Showing 22 results for Nanocomposites
Seyed Mohamad Reza Paran, Ghasem Naderi, Mir Hamidreza Ghoreishy,
Volume 1, Issue 1 (12-2017)
Abstract
Oil resistant o-rings on the basis of acrylonitrile butadiene rubber (NBR) reinforced by nanoclay were produced via a traditional industrial method in accordance with aviation standard, AMS 7272. The production of nanocomposites comprised the compounding of nanocomposite with optimum mechanical properties and minimum contents of used carbon black and nanoclay, design and manufacturing of the required mold and finally compression molding of the oring. Mechanical and morphological properties of NBR/nanoclay compounds were optimized by introduction of proper contents of a compatibilizer containing a mixture of resorcinol and hexamethylene tetramine through using a master batch production method. The prepared nanocomposites were characterized using X-ray diffraction (XRD) analysis, curing measurements and tensile test analysis. The XRD analysis showed that the compatibilizer facilitates the intercalation of nanoclay silicate layers with the rubber chains which leads to the increase of their basal spacing. The cure characteristics of the nanocomposites showed a decrease of scorch time and increase the cure rate index with the nanoclay loadings. Furthermore, the minimum scorch time and maximum cure rate index could be achieved through using the appropriate content of compatibilizer. The results exhibit that the nanocomposites containing the compatibilizer have higher mechanical properties especially at higher deformations compared to the corresponding uncompatibilized nanocomposites
Navid Ebrahimi, Gita Bagheri,
Volume 4, Issue 3 (12-2020)
Abstract
Metformin enhances insulin's effect and increases cells’ sensitivity to insulin. In this paper, nanocomposite was designed and used in the metformin release system, which was able to release the required drug in a controlled manner. In this research, nanoparticles of zinc oxide (ZnO) were prepared via the sol-gel method. The experimental design central composite response surface method was applied for the optimization of the nanoparticles based on varied variables such as the weight of zinc acetate (gr) (X 1) and the volume of triethanolamine (ml) (X2). The particle size of the optimized nanoparticle was reported to be 28 ± 21.27 nm; zeta potential and PdI were 25.54 ± 1.64 mV, 0.168 ± 0.05 respectively. The chitosan polymer was used to improve environmental compatibility and increase drug release control; finally, metformin was loaded on the optimized nanocomposite. Structural properties were analyzed using scanning electron microscopy (SEM) X-Ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and Dynamic Light Scattering (DLS). The SEM images showed that the average nanocomposite size was 40 nm. The results of XRD patterns and SEM images were also consistent with each other and the average particle size was the same. Infrared spectrophotometry showed the presence of chitosan used to coat nanoparticles on their surfaces and confirmed the loading of metformin. An in-vitro metformin release from the nanocomposite was conducted in PBS (pH=7.4) and analyzed by a spectrophotometer at 233 nm. Metformin has a high solubility in water, and since it is difficult to prepare a slow release form of high-solubility drugs, the aim of this study was to design a slow-release formulation of metformin with a suitable profile that could control release without explosive release for up to 120 hours.
Hamidreza Azimi, Davoud Jahani, Amin Mohebifar, Mohamad Reza Yazdan Panah,
Volume 5, Issue 1 (7-2021)
Abstract
Research subject:Well-designed plastic foams, with respect to their cell density and cell size, open-or-close cells, and the cell uniformity, compared to their counterpart unfoamed plastic parts, beside of having the advantages of less material consumption, dimensional stability, better processability, and a higher surface quality, they can have superior mechanical and physical properties, including strength to weight, impact strength, thermal and dielectric properties. The temperature distribution in the different zones of the extruder, the qualities and quantities of the nanoparticle additives and their dispersion in the polymer matrix can have significant effect on the mechanical properties of the produced foams by the extruder.
Research approach: In this study, using an extruder, MA-g-polypropylene microcellular foams, containing 3, 7 and 9 wt% of nano-clay particles, were produced under three temperature arrangements on the extruder and the material and the processing effects on the mechanical properties were investigated.
Main results: The result of this investigation shows that adding of nanoclay improves the mechanical properties of MA-g-PP.s foams. As an example, the results show that the sample with 7 wt% of surface modified nanoclay, owns about 10% higher impact toughness compared to the samples produced without nanoclay. Also for the same samples a rise of about 5% was recorded in Young's modulus. The microstructural studies of the produced foams by scanning electron microscope (SEM) show that adding of nanoclay can result on more foam uniformity and smaller cell size. In this study, the smallest average cell size (87.5 μm) and the lowest density (0.3 g/cm3) were recorded for a sample with 7wt% nanoclay.
Seyed Mehdi Mirabolghasemi, Mohsen Najafi, Alireza Azizi, Mehdi Haji Bagherian,
Volume 5, Issue 3 (12-2021)
Abstract
Research subject: Biodegradable compounds with high mechanical and thermal properties are one of the intersting research topics. Polylactic acid is an aliphatic polyester with high biodegradability and flexibility. It, however, suffers from several weaknesses such as high permeability to water vapor and gases, low glass transition temperature, poor thermal stability and brittleness which can be improved by the incorporation of nano-scale fillers giving rise to bionanocomposites. The aim of this study was to investigate the effect of the simultaneous incorporation of cellulose nanocrystals and nanosilver on the mechanical, thermal and water vapor permeability behavior of polylactic acid-based films.
Research approach: Polylactic acid films and their bionanocomposites containing different levels of cellulose nanocrystals (0.01, 0.03 and 0.05 g) and nanosilver (0.01 g) were prepared by solution casting method. To improve compatibility and miscibility of the polymer, cellulose nanocrystals were reacted with acetic anhydride and modified. FTIR spectroscopy, tensile test, thermal properties (DSC), migration test and antibacterial properties were used to study the properties of the samples. The water vapor permeability of the samples were also measured.
Main results: The addition of cellulose nanocrystals, increased the glass transition temperature (Tg) and melting point (Tm) of the samples. The presence of cellulose nanocrystals increased the tensile strength and modulus of elasticity of the bionanocomposite relative to pure polylactic acid. With the addition of cellulose nanocrystals, permeability was reduced by about 25%. As the amount of cellulose nanocrystals increased, the swelling and water absorption of the samples increased significantly. The migration rate of the samples also decreased after the addition of nanocellulose.
Volume 9, Issue 4 (12-2018)
Abstract
Aims: The simultaneous use of insulating polymers and nanostructures such as silver to produce triangular nanocomposites, with the reinforcement of effect of each other, can have better results in improving the mechanical properties and processability of polyaniline. The current study was conducted with the aim of preparation of Polyaniline/Polyvinyl Alcohol/Ag nanocomposite and characterization of its physicochemical and antibacterial properties.
Materials and Methods: In the present experimental research, polyaniline (PANI) was used as a conducting polymer, polyvinyl alcohol (PVA) was used as a biopolymer because of its biodegradable property. Ag nanoparticles also was considered as a reinforcing agent of thermal stability, mechanical and antibacterial property to prepare PANI-PVA-Ag nanocomposite.
The synthesis of PANI-PVA composite and PANI-PVA-Ag nanocomposite was performed through polyaniline and Ag addition in PVA solution. Different weight percent of components and Fourier-Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and scanning electron microscope connected to the X-ray Diffraction System (EDX) were used to investigate the properties.
Findings: Thermal stability of the nanocomposite in comparison with pure PVA in temperatures above 400ᵒC was promoted. The presence of PANI, PVA, and Ag in the FTIR spectroscopy showed the compatibility of the nanocomposite components. The greatest tensile strength belonged to PANI/PVA/Ag nanocomposites with 88%, 9%, and 3%w/w.
Conclusion: The components of Polyaniline/Polyvinyl Alcohol/Ag are compatible. The presence of PANI and Ag nanoparticles in the structure of the nanocomposite improves its thermal stability than pure PVA at high temperatures. Polyaniline/Polyvinyl Alcohol/Ag canocomposite has inhibitory effect on gram-positive and gram-negative pathogenic bacteria. Reducing the weight percent of PVA or increasing the weight percent of PANI decrease the tensile strength.
Volume 12, Issue 1 (4-2012)
Abstract
In this paper, the influence of nanoclay Closite 30B on ballistic impact behavior of 2D woven E- Glass/Epoxy laminated composite has been investigated experimentally. The glass/epoxy/nanoclay laminate nanocomposites have 12 layers and 60% fiber volume fraction is manufactured by VRTM method. Fibers have a plain weave configuration with density of 200gr/m2, while The epoxy resin system is made of a diglycidyl ether of bisphenol A (DGEBA), Epon 828, as the epoxy prepolymer and a polyoxypropylene diamine with average molecular weight of 400 gr/mol, Jeffamine D-400, as the curing agent. The nanoclay Closite 30B is dispersed into the epoxy system in a 0%, 1%, 2%, 3%, 5% and 7% ratio in weight with respect to the matrix. Morphological studies using XRD revealed that nanostructures are mostly in intercalated form rather than exfoliated form. In additional to tensile test, ballistic impact test is carried out on the samples by flat-ended projectile with 14gr mass and 9.77mm diameter in 130m/s, 142m/s and 155m/s velocities. The results have shown that not only the mechanical properties, but also ballistic impact resistance can be improved with adding nanoclay.
Volume 13, Issue 4 (7-2013)
Abstract
In this paper, the influence of nanoclay Closite 30B on ballistic impact behavior of 2D woven E- Glass/Epoxy laminated composite has been investigated experimentally. The glass/epoxy/nanoclay hybrid laminate nanocomposites are manufactured by layup method under pressure. The nanoclay particles are Closite 30B and are dispersed into the epoxy system in a 0%, 3%, 5%, 7% and 7% ratio in weight with respect to the matrix. In additional to tensile test, ballistic impact test is carried out on the samples by flat-ended projectile with 8.9gr mass and 10mm diameter in 134m/s and 169m/s velocities. The results have shown that not only the mechanical properties, but also ballistic impact resistance can be improved with adding nanoclay.
Volume 13, Issue 5 (8-2013)
Abstract
Abstract-In this study,nanocomposites based on polypropylene and polyethylene containing 0 to 7phr of nanoclay and 3phr of maleated polypropylene (PP-g-MA) and maleated polyethylene (PE-g-MA) as compatibilizer were prepared by melt compounding followed by injection molding.Morphology of the mixtures was carried out through Field Emission Scanning Electron Microscopy (FESEM). Mechanical properties of different samples were examined empirically by tension and izodimpact tests.Test results show that the addition of clay particles to the PP and LLDPE, increases the tensile strength, yield strength, tensile modulus and decreases impact strength and elongation at break compared to pure polymer.Themixture design method and Minitab16 software were utilized for designing the tests, statistical analyses, and optimization the mechanical properties of the mixtures.Results showed that the in compounds based on polypropylene and polyethylene, respectively, compounds includes 3.96 and 2.12percent clay has the best mechanical properties.blends base on PP have better tensile modulus and LLDPE blends have better impact strength.
Volume 13, Issue 6 (9-2013)
Abstract
In this paper, the influence of nanoclay Closite 30B on ballistic impact behavior of 2D woven E- Glass/Epoxy laminated composite has been investigated Theoretical and experimentally. The structure of the hybrid nanocomposite is glass/epoxy/nanoclay laminate and is manufactured by hand layup method under pressure. The nanoclay is dispersed into the epoxy system in a 0%, 3%, 5%, 7% and 7% ratio in weight with respect to the matrix. Comparison of theoretical results and results of the ballistic impact test are shown a good correlation. The results have shown that optimal to increase in energy absorption is 10% in 3% nanoclay content. Howevere, in the impact velocities far than ballistic impact, maximum increasing in energy absorption is 20% in 10% nanoclay content.
Volume 13, Issue 11 (1-2014)
Abstract
Graphene/Polypropylene nanocomposite is a new material and limited research is performed on mechanical properties of such material. A random distribution of the nano particles in the matrix has a special importance in having proper mechanical properties for Graphene/Polypropylene nanocomposites. To have a uniform distribution of the nano graphene in the polypropylene, a method developed by Kalaitzidou, et al. for distribution of exfoliated graphite in polypropylene is used in this research. In this paper, Polypropylene is coated with graphene and then the nanocomposite specimens are made using melt-blending and injection molding. Polypropylene reinforced with 0.5, 1.0 and 2.0 wt% graphene sheets were prepared and their tensile properties are investigated. Good enhancement of Young’s modulus and yield stress at very low graphene contents are achieved. The results indicate that the mentioned method is suitable for fabrication of graphene/polypropylene nanocomposites, which yields a good dispersion of graphene in the polypropylene.
Volume 13, Issue 12 (2-2014)
Abstract
Application of carbon nanotube reinforced polymers in space industry is widely dispread due to the unique and multi-purpose properties of them Therefore, extraction of electrical and electromagnetic properties of nanocomposite materials in the frequency band of 12.4 to 18 GHz is an important issue in their development procedure. In this paper, experimental investigations on electrical and electromagnetic properties of carbon nanotube reinforced polymers are performed. The investigated properties include AC and DC electrical conductivities, permittivity, transmission and reflection coefficients, loss tangent and skin depth in Ku frequency band (12.4-18 GHz). The in situ polymerization method is selected to fabricate multi-walled carbon nanotube (MWCNT)/Vinylester nanocomposite. Ultrasonic device is used for dispersion of CNTs in resin and then Vector Network Analyzer (VNA) is employed for measurement of electrical properties of specimens. Weight fraction of MWCNT is chosen between 0.1 to 3 % in order to evaluate the influence of CNT content on investigated properties. Finally, equivalent circuit model is used to describe the observed behavior on the basis of semi-empirical study.
Volume 13, Issue 12 (2-2014)
Abstract
The main purpose of the present research is analytical and numerical analyses of graphene/epoxy nanocomposites with a random distribution of nanoparticles. For this purpose, by combining the molecular dynamics and micromechanics methods, a new approach is presented. The molecular dynamics method is used to model the stiffness of the graphene/epoxy nanocomposites containing one layer of nano graphene embedded in epoxy resin. A multi-scale modeling strategy from macro to meso, then from meso to micro and finally from micro to nano scales is introduced. A representative volume element (RVE) is selected and for a nanocomposite having a single monolayer graphene embedded in epoxy resin, the longitudinal (E11), transverse (E22) and normal (E33) stiffnesses for three RVEs with arbitary graphene size are simulated. The best curve is fitted to each stiffness diagram and stiffnesses of the RVE in three directions with true graphene size are investigated. In order to consider the effect of randomly graphene sheets distribution in epoxy resin, micromechanical approach is used. Finally, the stiffness of the nanocomposites with randomly distributed graphene is calculated. For evaluation of the present approach in this research an experimental program is conducted. The result of the modeling is well agreed with the experimental data.
Volume 13, Issue 13 (3-2014)
Abstract
In this study, various amounts of clay nanoparticles and titan nanoparticles (1, 3 and 5% wt.) were introduced into a vinyl ester resin matrix by high shear mixer. The influence of these nanoparticles on the mechanical properties (tensile strength, tensile modulus, flexural strength, flexural strength and fracture toughness) is investigated. To investigate the structure of nanocomposites, X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests are done. The XRD test shows that the structure of clay-vinyl ester nanocomposites is exfoliated. The results of tensile, flexural and fracture toughness experiments show that clay is better than titan in the improvement of the mechanical properties. Clay- vinyl ester nanocomposite with 1% wt. of clay has the better mechanical properties than others samples.
Volume 13, Issue 51 (7-2016)
Abstract
The main functions of the packages are: Physical protection, barrier protection, convenience and information. Tendency to minim process food products, quality, safety and preventing of food born disease and strict requirements in relation to consumer health caused ways to use antimicrobial agents in food packaging and prevent the development of microorganism growth. Active packaging is one the methods of efficient packaging, that protect safety and quality of foods. The material of these packages is a suitable base for adding a wide range of different combinations such as antimicrobial agents to them. Pursuant to this, movie bionanocomposite films of Bitter vetch seed’s protein with zinc oxide nanoparticles to produce an antimicrobial packages with %5 w/w of Bitter vetch protein isolate and 0.25, 1 and 2% zinc oxide nanoparticles. Glycerol was used as plasticizer. The mechanical and barrier properties of bionanocomposite films assessment and determined that the addition of zinc oxide nanoparticles as an antimicrobial agent to the protein film caused a sharp decrease of oxygen permeability through the films. The rate of water vapor permeability of bionanocomposite films decreased comparing with control film. The results indicated that lower levels concentrations of nanoparticles cause better functional properties of bionanocomposites films because of fewer particles coagulation. Effect of nanoparticles on the mechanical properties, tensile strength and modulus of elasticity were increased, but elongation of the film was reduced.
Volume 13, Issue 56 (10-2015)
Abstract
In this study, low soluble and mechanical-tension resistant nanocomposite films were developed by adding different concentrations (5, 10 and 15% dw) of nanoclay type Cloisite Na+ (CNa+) to the soy flour polysaccharide. In order to investigate the physico-mechanical, structural and thermal properties of the developed nanocomposite, it has been synthetized by soluble molding method. When the nanoclaywas added to the biopolymer film, water solubility decreased, although the aforementioned trend was more significant when the concentration of the nanoclaywas raised. The film transparency was significantly declined when the nanoclay was added. By adding the nanoparticle, the film strength increased and this was increased when the nanoparticle concentration increased. Elongation at break decreased when the nanoparticle concentration was increased. The XRD results indicate that pure film specimen is amorphous whereas the biopolymer structure is becoming order and crystallinity increased when the nanoparticle was increased. These results revealed the peaks shifting to the lower degrees, increasing the interspace between nanoclaylayers and intercalation. From morphological point of view, a homogenous texture caused by adding nanoparticle to the polymer matrix was investigated using SEM. This study aimed to be successful for using the soy polysaccharide film as well as nanoparticle in order to introduce a new film in which used for nanocomposite synthetize.
Volume 14, Issue 7 (10-2014)
Abstract
In this paper, the influence of nanoclay Closite 30B on the tensile and the bending properties of 2D woven E- Glass/Epoxy laminated composite have been investigated experimentally. The glass/epoxy/nanoclay laminate have 12 layers and 60% fiber volume fractionis is manufactured by VRTM method. Fibers have a plain-weave configuration with density of 200 gr/m2, while the nano-epoxy resin system is made of diglycidyl ether of bisphenol A (epon 828) resin with jeffamine D400 as the curing agent and an organically modified MMT in a platelet form, namely Closite 30B. The nanoclay is dispersed into the epoxy system in a 0%, 3%, 5%, 7% and 7% ratio in weight with respect to the nano-matrix. The results have shown that Maximum to increase in the tensile and the bending properties are in 3% and 10% nanoclay content. The maximum to increase in the tensile strength, the failure strain and toughness are 13%, 7% and 27% respectively in 7% nanoclay content and in the modulus is 9% in 3% nanoclay content. Moreover, the maximum to increase in the flexural strength is 11% in 3% nanoclay content and in flexural modulus is 48% in 5% nanoclay content.
Volume 15, Issue 2 (4-2015)
Abstract
This paper deals with the design and fabrication of an adjustable, two fingers flexible miniature gripper based on porous magnetorheological nanocomposites having the adjustability of pre-openings of the jaw’s tips and its operational study in according to the performance. The fabricated gripper holds the small size and lightweight objects, maintain them and release them as required upon reducing the electrical current. The magnetic analysis has done and magnetic simulation has conducted using Vizimag software. The lead, condensed papers, foams and silicon wafer sheets were used as under experiments materials and it has been noticed that it is working properly to grip the things which has rough surfaces at all. For a greater objects, it can be adjusted through its tips as well. In this scheme, the magnetic actuation has been used because the magnetorheological nanocomposites is the most sensitive materials against the magnetic field. This type of grippers includes the simple montage, lower fabrication prices and owns lower volume as well as weight, and there will be no need to apply the classic mechanical linkage inside. This type of grippers are recommended for applications in the fields of the micro electromechanical systems, especially in the holding and transporting of sensitive work pieces against scratches, fingerprints and pressure.
Volume 16, Issue 1 (3-2016)
Abstract
In the present paper, to determine the pressure-dependent yield surface of polypropylene/nanoclay nanocomposites, the extended Drucker-Prager yield criterion is used and its parameters are derived by a combined experimental/numerical/optimization approach. In this method, the difference between the experimental and numerical results obtained from three-point bending test is minimized. In order to alleviate the burdensome numerical simulation, a surrogate model based on Kriging method is used to estimate the cost function. The optimum of this function is obtained by maximizing expected improvement method. Afterward, the results are verified by tension and compression tests. The results show that this method can substitute the complicated experimental tests which are normally employed to identify the extended Drucker-Prager parameters. Also, this method can be used to determine the mechanical properties of thermoplastic material such as tensile and compressive yield stresses and elastic modulus using only a three-point bending test. In addition, it is found that the volumetric change of thermoplastic during plastic deformation is significant and the non-associative, compared with the associative, plastic flow assumption is more proper for this material for the extended Drucker-Prager criterion.
Volume 16, Issue 9 (11-2016)
Abstract
In this research, a three dimensional analytical method is presented for predicting the dynamic properties of polymer nanocomposites. In the present method elastic-viscoelastic correspondence principle is applied on the simplified method of cell, and loss modulus, storage modulus, loss factor and Hysteresis loop are obtained using energy method as well as force balance method. The considered nanocomposite possesses Polypropylene as a matrix reinforced by vapor grown carbon fibers. The rrepresentative volume element consists of three isotropic phases including fiber, interphase and matrix with linear viscoelastic behavior based on Zener model. Furthermore the nanocomposite constituents dynamic properties are extracted in frequency domain by employing Fourier transform method and Schapery model First to assure the validation of the model, the results are compared with experimental results. Parametric studies such as the effects of number of subcells, fibers volume fraction (FVF) and aspect ratio, matrix/fiber link strength factor and interphase loss factor on the nanocomposite dynamic properties are investigated.. Obtained results reveal that the presented method has acceptable speed and accuracy. Moreover fiber aspect ratio and FVF increasing leads to decrease the nanocomposite hysteresis loop area, subsequently its damping capacity reduces. Interphase also contains considerable effects on the nanocomposite dynamic properties, so its modeling has a great importance.
Volume 17, Issue 1 (3-2017)
Abstract
Nanoparticles are being used nowadays to improve the mechanical and structural specification of Fiber Reinforced polymers (FRPs) due to production of hybrid & Multi scale composites. Electrophoretic deposition has been utilized to deposit a smooth layer of carbon nanoparticles on the surface of woven glass fibers, and later in the fiber/matrix interface of composite structure. Initially, the experimental parameters in deposition of CNTs investigated. Suspension concentration, field strength and process duration effects has been studied on the quality and quantity of deposition mass. Then the best situation has been used to fabricate CNT reinforced glass fiber-epoxy composite to evaluate its short beam strength and also quasi static indentation performance subject to lateral shear loads. Results demonstrates the salient effect of grafted CNTs in the nanocomposites interface on their mechanical behavior. The interlaminar shear strength of prepared nanocomposites has been increased by 42% regarding control samples and 10% improvement achieved in their quasi static performance. It has been shown that there is a range of optimum values for field and concentration due to stability of process and also deposition mass. The stability of process will restrain the field and concentration in the process. In best practices the current density values encountered between 0.5 and 1 mA/Cm2. The effect of field strength was around 8.5 times, but the effect of concentration was around 5.5 times. The current density diagram was steady in stable processes and the first three minutes of each process known as the effective deposition time.
