the packaging of refined cheese was studied and physicochemical properties of cheese including acidity, pH, salt content, moisture content Lipolysis, proteolysis, fat and sensory evaluation were evaluated over time (0-60 days) and optimal film according to I-Optimal design. Based on the results, the effect of different optimally selected films on cheese packaging was non-significant; while the passage of time had a significant effect on the evaluated characteristics. According to the results, over time, the pH, moisture, proteolysis, fat and overall acceptance of samples of packaged ultra-refined cheese decreased significantly. In addition, the effect of optimal film packaging on ultra-refined cheese increased acidity, salt and lipolysis. The results of sensory evaluation showed that the evaluators' score on the acceptance of cheese samples decreased significantly over time. In general, nanocomposite films based on pectin and mung bean protein with cerium oxide and carbon quantum dot nanoparticles and microencapsulation of cardamom extract can be used in the packaging of refined cheese.

The most important application of nanotechnology in the food industry is the production of active packaging with antimicrobial properties, packaging with special mechanical properties in terms of gas and heat exchange and nanosensors in intelligent packaging. The aim of this study was to investigate the antimicrobial effect of silver and copper nanocomposites on Escherichia coli and Staphylococcus aureus. Nanocomposites containing silver and copper nanoparticles in 1, 3, 5 and 7% percentages were produced by extrusion method and were subjected to nanometric analysis. Then, the antimicrobial test of nanocomposites was performed on commercial strains of Staphylococcus aureus and Escherichia coli by measuring the inhibition of growth in the culture medium.  The data showed that the size of copper and silver nanoparticles was in the range of 20 to 50 nm and the dispersion of nanoparticles on the surface of nanocomposites was uniform with high purity. Antimicrobial test of nanocomposites showed that with increasing the percentage of nanoparticles, the diameter of the growth inhibition of nanocomposites increased significantly and the rate of inhibition of growth of silver nanoparticles was higher than copper (p≤0.05).  Staphylococcus aureus was more sensitive to copper and silver nanoparticles than Escherichia coli (p≤0.05). The results of the present study showed that silver and copper nanocomposites with high antimicrobial properties can be used for food packaging.

Due to the fact that the use of biodegradable films helps to protect the environment, in this study, the physical, mechanical, antioxidant and thermal properties of polylactic acid films containing polypyrrole, ‌ polyaniline and copper oxide were investigated. The results showed that due to the addition of oxidant nanoparticles, the thickness of the films increased and their water vapor permeability decreased significantly. The solubility of the films also decreased significantly with increasing the amount of copper oxide nanoparticles. The resulting films showed less flexibility due to the addition of polyaniline and polypyrrole, while their resistance to failure showed a relative increase. Antioxidant activity of polylactic acid films containing polypyrrole / CuO and polyaniline / CuO showed a significant increase compared to pure polylactic acid (p<0.05). Pure polylactic acid film did not show any electrical conductivity, If the addition of polypyrrole and polyaniline increased the electrical conductivity of the films, the copper oxide nanoparticles also had no significant effect on the electrical conductivity. These films can be used as biosensors in food packaging due to their conductivity and suitable thermal, mechanical and water vapor permeability properties.

Chitosan based films have several disadvantages, such as poor mechanical properties and low moisture deterioration, which limits their use in food packaging. In this study, nanomaterials such as nanoclay (M) and nanosilver (Ag) were used to improve the properties of the film whilst applying electrical current during film drying. Nanocomposite films based on chitosan, were prepared by adding four levels 0, 1, 3 and 5% silver and clay, then heat and electricity with 0, 15, 30 and 60 Voltage were simultaneously applied to dry them, finally their characteristics like including WVP, O2P, physical and mechanical properties, and microstructure were studied. The presence of nanoparticles in nanocomposite films increased the moisture, thickness, opacity, WVP, O2P and improved mechanical properties, incomparison with pure chitosan film. On the other hand, the concentration of 3% in both treatments improve the permeability and mechanical properties of the 1 and 5% levels. The application of electrical current had no significant effect on moisture content, solubility and thickness. In contrast, the use of electric current with a voltage of 30, improved mechanical properties, turbidity and WVP and a voltage of 60, improved O2P in nanocomposites. The images produced by the SEM show that the pure chitosan film has a rough surface and multiple gaps and the film surface of the nanoclay is relatively smooth and compact, which allows for increased tensile strength and inhibitory properties. The film containing nanosilver also had a more turbulent structure with a gap, turbidity and mechanical properties, and less inhibitory properties than nanoclay.

Biodegradable polymers have supplied most of common packaging materials because they present several desired features. The purpose of this study was to prepare and investigate the physicochemical properties of carboxymethyl cellulose based nanocomposite film containing inulin with three different concentrations (0, 10 and 20%) and cellulose nanofiber in three levels (0, 2.5 and 5%). Thickness, Water vapor permeability (WVP), Water contact angle, mechanical properties, field emission scanning electron microscopy (FE-SEM) and X-ray diffraction were evaluated for film samples. WVP decreased with adding cellulose nanofiber and inulin and water contact angle increased significantly (p <0.05). The mechanical properties were also improved by adding the cellulose nanofibers. Whereas inulin had a negative effect on mechanical properties by decreasing tensile strength (UTS) and increasing elongation to break (ETB), this effect of inulin was compensated by cellulose nanofiber in the composite films containing inulin and cellulose nanofiber. The FE-SEM and X-ray diffraction results showed that the cellulose nanofiber and inulin were dispersed in the polymeric matrix and formed a dense and compact structure in compared to the control film. Results showed that cellulose nanofiber and inulin improve the properties of carboxymethyl cellulose based nanocomposites and the obtained film can be used as a new choice in food packaging.

In this research, carboxymethyl cellulose (CMC)-based nanocomposite films containing montmorillonite (MMT) (1, 3 and 5% wt) were fabricated via casting method.Then, hybrid nanocomposites were prepared by loading dioxide titanium (TiO2) (1, 3 and 5% wt) nanoparticles (NPs) into nanocomposites containing 5% MMT. Moisture content, density, moisture uptake and mechanical properties of the produced films were determined. Also, surface morphology of the nanocompositeswere measured by scanning electron microscopy (SEM).The obtained results indicated that addition of NPs resulted in slightly increase of the films moisture content, and the production of denser samples. Incorporation of 5% MMT decreased moisture uptake of the nanocomposites up to 30%; this decreasing trend was maintained with TiO2 loading. The nanoclays enhanced ultimate tensile strength (UTS) and Young's modulus (YM) of the films at the expense of elongation at break. Addition of TiO2 into MMT-loaded nanocomposites caused to structural weakening and diminishing UTS and YM. SEM micrographs showed well-dispersed MMT and TiO2NPs through the films surface especially at low concentrations. In conclusion, although the films loaded with nanoclays exhibited better properties than the control film, inclusion of TiO2 improved the functional characteristics of them and extended the potential as a biodegradable packaging.

Due to increasing attention to the environment, as well as consumer demand for healthy, nutritive food products and extended shelf life, in the recent years, the food and packaging industries have paid increasing attention to biodegradable edible packaging prepared from biopolymers such as proteins, polysaccharides, and lipids or their combinations. These biodegradable films may act as carrier of wide variety of additives, such as antimicrobial, antioxidant agents, flavors, colorants and spices which improve the functionality of the packaging materials by addition of novel or extra functions. In the present study, an antioxidant/antimicrobial active packaging based on chitosan biopolymer was designed. For this purpose, lignocellulose nanofibers (LCNF) and cellulose nanofibers (CNF) at concentration of 4% were used as reinforcement of biopolymer properties, as well as to control the release of Origanum vulgare subsp. gracile and Carum copticum essential oils (as antioxidant/antimicrobial agent) from the packaging material into the foodstuff. The O. vulgare ssp. gracile leaves and C. copticum seeds were obtained from wild plants in mountains of Urmia (Iran). LCNF (average diameter about 55 nm, average length about 2–5 μm, 99% purity) produced from unbleached hardwood pulp through mechanical and acid treatments and CNF (average diameter about 28 nm, average length about 2–3 μm, 99% purity) prepared from softwoods through mechanical disintegration were kindly provided by Nano Novin Polymer Co. (Saari, Iran). Chitosan (medium molecular weight, from shrimp shell with a deacetylation degree of 75–85%), purchased from Sigma-Aldrich (St. Louis, MO, USA). Chitosan based bionanocomposite films incorporated with organic nanofillers and essential oils were developed by solvent casting method. The synthesized films were characterized by XRD and DSC analyses. To determine the prepared films would have potential to be used as an active packaging, water vapor permeability, water solubility, color, transparency, mechanical properties, antimicrobial and antioxidant activity of the films were also evaluated. In order to determine the efficiency of activated nanocomposites, the effect of these films was evaluated on the oxidative stability of rapeseed oil without antioxidants and compared with the effect of TBHQ synthetic antioxidant. The results showed that the addition of essential oils did not have a significant effect on the crystallinity and thermal properties of the films, while organic reinforcement increased the crystalline properties and thermal resistance of nanocomposite films. By applying the essential oils and CNF and LCNF in the structure of the films, the apparent transparency and consequently the amount of light passage from them decreased compared to the control sample. With addition of essential oils separately and in combination, as well as CNF and LCNF in the structure of films, solubility and film permeability decreased compared to pure chitosan film. By adding of two essential oils with a ratio of 50:50, tensile strength (UTS) and strain to break (STB) of films were increased, while organic nanofibers led to an increase in UTS and a significant reduction in STB of nanocomposites. It was also found that active films containing different ratios of essential oil had remarkable antioxidant activity and high antimicrobial activity against E.coli and B.cereus bacteria, which by adding CNF and LCNF these features were reduced due to the role of controlling the release of essential oil compounds by nanofibers. With the numerical optimization of the software, the optimal amount for the essential oils of C. copticum and O. vulgare oils were 2.29 and 2.71% (5% mix) respectively, in combination with the LCNF nanofibers. The results of oxidative stability of Canola oil showed that nanocomposites containing 5% essential oil were considerably able to keep the oil freshness during storage at ambient temperature and delay the oxidation of the oil.

Polystyrene nanocomposites were prepared with varying amounts of nanotitanium dioxide and nanosilver by melt mixing process at 190°C. The nanocomposites structure was characterised by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The mechanical properties were obtained with tensile test. The influence of nanoparticles on the thermal properties of polystyrene matrix was examined using differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). The results of the SEM showed that both nanoparticles were present in nanocomposite, and the distribution of nanoparticles in the polymer was relatively good, despite the fact that in some places aggregation (with maximum size of 55 nm) were observed. The EDS spectrum showed that the nanocomposite was non-impure and contained three elements of carbon, titanium and silver, and the amount of nanotitanium was about 10 times that of silver. The augment of nanoparticles leading to decrease Young’s modules and stress at break point slightly. But, a point of view yield at break had not seen significantly different (P˃0.05). The investigating of the thermal properties of the samplesshowed they did not differ significantly from the point of view of glass temperature and thermal stability of the polystyrene and nanocomposites.

Biopolymer-based films such as chitosan have been studied widely due to their biodegradability and biocompatibility. Chitosan has a great potential for a wide range of food applications but its’ hydrophilic character, and consequently its poor mechanical properties in the moist condition, limits its application (1, 2). Composite films have received much attention, because of their extraordinary possibility to improve the properties of films. One of the promising ways to modify biopolymer properties in terms of physicomechanical properties, inherent water sensitivity, and their relatively lower stiffness and strength, is to make hybrid films using biopolymers and nano-sized fillers known as nanocomposite films. In this research, the effect of bentonite nanoclay/chitosan ratio on the water vapor permeability (WVP), mechanical properties, and surface microstructure of the chitosan nanocomposite films was evaluated.

In this research, chitosan biopolymer aqueous solution with two concentration (2, and 3% w/v) and bentonite nanoclay solutions with two clay compositions (1 and 3% based on chitosan) were prepared, separately. The chitosan solution was then slowly added to the clay suspension at 55oC. The nanocomposite films were prepared using the solvent-casting method. The films based on 2 and 3% chitosan were considered as unfilled control samples. The water vapour permeability (WVP), tensile strength (TS), elongation at break (E), and microstructures of the films were investigated.

The results show that at identical concentrations of chitosan the amount of bentonite nanoclay affect the WVP and tensile strength (TS) of chitosan films, significantly (p<0.01). By adding 1% nanoclay bentonite to polymer matrix, the value of TS strength of nanocomposite film increased to approximately 0.66 (2% chitosan) and 0.35 MPa (3% chitosan). Moreover, the elongation value decreased to 8.8% and 6.47% in the nanocomposite films based on 2 and 3% chitosan, respectively. Further increase in clay content to 3 wt%, the WVP, elongation and TS of nanocomposites film decreased for chitosan 2 wt%. According to the SEM micrograph, non-homogeneous structure was found for 3% clay-chitosan nanocomposite in comparision to 1% nanoclay loaded chitosan nanocomposite in full agreement to the decrease in TS value observed. With increase the percentage of nanoclay bentonite to 3%, the pore spaces of film increased and consequently the TS exhibited decreased

According to the findings of this research, interactions between nanoclay and chitosan in nanoclay-chitosan nanocomposite have led to the formation of a new material with enhanced mechanical, morphological, and WVP properties than the pure chitosan. Finally, in 1% nanoclay concentration, the water vapor permeability, elongation, tensile strength, and also consistency of the microstructure films were significantly modified in compare of pure chitosan

In this study, bionanocomposite films enriched with Oregano essential oil (OEO) and OEO nanoliposomes (2% v/v) as a preservative agent on the rainbow trout fillets were used. Trout fillets were separated into four groups: unwrapped trout fillet (control), wrapped with nanocomposite based fish myofibrillar protein (FMP)-nanofibrillated cellulose (NFC) and wrapped with nanocomposites incorporated with 2% (v/v) OEO and OEO nanoliposomes. Trout fillets were analyzed for microbiological (total viable count, psychrotrophic count, Pseudomonas spp. counts and Enterobacteriaceae counts), sensory and color characteristics. The results of microbiological analysis showed that the highest rate of growth was observed respectively in trout fillets stored in air (control), wrapped with FMP-NFC nanocomposite and the lowest counts were in wrapped samples with nanocomposite enriched with OEO and OEO nanoliposomes (P

In this study, the effects of silver nanoparticles (AgNPs) at 1% wt and different concentrations of bacterial cellulose nanofiber (BCNF) (1.5-6% wt) on tensile properties (tensile strength -TS, elongation at break-EB, and Young’s modulus -YM), water vapor permeability (WVP), solubility, swelling, color properties and structural characteristics of chitosan nanocomposite films were studied. Response surface methodology (RSM) was used to determine the optimum amount of BCNF nanofiller. The optimization was based on maximizing TS, YM, EB, L*and decreasing WVP, solubility and swelling. The results showed that the AgNPs had a negative effect on mechanical and color properties of chitosan films. But incorporation of BCNF in the films improved their mechanical and barrier properties significantly. Lowest WVP, solubility and swelling of nanocomposite films was respectively for 6, 4 and 2%wt of BCNF content. Considering all physical and mechanical parameters, the optimal value calculated for BCNF, was 4.55%. SEM images showed BCNF uniformly distributed in the polymer matrix. DSC analysis confirmed that the addition of BCNF causes to improve the thermal properties of chitosan film.

New Polypyrrole-CuO nanocomposite modified polyester fibers have been prepared by solution polymerization in the basic solution in the presence of pyrrole, FeCl3 and CuCl2. The morphology of the Polypyrrole-CuO film on the surface of the fibers was examined by scanning electron microscope (SEM). The presence of the CuO particle in the polypyrrole-CuO nanocomposite was verified by FT-IR spectroscopy. The synthesized particles (30-150 nanometers) were observed according to the SEM results. The synthesized fiber was used as a headspace solid phase microextraction (HS-SPME) agent to extract VOCs from sesame oil and analysis by gas chromatography. The gas chromatogram profile of pure sesame oil and sesame oil samples mixed with different proportion of soybean oil was compared and used to authentication of pure sesame oil determination. The results showed that the VOCs profile of net sesame oil is different from adulterated oils. In the gas chromatogram profile 5 section of chromatogram distinguished (A=0-2, B=0-5, C=5-10, D=10-15 and E=15-20 minutes) and used for classification of different oil groups applying linear discrimination analysis (LDA). Data analysis showed that this technique has capability to detect adulteration of sesame oil with soybean oil.

In recent years using fresh foods that have undergone minimal processing, has become widespread. The use of biodegradable packaging is a new method for preserving of these products. The current research investigated the effect of different contents (1, 3, and 5 wt %) of montmorillonite (MMT) nanoclay on the physical properties of psyllium seed hydrocolloid nanocomposites. With the addition of up to 5% MMT, the tensile strength of the nanocomposite films increased from 11.60 to 17.08 MPa and the percent of elongation decreased from 30.42% to 19.02%. At the level of 5% MMT, the nanocomposite films showed the 35.04% reduction in the water vapor permeability in comparison to pure psyllium film. In addition, water solubility decreased when MMT was incorporated into the nanocomposite films. Scanning electron microscopy images indicates a good distribution for nanoclay particles in the biopolymer matrix. This
study revealed that the psyllium seed hydrocolloid had a good potential to be used in producing nanocomposite film with desirable characteristics.

Due to problems caused by petroleum-based packaging materials, biopolymers and their biodegradable films have received great attention all over the world in the last two decades. But the use of biopolymers films in food packaging due to their inherent water sensitivity and poor mechanical properties has been limited. A novel practical way for improving the properties of natural biopolymer films is the formation of nanocomposites. Thus, the main objectives of this study were to prepare alginate/clay nanocomposite films and to investigate the effect of montmorillonite concentrations on the properties of the prepared alginate-based nanocomposite films. A bio-based nanocomposite was developed by incorporation of clay nanoparticles (MMT) into alginate biopolymer using the solution casting method. The effect of MMT loading content (1, 3 and 5 wt%) on mechanical properties, color , water solubility, water vapor permeability, XRD and SEM of the nanocomposites were evaluated. Results showed that increasing the MMT content to 3% have improved the tensile strength and water vapor permeability of the nanocomposites up to 14% and 21%, respectively. The water solubility value of the nanocomposite films decreased about 30% compared to pure alginate films. Results of X-ray diffraction (XRD) revealed well developed exfoliated nanocomposite films especially at low level of nanoclay addition.
Properties of alginate films are greatly influenced by the content of the clay nanoparticles and the films containing 3% clay nanoparticles showed the best physical and mechanical properties.

Nanocomposites are prepared by introduction of dispersed nanoscale particles into the polymer matrix based on four template synthesis (sol-gel preparation); intercalation of polymer; and in situ intercalative polymerization and last one is melt blending, the most favorable and practical method due to its simplest, economical and environmentally friendly technic. This method involves annealing, statically or under shear, a mixture of the polymer and organically modified clay at the softening point of the polymer based on usual compounding devices, such as, extruders or mixers (Papaspyridesb 2008).
PET is a semicrystalline thermoplastic polyester which has been extensively used in all sizes as a packaging material in direct contact with food, beverages and as an alternative packaging to polyvinyl chloride for edible oils (Kirwan et al. 2011).
As polymeric nanocomposites are mainly used as structural materials, the layered silicate clay are preferred. The crystal lattice of 2:1 layered silicates, consists of two-dimensional layers where a central octahedral sheet of alumina is fused to two external silica tetrahedral by the tip. Montmorillonite (MMT) belongs to type 2:1 layered smectite clay which in the basic structure, the trivalent Al-cation in the octahedral layer is partially substituted by the divalent Mg-cation (Pavlidoua and Papaspyridesb 2008). As evident, MMT is greatly hydrophilic in the interlayer and incompatible with organic polymer such as PET, thus to increase compatibility of clay with polymer, inorganic inter-layer cations (Na, K or Ca2) exchanged by the cationic surfactants (e.g., quaternary ammonium salt). Modified MMT or organoclay interacts better with polymer due to its increased gallery space (Utracki et al. 2007; Parvinzadeh et al.2010).
Three different types polymer/clay nanocomposites can be obtained depending on the preparation method and the nature of the components used, including polymer matrix, layered silicate and organic cation. Tactoid nanocomposites formed when stacks of modified layered silicates are retained after introduction into the polymer. Subsequently, interaction between the nanolayers and polymer is not only unsuccessful but reduces mechanical properties of composite as well.
Our main objective of this research was to study the effect of the nanoclay addition on mechanical, colorimetric and transparency properties of poly (ethylene terephthalate) (PET) nanocmposite films.
Bottle-grade poly (ethylene terephthalate) granules with intrinsic viscosity of (IV) = 0.82 dl g-1 were provided by the Iranian Tondgooyan Petrochemical company. The organically modified montmorillonite, Cloisite 15A, was supplied by Southern Clay Products Inc. Standard of TPA was supplied from Fluka Chemical, trademarked Sigma-Aldrich Corp., Switzerland. High-pressure liquid chromatography (HPLC) grade water, aceto-nitrile, acetic acid and methanol (HPLC grade) were purchased from Merck (Darmstadt, Germany). TPA was dissolved into methanol with a slight increase in temperature. Working standard solutions were prepared on the day of use at concentrations of 0.4, 40, 100 and 1,000 ppb and calibration graphs were plotted using these concentrations of standard solutions.
The PET granules and nanoclay particles were dried in an oven for 24 h at 110 and 80C before extrusion, respectively. Melt blending technique was used for preparing nanocomposite films in a co-rotating twin screw extruder ZSK 25 .The temperature profile (throat to die) was as follows: 250, 270, 275, 270, 270 and 265C with a screw speed of 250 rpm. PET granules were dry mixed with 1, 3, and 5% wt of Cloisite 15A. The total weight of material per batch was 300 g. The resulting nano-composite strand was cooled in a water bath, granulated and dried overnight in oven at 110C. A laboratory press with a temperature plates of 280C under a pressure of 5 MPa for 10 min was applied to compress specimens. Then cooled them in water and ice bath to achieve transparent films.
The influence of different amount of nanoclay addition on resultant nanocmposites was studied by Fourier transform infrared spectroscopy (FT-IR) and mechanical test. Also, influence of nanoclay presence on water vapor permeability (WVP), color and transparency of the nanocomposites were investigated.
The results showed that nanoclay addition improved the mechanical properties (Young’s modulus, elongation at break and tensile strength) and WVP up to 3% (wt). However, nanoclay addition reduced the transparency of resultant nanocomposites films but it prevented wave transmission at three UV region which leads to better protective effect of film as a food packaging materials. It seems that introduction of Cloisite 15A into the PET matrix reinforced the mechanical properties of resultant nanocomposites. The Young’s modulus of the nanocompo-sites significantly increased compared with the neat PET, indicating that PET/Cloisite 15A nanocomposites were stiffer than PET. The maximum Young’s modulus was observed for PET/C15A containing 3% wt with an increment about 8 MPa. This increase in modulus may be attributed to uniform dispersion and alignment of nanoclay along with compatibil-ity with PET matrix as confirmed by XRD, DSC and SEM. The Young’s modulus enhancement is consistent with that of other research (KIMet al. 2007; Scaffaroet al. 2011; Ghanbari et al. 2013a,b]. Tensile strength like elongation at break shows same trend, increases on increasing nanoclay content except for nanocomposite containing 5% which indicates brittle behavior compared to PET. This can be explained consider-ing that higher aspect ratio of nanoclay tends to aggregate and forms tactoids (as shown in SEM and XRD) and conse-quently indicates poor mechanical properties.

Packing is a necessary steps to preserve the organoleptic, nutritional and Sanitary properties of food from production to consumption. Accumulation of irresolvable synthetic material Especially different types of packaging materials in nature In recent years has caused in recent years the use of biodegradable polymers strongly considered. In this study, possibility of Production of combining PVA and HPMC and their properties were studied. Finally, nano-composite films based on 80% PVA, and 20% HPMC contenting of the 1000, 2000 and 4000 ppm nanosilver were produced. Then characterization such as tensile, water vapor permeability, water uptake and were addition of Hydroxy Propyl Methyl Cellulose Improve the properties of films such as decrease water uptake, water vapor permeability and increase their strength and tensile strength. By addition of 2000 ppm nano silver to the film in some cases such as water vapor permeability, tensile strength, Young's modulus there was no Significant differenc e between the films with and without nano-silver. The nanocomposite films with high concentrations of nano-silver (4000 ppm) decrease the Young's modulus and tensile strength, In other words, leads to weakening the produced films. At high concentrations of nano-silver water vapor permeability increased. The antibacterial properties of nanocomposite films were evaluated by measuring the diameter of inhibition zone in a disk diffusion test against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Bacillus cereus (B. cereus).