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nanocomposites
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Fabrication and Characterization of Bioactive PLGA- TiO2 Nanocomposite Scaffold by Air-liquid Foaming for Bone Tissue Engineering
, Ph.D. Dissertation Sharif University of Technology ; Madaah Hosseini, Hamid Reza (Supervisor) ; Samadi Kuchaksaraei, Ali (Co-Supervisor)
Abstract
Poly (lactate-co-glycolate) is a typical biocompatible and biodegradable synthetic polymer. Addition of TiO2 nanoparticles improved compressive modulus of PLGA scaffolds and reduced fast degradation. Porous 3D scaffolds, which are synthesized using biocompatible and biodegradable materials, could provide suitable microenvironment and mechanical support for optimal cell growth and function. A novel method has been applied to fabricate PLGA/TiO2 scaffolds without using any organic solvent or porogen for nucleation compared to former ways, with aim of improving the biocompatibility, macroscale morphology and well inter-connected pores efficacy: Air-Liquid Foaming. Adjustment of the foaming...
Oxygen Barrier Improvement of the BOPP Films in Food Industry
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
One of the most popular methods in order to protect foods is to package using various materials. By this act, the shelf life of the packaged foods may range from a few days to more than a year. Multiple types of plastics are being used as materials for packaging food, including polyolefin, polyester, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, and ethylene vinyl alcohol. Although more than 30 types of plastics have been used as packaging materials, polyolefin and polyesters are the most common. Biaxially Oriented Polypropylene (BOPP) is a polypropylene film that has been stretched in both the machine and cross directions. BOPP film has become one of the most popular...
Synthesis and Antibacterial Activity of TiO2/ZnO Nanocomposite via Sol-Gel Method
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
The synthesis and usage of TiO2/ZnO nanocomposite thin film in antibacterial activity against E-coli were experimented through a systematic research. TiO2/ZnO nanocomposite films can demonstrate different properties like gas sensing, self cleaning and treatment of the broad range of aqueous pollutants when it is exposed to light with wavelengths less than 400 nm. This phenomenon happens because of the photocatalytic reactions in the nanocomposite thin film which cause active species production on the surface of the thin film. The nanocomposite synthesis was based on sol-gel process in atmospheric pressure. In this study titanium dioxide is prepared by sol gel method from titanium...
Electrodeposition of Cu/WC Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Afshar, Abdollah (Supervisor)Electrodeposition of Ni-Co/SiC Composite Coatings
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Ni-Co/SiC composite coatings with various contents of SiC nano particles were electrodeposited in a modified watt type of Ni-Co bath containing 20 nm SiC nano particles to be codeposited. The influences of the SiC concentration, current density, stirring rate of the deposition bath on the composition of the coatings were investigated and these parameters optimized for highest amount of SiC codeposition. The optimized deposition parameters were 40 g/l SiC and 480 rpm stirring rate and current density equal to 4 A/dm2. Ni-Co/SiC composite coating was deposited with the maximum particles content of 30.5 volume percent. Linear voltammetry demonstrates addition of the SiC to the Ni-Co deposition...
Investigation Ni-P-Al2O3-SiO2 Nano Composite Coating on Aluminum by Electroless
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Electroless coating is a chemical reduction process which depends on the catalytic reduction. In this study, the influences of different concentrations, stirring rate, pH and heat treatment of Al2O3 and SiO2 Nano sized particles in the bath on deposition rate, hardness, wear resistant, surface morphology and corrosion behavior of the Ni-P-Al2O3-SiO2 composite coatings have been investigated. The microstructure was investigated by field emission scanning electron microscopy (FESEM) and among the nanoparticles SiO2 and Al2O3 have drawn attention due to their high hardness, availability, particles distribution and reduced cost. The amount of Al2O3 and SiO2 was examined by Energy Dispersive...
Synthesis of Titanium Dioxide-graphene Nanocomposite: Characterization and Photocatalyst Applications
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
TiO2 and TiO2-Graphene have been synthesized by hydrothermal method. Their physical, chemical and morphological properties have been investigated using XPS, XRD, FTIR, TEM, EDX, UV-Vis and AFM analyses. Moreover, photocatalytic efficiency of prepared materials has been examined using degradation of methylene blue. AFM image exhibited that monolayer GO with thickness of 10 nm was synthesized using modified Hummer’s method. FTIR analysis represented main characteristic peak of oxygen bond on the surface of GO, whereas for TiO2-Graphene most of oxygen functionalities on the surface were removed partially or completely. Photocatalytic degradation of MB proved this extension of light absorption....
Preparation of Biodegradeble Nanocomposite with Appropriate Physical and Mechanical Properties for Bread Packaging
, M.Sc. Thesis Sharif University of Technology ; Ramezani Saadat, Ahmad (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
Platelet nanoparticles could dramatically decrease permeability of polymeric film where increase considerably its physical -mechanical properties. Bio based (Biodegradable) polymeric materials such as starch based polymeric films show very weak mechanical and high oxygen and water vapor permeability. Graphene oxide (GO) could increase mechanical properties of starch based polymer where decrease its permeability dramatically. Addition of chitosan also could increase antibacterial and antifungal of films and decrease permeability of films considerably. In this research nanocomposite of Starch/Chitosan/GO films have been prepared by solution method and its morphology, permeability, physical...
Synthesis of Silver Based Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
Recently, conductive nanocomposites have found great deals of attentions due to their vast applications in different fields. According to the definition of nanocomposite, the filler component should be in the range of 10-100 nm. In this study, silver nanoparticles was used as filler with 4 nm size and synthesized by microemulsion method that is known as the best approach for fabricating silver nanoparticles with small sizes, narrow size distribution and high stability.
Copoly (ortho-phenylenediamine/dopamine) was used as matrix component. Ortho-phenylenediamine is one of the conductive polymers that was used less than other conductive polymers such as polyaniline in this research area....
Copoly (ortho-phenylenediamine/dopamine) was used as matrix component. Ortho-phenylenediamine is one of the conductive polymers that was used less than other conductive polymers such as polyaniline in this research area....
Design and Fabrication of Nanocamposite Scaffold for Neural Tissue Engineering
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadat Abadi , Ahmad (Supervisor) ; Neamati, ZiaratAli (Supervisor)
Abstract
Nervous system plays an intricate biological process of man body.Damage of nervous system has serious consequences and is hard to recover, as well as the other parts of the body may not work properly. Many strategies have been used to repair spinal cord injuries in which the main objective is to improve the regeneration of axons and functional recovery. The purpose of this research is introducing neural tissue engineering concepts (e.g. scaffolds, stimulation and etc.) and also design and fabrication suitable for neural tissue engineering. For this purpose the combination of biodegradable polymers (chitosan),conductive polymer (poly-aniline) and carbon nanosheets (graphene) was chosen as the...
Deposition of TiO2/SiO2 Nanocomposite on Cotton Textile by Sol- Gel Method
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
The synthesis and usage of nanoscaled TiO2 accompanied by the photocatalytic activity were experimented through a systematic research. The synthesis was based on the sol-gel method at low temperatures and atmospheric pressure. In recent years, many endeavors have been made so as to enhance the efficiency of TiO2 photocatalytic activity. The studies show that the inclusion of SiO2 into the TiO2 can give rise to the photocatalytic activity relevant to the derived composite Nanoparticles with regard to the pure TiO2. In this study, the production of TiO2-SiO2 Nanocomposite layers was proceeded via the sol method and the effect of SiO2 increasing and its amount in the primary solution on the...
Tree-dimensional Free Vibration of Nano-Composite Plates with Arbitrary Geometry within Couple Stress Theory
, M.Sc. Thesis Sharif University of Technology ; Mohammadi Shoja, Hossein (Supervisor)
Abstract
Based on Hamilton’s principle, a three-dimensional semi-analytical method for the analysis of free vibration of a nano-composite plate within the couple stress theory is developed. Computation of dynamic behavior as well as natural frequencies and mode shapes is interested. In this method, the mechanical displacement functions, in each layer, are defined as product of a base function and a three-dimensional polynomial with unknown coefficients. The base functions are defined with respect to the kinematical boundary condition and the domain geometry. The mode shapes will be obtained and the accuracy of the present approach is demonstrated by comparison it in both classical elasticity and...
Preparation, Surface Modification and Application of Nanocomposite Membranes Based on Transition Metals- Dichalcogenide Nanoparticles in Forward Osmosis Desalination Process
, Ph.D. Dissertation Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor) ; Ahadian, Mohammad Mahdi (Supervisor) ; Amini, Mojtaba (Supervisor)
Abstract
Different parts of this research are focused on developing FO membranes and improving their performance. For this purpose, thin film composite (TFC) membranes with fixed composition of polyethersulfone/polyamide (PES/PA) have been used to investigate the effect of nanocomposites containing transition metal dichalcogenides (TMDs) on their performance. The support layer in all cases is PES, which is prepared through the phase inversion process and does not contain any nanofillers. The modification process takes place in the polyamide layer by dispersing the desired nanoparticles in the aqueous monomer solution necessary to form this active layer. Identification and characterization of...
Development of Modified Nanostructures for Fabrication of Polymer Nanocomposite Films for Controlled Atmosphere Food Packaging
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Pircherghi, Gholamreza (Supervisor) ; Mohammadpour, Raheleh (Co-Supervisor)
Abstract
Active packaging is a novel approach that can ensure food safety by removing undesirable compounds such as Oxygen, ethylene, moisture, and microbial contamination from fresh produce's environment and reducing product loss by extending shelf life. Current research on active food packaging materials focuses on using biopolymers such as carbohydrates, proteins, and lipids as alternatives to non-degradable petroleum-based packaging materials. Active nanomaterials are commonly used to impart functionality to packaging materials. However, the lack of functionality limits their industrial application.Therefore, the main objective of this work was to fabricate bioactive nanocomposite films by...
hysical and Chemical Surface Modification of Titanium by Nanostructured Materials, and Biological Characterization for Use in Bone Tissue Implants
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Vossoughi, Manochehr (Supervisor) ; Samadi Kuchaksaraei, Ali (Supervisor)
Abstract
According to human needs and in line with the development of advanced technologies, different biomedical Engineering fields like hard tissue implants are growing rapidly. Despite significant biotechnology Developments in recent years, some problems to the recognition of implants related osseointegration phenomena persist. The deficient osseointegration and implant-associated infections are key issues for the long-term clinical success of titanium and titanium alloy implants, while development of multifunctional surfaces that can simultaneously overcome these problems remains highly challenging. Therefore, the ultimate goal of this paper was to improve bone cell attachment and simultaneously...
Synthesis and in Vitro/in Vivo Evaluation of Bioprinted and Core-Shell Systems Containing Proteoglycan Nanoparticle and Growth Factor for Skin Tissue Regeneration
, Ph.D. Dissertation Sharif University of Technology ; Simchi, Abdolreza (Supervisor) ; Shokrgozar, Mohammad Ali (Supervisor) ; Tamjid, Elnaz (Co-Supervisor)
Abstract
Tissue engineering has the potential to revolutionize our health care system. Conceptually, lost or malfunctioning tissues will be replaced by man-made biological substitutes to restore, maintain, or improve function. Tissue engineering has already shown great promise to contribute to treatments of a myriad of diseases including osteoarthritis, cancer, diabetes, skin burns, cardiovascular conditions and various traumatic injuries. Tissue engineering is a highly multidisciplinary discipline that demands integration of knowledge, tools and skills from biology, chemistry, engineering and medicine. Integrating nano- and microtechnologies into clinically sized implants represents a major...
Impermeability of Oxygen in Passive/Active Polyethylene Nanocomposite Films
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Shojaei, Akbar (Supervisor)
Abstract
In this study, polyethylene films made of LDPE / LLPE / reinforced with mechanical barrier of clay and reactant of iron nanoparticles were made in their optimal combination and necessary improvements were made on them. Investigations show that, independent of volume fraction, the addition of spherical nanoparticles does not have much effect on reducing the polymer matrix’s permeability. In nanocomposites containing cylindrical particles, for considerable reduction of the permeability, over 20 volume percent of nanoparticles it is required, while in platelet nanoparticles, less than 10% vol is sufficient. In clays with modifier concentration above the cation exchange capacity, there is less...
Synthesis and Characterization of Mechanical and Rheological Properties of Interpenetrating Polymer Network Nanocomposite Hydrogels using Nanostructures
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Kabiri, Kourosh (Supervisor) ; Pourjavadi, Ali (Co-Advisor)
Abstract
Hydrogels are kind of polymers that have ability of frequently applications in agriculture, hygienic, drug delivery and etc. suitable mechanical strength is one of the features of this material. If mechanical strength reduces, efficiency of hydrogels in variety of application will decrease. There are several ways for gel strength improvement, such as cyclic structure for example fumarates, surface crosslinking and preparation of interpenetrating polymer networks (IPNs). Making of nanocomposite structure in hydrogels, using nanostructures, can improve physical-mechanical properties, surprisingly. Therefore, combination of interpenetrating polymer network (IPN) and nanocomposite structures can...
Ionic Polymer-Metal Nanocomposite; Multiscale Simulation, Fabrication and Mechanical Characterization
, Ph.D. Dissertation Sharif University of Technology ; Naghdabadi, Reza (Supervisor) ; Irajizad, Azam (Supervisor) ; Ejtehadi, Mohammad Reza (Co-Advisor)
Abstract
Ionic polymer metal nanocomposites (IPMNCs) are among the advance materials which have been widely used recently as smart materials. These nanocomposites, which are made of polymeric layers (Nafion) plated by metallic or non-metallic conductive electrodes, show large deformations under low applied voltages. The advance materials like these nanocomposites have resolved the problems of the conventional actuators and helped in producing accurate systems.
Several methods have been used to predict the behavior of IPMNCs which any of them consider some simplifying assumptions. In these materials physical phenomena happen at the molecular scale and deformations observed at the large scale....
Several methods have been used to predict the behavior of IPMNCs which any of them consider some simplifying assumptions. In these materials physical phenomena happen at the molecular scale and deformations observed at the large scale....
Mechanical Behavior Analysis of Carbon Nanotube-Based Polymer Composites using Multiscale Modeling
, Ph.D. Dissertation Sharif University of Technology ; Naghdabadi, Reza (Supervisor) ; Rafii Tabar, Hashem (Supervisor) ; Bagheri, Reza (Supervisor)
Abstract
In this project, two multiscale modeling procedures have been implemented to study the mechanical behavior of SWCNT/polymer composites. First, a new three-phase molecular structural mechanics/ finite element (MSM/FE) multiscale model has been introduced which consists of three components, i.e. a carbon nanotube, an interphase layer and outer polymer matrix. The nanotube is modeled at the atomistic scale using MSM, whereas the interphase layer and polymer matrix are analyzed by the FE method. Using this model, we have investigated the macroscopic material properties of nanocomposite with and without considering the interphase and compared the results with molecular dynamics (MD) simulations....