Nanotechnology (packaging films, biocomposites, solar cells)
A. Nahalkar; A. Rajaei; H. Mirzaee Moghaddam
Abstract
This study investigated the effects of walnut oil incorporation on the physicomechanical and structural properties of sodium carboxymethyl cellulose-based edible films, with a focus on two methods of oil addition: bilayer and composite configurations. For this purpose, firstly walnut oil Pickering emulsion ...
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This study investigated the effects of walnut oil incorporation on the physicomechanical and structural properties of sodium carboxymethyl cellulose-based edible films, with a focus on two methods of oil addition: bilayer and composite configurations. For this purpose, firstly walnut oil Pickering emulsion (10% oil) was stabilized using chia seed gum, which was then incorporated into the formulation of bilayer and composite films. SEM revealed that bilayer film exhibited a more cohesive and homogeneous structure compared to the composite film. XRD analysis indicated a semi-crystalline amorphous structure across all films, with bilayer film displaying slightly sharper peaks than composite film. Moisture content and solubility tests highlighted the hydrophobic influence of walnut oil, with bilayer films exhibiting the lowest moisture content and solubility due to their surface-localized oil layer. Thermal analysis using DSC and TGA demonstrated improved thermal stability and reduced weight loss in bilayer film. Mechanical tests showed that the bilayer film had the highest elongation at break (34.3%) and the lowest tensile strength (3.4 MPa). Color analysis revealed significant changes in chromatic indices, with composite films showing higher saturation and total color difference. These findings underscore the potential of walnut oil emulsion stabilized with chia seed gum, particularly in bilayer configurations, to enhance the functional properties of sodium carboxymethyl cellulose-based films.
Nanotechnology (packaging films, biocomposites, solar cells)
N. Tajari; H. Sadrnia; F. Hosseini
Abstract
Polylactic acid (PLA) is a thermoplastic, biodegradable, and bioactive polymer obtained from renewable resources such as beets and potatoes. PLA is regarded as a polymer that is nearly brittle, which can restrict its applications in the packaging industry. The mechanical properties of this polymer can ...
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Polylactic acid (PLA) is a thermoplastic, biodegradable, and bioactive polymer obtained from renewable resources such as beets and potatoes. PLA is regarded as a polymer that is nearly brittle, which can restrict its applications in the packaging industry. The mechanical properties of this polymer can be improved by adding nanoparticles and plasticizers. In this research, zinc oxide nanoparticles (1 wt% of PLA), Polyethylene glycol 400 (20 wt% of PLA), and Polysorbate 80 (0.25 wt% of the solution) were used to improve the mechanical properties of PLA films. The effects of these materials on the films were measured at two time points: the first month and the tenth month, with the aim of investigating physical aging, a precursor to polymer degradation. Statistical analysis was performed on the mechanical properties measured during these periods to identify significant differences between the produced films. Results showed that the highest tensile strength (82.99± 1.90 MPa, neat PLA), elongation at break (76.82± 27.22 %, PLA/PEG/ZnO), toughness (20.13± 7.89 J cm-3, PLA/PEG/ZnO), and Young's modulus (2.74± 0.10 GPa, neat PLA) were observed in the first month. Analysis of variance results regarding the effect of time on each film revealed that in most cases, the mechanical properties did not change significantly after ten months. Based on the stress-strain curves, it was found that the neat PLA film is among the resistant materials. The PLA/Polysorbate/ZnO film exhibited brittle behavior in the tenth month. The remaining samples exhibited characteristics that fell between resistant and ductile materials in both the first and tenth months.
Nanotechnology (packaging films, biocomposites, solar cells)
H. Mirzaee Moghaddam; A. Nahalkar; A. Rajaei
Abstract
Pickering emulsion-based edible biodegradable films have emerged as a promising sustainable alternative to conventional food packaging materials. These films exhibit enhanced mechanical properties, including tensile strength, flexibility, and water vapor barrier performance, which are critical for maintaining ...
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Pickering emulsion-based edible biodegradable films have emerged as a promising sustainable alternative to conventional food packaging materials. These films exhibit enhanced mechanical properties, including tensile strength, flexibility, and water vapor barrier performance, which are critical for maintaining food integrity throughout storage and transportation. A key advancement in this field is the incorporation of essential oils into the emulsion matrix, which, despite their hydrophobic nature, significantly improve the functional and mechanical properties of polysaccharide-based films. This review examines the physicomechanical properties of polysaccharide-based edible biodegradable films incorporating Pickering emulsions, with a focus on flexibility, tensile strength, water vapor permeability, and moisture retention capacity. Furthermore, it explores the role of these films in extending food shelf life and analyzes how interactions between essential oils and polysaccharides influence their structural and barrier properties. Findings demonstrate that Pickering emulsions containing essential oils substantially enhance the mechanical and moisture barrier performance of edible biodegradable films. Solid stabilizing particles contribute to increased tensile strength, while essential oils improve flexibility—though excessive concentrations may compromise structural integrity. Additionally, these emulsions reduce water absorption and solubility, thereby improving film stability in humid conditions. Finally, this review examines the current challenges and identifies key research opportunities in the development of essential oil-loaded Pickering emulsion systems for polysaccharide-based biodegradable films, while outlining their potential for scalable industrial applications.
Nanotechnology (packaging films, biocomposites, solar cells)
N. Tajari; H. Sadrnia; F. Hosseini
Abstract
IntroductionPolylactic acid (PLA) is a biodegradable polymer that can replace petroleum-based materials in packaging films due to its unique properties. However, sometimes the degradability of polymers can be considered a negative factor, such as when significant changes in the mechanical properties ...
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IntroductionPolylactic acid (PLA) is a biodegradable polymer that can replace petroleum-based materials in packaging films due to its unique properties. However, sometimes the degradability of polymers can be considered a negative factor, such as when significant changes in the mechanical properties of the polymer occur during use. Another notable issue is the brittleness of polylactic acid, which can be modified to some extent by adding other materials. The addition of materials such as nanoparticles and plasticizers can improve the flexibility and mechanical properties of polymer films. Polymer films must possess acceptable physical, mechanical, thermal, and other relevant characteristics for use in the packaging industry. The acceptable level of these properties can be obtained by comparing them with the established standards for commonly used polymers in the industry. Low density polyethylene (LDPE) is a polymer widely used in the packaging industry, making it a good benchmark for comparison. This research focused on studying various factors affecting the quality of the produced films, including mechanical properties, light absorption, contact angle, and microstructures. Investigating the mechanical properties of the PLA films is crucial due to the polymer’s degradability over time. Polylactic acid films with different compounds containing PEG 400 and Tween 80 as plasticizers and ZnO nanoparticles were investigated for 14 months (in the first, second, third, fourth, and fourteenth months) in terms of mechanical properties. Finally, the obtained values were compared with standard values for packaging and their mechanical behavior was analyzed.Materials and MethodsExperiments were performed in the post-harvest and central laboratories of Ferdowsi University of Mashhad, Iran. The films were prepared using the solvent casting method. First, PLA granules were dried for 24 hours at 60 °C and then 1 g of PLA in 50 ml of dichloromethane was dissolved at room temperature by magnetic stirring for 12 hours. ZnO nanoparticles, PEG 400 and Tween 80 were incorporated into PLA and DCM solution, 1 wt% PLA, 20 wt% PLA, and 0.25 wt% solution, respectively. To prepare films containing nanoparticles, nanoparticles and dichloromethane were sonicated with an ultrasonic probe for 10 minutes and then added to the base solution and stirred for one hour.Mechanical properties of the samples were determined based on the ASTM D882-02 standard method. A texture analyzer (H5 KS, Manchester, U.K.) was used for this test. Light absorption was studied using a spectrophotometer (CAMSPECM550, UK). The contact angle of the samples was measured using a goniometer (model 200-00, Ramé-Hart Instrument Co, Succasunna, USA) in accordance with the ASTM D5946-04 standard. The surface morphology of the samples was visualized using scanning electron microscope (LMU TESCAN BRNO-Mira3, Czech Republic). The results were analyzed using Minitab software version 18 (Minitab Inc, USA) and the graphs were created in Microsoft Excel 2013.Results and DiscussionThe neat PLA film has a smooth surface, and with the addition of nanoparticles or plasticizers, the surfaces become uneven. The addition of nanoparticles and plasticizers caused more opacity of the film and better protection against ultraviolet rays. The presence of plasticizers, especially Tween 80, increased the hydrophilicity of the films. Packaging films should be flexible and have ductile behavior and the addition of plasticizers caused ductile behavior. However, Tween 80 was not able to create stable ductile behavior. The stress-strain diagram shows that most samples displayed ductile behavior over 14 months, except for the neat PLA film and the film containing Tween 80 and nanoparticles. The values of tensile strength, elastic modulus, and elongation at break for low density polyethylene have been reported as 11.7 MPa, 260.4 MPa, and 225%, respectively. The lowest value of tensile strength (18.56 MPa) and elastic modulus (1114.68 MPa) were related to P400/T80 film. This difference shows the acceptability of polylactic acid in the packaging industry. The elongation value is much lower than the standard, indicating the need to modify this parameter.ConclusionThe research findings revealed a significant effect of film type on mechanical properties, as well as a remarkable impact of storage time on tensile strength and elongation at break. The effect of various factors such as changes in the texture of the film due to the presence of plasticizers or non-uniform distribution of nanoparticles makes it impossible to determine a consistent trend for the effect of time on the films. The elongation at break for the produced films was much lower than the standard, which still needs to be modified due to the importance and sensitivity of this parameter in packaging. Polylactic acid has high tensile strength and high elastic modulus. Therefore, it can be combined with other polymers, various plasticizers, or nanoparticles at higher percentage to improve flexibility. The presence of plasticizers and nanoparticles in the film substrate increased opacity and enhanced protection against ultraviolet rays. The produced films were more hydrophilic compared to low density polyethylene.Acknowledgment This research was supported by Ferdowsi University of Mashhad (Grant No. 54096). The authors would like to thank Dr. Mohammadreza Pajohi-Alamoti, Department of Food Hygiene and Quality Control, Bu-Ali Sina University, Hamedan, Iran for providing polylactic acid granules.
Nanotechnology (packaging films, biocomposites, solar cells)
F. Amirshaghaghi; H. Sharifnasab
Abstract
Introduction: In order to improve the use of pesticides and pesticide consumption and prevent environmental pollution, manufactures and scientists have considered two major trends. The first major trend is improving techniques that are practical and effective use of small quantities of chemicals to reduce ...
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Introduction: In order to improve the use of pesticides and pesticide consumption and prevent environmental pollution, manufactures and scientists have considered two major trends. The first major trend is improving techniques that are practical and effective use of small quantities of chemicals to reduce the negative effect of residues of pesticides. The use of new methods usually requires investment and cost. The second major trend is changing the parts that are more important to reform the sprayer components in order to reduce pollution, mainly by including engineering controls, and design and construction of appropriate nozzles. The optimization can be done with the least expensive pesticide. Nozzle is a device for spraying the solution in the form of particles with a certain pattern. Tip of a nozzle is placed in the nozzle’s body and has many different types. The main factors in choosing tips include: material, pattern of distribution, spray angle and the amount of the solution. The spray tip may be made of aluminum, brass, nylon, stainless steel, ceramic or other materials. Nanocomposites are composites that contain at least one component with dimensions in the nanometer range between 1 to 100 nm. This material is suitable as an alternative to overcome the limitations that exist with integrated microcomposites. The aim of this study was the construction and evaluation of a sprayer nozzle with ceramic nanocomposites with good shelf life and optimum performance.Materials and methods: This research was supported by the Agricultural Engineering Research Institute and Nanotechnology Committee of the Ministry of Agriculture. The operations of this study were as follows: 1- Preparing of materials, including alumina powder and stabilized zirconia powder with yttrium. 2- Design and manufacture of molds. 3- Preparation of the samples pressing operations. 4- Zintering of samples to achieve high density. 5- Tests to determine the quality of the products. In order to prepare nanocomposite powder mixed with stabilized zirconia alumina, the ratio of 10/90 percent by volume of the powder was poured into the mill for three hours and it was stirred in the mixer. Pressing is placing the powder into a mold, and applying pressure to achieve the desired density. In this study, pressing device with 30 tons was manually used and powder sample in the amount of one gram was placed in a semi-cylindrical small hollow. After making a few samples and determining the optimal pressure and time of pressing in action, samples were manufactured under 90 kg cm-2 pressure at 20 seconds. A high temperature furnace model F3L-1720 was used for zintering. Samples were put into the furnace after forming by a single-axis press. Temperature the of furnace was raised up 1650°C at a rate of 10 degrees per minute and then the samples were exposed for one hour in order for the heat to be evenly applied in all the body of the nozzle. Finally, a hollow cone spray pattern fan nozzle with a major diameter of 15 mm and an inner diameter of 2 mm was built. Equipment for analyzing used in this study included: X-Ray Diffraction device (XRD), Scanning Electron Microscope (SEM). The flow rate output was measured at a pressure of 2 bar in the period of 0-50 hours at 1, 2, 3, 4, 5, 8, 10, 15, 20, 25, 30, 40 and 50 hours.Results and Discussion: XRD analysis of nano-composite stabilizer in the presence of yttria- zirconia- alumina toughness with (Al2O3-ZrO2-Y2O3), yttria stabilized zirconia (ZrO2-Y2O3) and alumina indicates respective phases. For the samples made with better properties, it should be uniformly distributed within it. To evaluate the uniformity, SEM-Mapping test samples were made. The results showed that the distribution of Y, Zr, Al in nanocomposite (Al2O3-ZrO2-Y2O3) is almost uniform. The results of changes in the level of output over time showed that the rate of flow in composite (Al2O3-ZrO2-Y2O3) nozzle versus ceramic conventional (Al2O3) nozzle after 50 hours of testing under static condition, flow rate was decreased to 30- 35 percent.Conclusions: Nozzles are one of the most important terminal parts in sprayers and are used to spread the liquid evenly at a certain flow rate. Addinga nanomaterial ceramic structure as a new solution was effective. By paying attention to reduce the use of chemicals and protection of the resource bases, a correct approach to the development of agricultural mechanization equipment that are essential components should be a priorityas a low-cost solution.
