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polyethylenes
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An Investigation on Mechanical Behavior of Polypropylene/Polyethylene Blend - Calcium Carbonate Nano Composite
,
M.Sc. Thesis
Sharif University of Technology
;
Bagheri, Reza
(Supervisor)
Abstract
Polymer blending has an important role in preparation of materials with suitable properties without synthesizing new polymers. One of these blends is polypropylene (PP)/ polyethylene (PE). PE is added for improving the impact strength and toughness of PP. For improvementof the properties, a compatibilizer is used due to incompatibility of the PP/PE blend. Improving the impact properties is usually related to the reduction in stiffness. Considering the importance of stiffness in many industrial applications, mineral fillers are employed for increasing the stiffness. In this research, the goal has been to manufacture polypropylene-based ternary composite(Polypropylene/ Polyethylene/Nanometric...
PEG-PLA-Polysccharide Injectable Nanogels for Drug Delivery
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor) ; Dadbin, Sousan (Supervisor)
Abstract
In recent years along with time and cost intensive process of developing new and better drugs for diseases like cancer, scientists and researchers are attempting to develop novel drug delivery systems for already existing drugs.The purpose of these novel drug delivery systems such as nanogels is controlling drug release rate as well as delivery to a specific target tissue in order to reduce side effects. One of the most commonly used drugs for cancer treatment is Doxorubicin HCl, commercially known as Adricin. In this project biodegradable and biocompatible polymers PLA and PEG were used to synthesize nanocarriers for Adricin. These nanocarriers were then dispersed in an agar hydrogel. The...
Thermodynamic and Kinetic Study for Production of Micro and Nano Poly(Ethylene Terephthalate) Particles With Supercritical System
, M.Sc. Thesis Sharif University of Technology ; Goodarznia, Iraj (Supervisor)
Abstract
It is well known that poly(ethylene terephthalate) (PET) is a high melting compound which has exceptional value as a fiber and film-making material, and which currently dominates the whole field of linear polyester substances. However, the high viscosity and limited solubility in liquid solvents restrict its processing to powders and hence the range of applications of such a polymer. Traditionally, crushing, mechanical grinding, ball milling and precipitation from solution are methods for producing powders. The first three ones inevitably change the property of materials. The last one is carried out on the basis of the application of an anti-solvent to decrease the solubility of a...
Some Studies on Conjugation of Nanoparticles Fe3O4 (Fe2O3) to PEG for Drug Delivery Systems
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Manouchehr (Supervisor) ; Yaghmaei, Soheila (Supervisor)
Abstract
The main strategy for treating solid cancers is based on the very early diagnosis of a malignant tumor, and in general the smaller the tumor, the greater the likelihood of successful treatment. Magnetic Resonance Imaging (MRI), based on the nuclear magnetic resonance phenomenon, provides the possibility of detecting early malignant tumors with the assistance of appropriate contrast agents. Hence, researchers continue to develop novel magnetic materials to achieve this aim. Superparamagnetic nanoparticles have become the focus of these studies because their superparamagnetic, biocompatible and hydrophilic properties would be revealed after modifying the particle surface by suitable...
Synthesis and Characterization of Silver/Poly (Lactic Acid) Nanocomposite and Effect of Gamma Ray
, M.Sc. Thesis Sharif University of Technology ; Forounchi, Massoud (Supervisor) ; Dadbin, Susan (Supervisor)
Abstract
Nanocomposites of PLA/Ag, PLA/PEG/Ag and PLA/PEG/Oleic acid were synthesized via chemical reduction of AgNO3.The formation of nano-silver particles (Ag-NPs) started in the aqueous phase (using NaBH4 as a reducing agent) followed by transfer of the silver nanoparticles into the organic phase (PLA solution in chloroform) due to the presence of van der waals interactions between the hydroxyl groups of the PLA and the particles charges surrounded in the surface of the Ag-NPs. The nanocomposites films were prepared by the solution casting method. The XRD patterns and UV-Vis spectra of the nanocomposites demonstrated face–centered cubic (fcc) silver crystals and spherical nanoparticles...
Study of the Evolution of Three-dimensional Pore Structure during Sintering of High Density Polyethylene Powders with Different Particle Size and Melt Flow Index
, M.Sc. Thesis Sharif University of Technology ; Pircheraghi, Gholamreza (Supervisor)
Abstract
Recently, macroporous polymers have gained wide acceptance for applications such as filters, membranes, biodegradable scaffolds, retention media, sound mufflers and etc. In this research, by keeping in mind the importance of the pore structure in the functionality of the porous part, three dimensional images of the pore structure during sintering was obtained using an optimized manual serial sectioning technique. Then, using the Euler number as a property of the topology of the pore surface, evolution of the three dimensional pore structure was scrutinized for two types of powders, powder A with a mean particle size of 200 micron and melt flow index of 0.2 (g/10 min) and powder B with a mean...
Improvement of Physical and Mechanical Properties of Poly (Ethylene Terephthalate) (PET) by Incorporating Metal-organic Framework (MOF) Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Molavi, Hossein (Co-Supervisor)
Abstract
Over the past decade, MOFs have been extensively studied due to their very high specific surface area and porous structure. Among a wide range of MOFs, UiO-66 has produced widespread attention for its excellent solvent resistance and high thermal stability. This nanoparticle is formed by 12 coordinates between Zr6O4(OH)4 unit and terephthalic acid ligand, and it seems that the similarity of its organic ligand with one of the PET-forming monomers makes them highly compatible. In this study, for the first time, the role of UiO-66 nanoparticles in improving the amount and rate of crystallization and mechanical and rheological properties of PET was investigated using the melt mixing method. For...
Experimental Investigation of Biodiesel Production from Oils by Transesterification Method Catalyzed by Nano-heterogeneous Catalysts
, M.Sc. Thesis Sharif University of Technology ;
Abstract
Today polyolefin definitely is one of the most applicable polymers in the world. One of these polymers is ultra-high molecular weight polyethylene. Being applicable in a number of high-tech industries such as military service, battery separators, and other areas, expands the usage of these polymers. Electrospinning is one of the molding methods in order to synthesize fiber polymers. Using this method, a great deal of polymer fibers have been prepared. It is worth noting that the device used for olefins should have temperature control and temperature increase ability. The electrospinning device with the temperature control has not been built in the country; therefore, this device has been...
Partitioning of alkaline protease from Bacillus licheniformis (ATCC 21424) using PEG-K2HPO4 aqueous two-phase system
, Article Fluid Phase Equilibria ; Volume 337 , January , 2013 , Pages 1-5 ; 03783812 (ISSN) ; Pazuki, G. R ; Vossoughi, M ; Mirkhani, S. A ; Seifkordi, A. A ; Sharif University of Technology
2013
Abstract
An aqueous two-phase system (ATPS) containing polyethylene glycol (PEG) and potassium phosphate (K2HPO4) was used for partitioning and partial purification of alkaline protease produced by Bacillus licheniformis ATCC 21424. The effect of PEG molar mass, pH and concentration of NaCl salt addition on partition coefficient, yield and purification factor (PF) for ATPS were studied. The highest partition coefficient (5.3) was achieved in an ATPS of 25% (w/w) PEG 10,000 (g/mol) and 10% (w/w) NaCl at pH 9. Cation and anion exchange chromatography was employed for purification of alkaline protease from protein mixture and the yield and PF for enzyme fractions were obtained to make a comparison...
Cell life cycle effects of bare and coated superparamagnetic iron oxide nanoparticles
, Article Toxic Effects of Nanomaterials ; 2012 , Pages 53-66 ; 9781608054213 (ISBN) ; Laurent, S ; Journeay, W. S ; Sharif University of Technology
2012
Abstract
Due to the hopeful potential of nanoparticles in medicine, they have attracted much attention for various applications such as targeted drug/gene delivery, separation or imaging. Interaction of NPs with the biological environment can lead to a wide range of cellular responses. In order to have safe NPs for biomedical applications, the current biocompatibility researches are particularly focused on the severe toxic mechanisms which cause cells death. These mechanisms are apoptosis, autophagy and necrosis, which can also be intricately linked with the cell-life cycle, as there are various check-points and controls in a cell's life cycle to ensure appropriate division processes. Mechanisms by...
Sensor performance of nanostructured TiO2 thin films derived from particulate sol-gel route and polymeric fugitive agents
, Article Sensors and Actuators, B: Chemical ; Volume 124, Issue 1 , 2007 , Pages 74-83 ; 09254005 (ISSN) ; Fray, D. J ; Cordero Cabrera, M. C ; Sharif University of Technology
2007
Abstract
High specific surface area (SSA) nanocrystalline powders and dip-coated TiO2 thin films have been prepared by a particulate sol-gel route with added polymeric fugitive agents (PFAs), namely trehalose dihydrate (THD), polyethylene glycol (PEG6000) and hydroxypropyl cellulose (HPC). One of the highest SSA reported in the literature, obtained without PFA, was achieved (i.e., 181 m2/g), a value that could be increased up to 304 m2/g, 274 m2/g and 200 m2/g for PEG/TiO2, HPC/TiO2 and THD/TiO2 powders, respectively. Furthermore, the crystallite size varied from 1 nm for as-produced powders up to 4 nm for powders heat-treated at 600 °C. Thin films produced under optimised conditions showed excellent...
Adhesion modification of polyethylenes for metallization using radiation-induced grafting of vinyl monomers
, Article Surface and Coatings Technology ; Volume 201, Issue 16-17 , 2007 , Pages 7519-7529 ; 02578972 (ISSN) ; Fathi, R ; Sheikh, N ; Sharif University of Technology
2007
Abstract
The present paper demonstrates the performance of the radiation grafting technique as a chemically based surface pretreatment method to adhesion modification of polyethylene surfaces toward the metallic layer. Gamma irradiation over a dose range of 4-10 kGy is used for grafting of vinyl monomers including acrylamide (AAm) and 1-vinyl-2-pyrrolidone (NVP) onto the surface of three different polyethylenes including low density polyethylene (LDPE) and two kinds of high density polyethylenes, namely HDPE-1 and HDPE-2. The grafting yield is evaluated based on the weight increase of the samples. It is found that the grafting yield is dominated by the crystallinity of the polyethylene, so that lower...
Influence of process variables on biooxidation of ferrous sulfate by an indigenous Acidithiobacillus ferrooxidans. Part II: Bioreactor experiments
, Article Fuel ; Volume 86, Issue 7-8 , 2007 , Pages 993-999 ; 00162361 (ISSN) ; Yaghmaei, S ; Jafari, A ; Sharif University of Technology
2007
Abstract
The oxidation of ferrous iron in solution using Acidithiobacillus ferrooxidans has industrial applications in the regeneration of ferric iron as an oxidant agent for the removal of hydrogen sulfide from waste gases, desulphurization of coal, leaching of non-ferrous metallic sulfides and treatment of acid mine drainage. The aim of this attempt was to increase the biooxidation rate of ferrous sulfate by using immobilized cells. Rate of ferrous iron oxidation was determined in a packed-bed reactor configuration with low density polyethylene (LDPE) particles as support material in order to find the most practical system for scale-up. The present work studies the influence of basic parameters on...
Gas permeability measurement in polyethylene and its copolymer films
, Article Materials and Design ; Volume 28, Issue 9 , 2007 , Pages 2528-2532 ; 02613069 (ISSN) ; Razavi, J ; Mousavi, S. A ; Sharif University of Technology
Elsevier Ltd
2007
Abstract
In this research, low density polyethylene (LDPE) and poly(ethylene-co-vinyl acetate) (EVA) were used as polymeric materials. The methods used to produce LDPE and EVA was film blowing and thermal-dry phase inversion. The amount of permeability, diffusivity and solubility of O2 and CO2 through above polymers were obtained and also the effect of temperature, pressure and film thickness for LDPE was measured. To study film cross-section morphology in EVA, scanning electron microscopy (SEM) was applied. The results showed that the amount of permeability and solubility were decreased by increasing film thickness but diffusivity was increased. However, by increasing temperature, permeability,...
Optimization of uhmwpe/graphene nanocomposite processing using ziegler-natta catalytic system viaresponse surface methodology
, Article Polymer - Plastics Technology and Engineering ; Vol. 53, Issue. 9 , June , 2014 , pp. 969-974 ; ISSN: 03602559 ; Ramazani, S. A. A ; Sharif University of Technology
Abstract
Optimization of operational conditions for the preparation of Ultrahigh-molecular-weight polyethylene (UHMWPE)/Graphene nanocomposites with Ziegler-Natta catalyst was carried out via response surface methodology (RSM). This study deals with the optimization of process variables to optimize the productivity and molecular weight. A three-factor, three-level Box-Behnken design with temperature (X1), monomer pressure (X2), and [Al]/[Ti] molar ratio (X3) as the independent variables were selected for the study. The dependent variables were productivity and molecular weights of the final nanocomposites. It was developed by using the three parameters at three levels including 50, 60, and 70°C for...
Experimental investigation of operating conditions for preparation of PVA-PEG blend membranes using supercritical CO2
, Article Journal of Supercritical Fluids ; Vol. 95 , November , 2014 , pp. 603-609 ; ISSN: 08968446 ; Nejad-Sadeghi, M ; Goodarznia, I ; Sharif University of Technology
Abstract
Poly(vinyl alcohol)-polyethylene glycol, PVA-PEG, blended membrane were prepared using supercritical fluid assisted phase-inversion method, in which scCO2 was used as the anti-solvent. Poly(vinyl alcohol) was utilized as the main polymer, polyethylene glycol as the additive, and dimethyl sulfoxide (DMSO) as the solvent of these polymers. Taguchi method was used to investigate the effect of some operating parameters on the morphology of the membranes. The L16 orthogonal array was selected under the following conditions: pressure (100, 135, 165 and 200 bar), temperature (40, 45, 50 and 55°C) and PEG weight percent (0, 0.33, 0.66, and 1%). Total polymer concentration of solutions in all...
Development of plasma and/or chemically induced graft co-polymerized electrospun poly(vinylidene fluoride) membranes for solute separation
, Article Separation and Purification Technology ; Volume 108 , 2013 , Pages 196-204 ; 13835866 (ISSN) ; Rana, D ; Matsuura, T ; Tabe, S ; Feng, C ; Sharif University of Technology
2013
Abstract
Nanofiber membranes were fabricated by electrospinning poly(vinylidene fluoride). The electrospun nanofiber membranes were further modified by grafting of acrylic acid (AA) and methacrylic acid (MAA) over the surfaces of the membranes. Plasma AA graft was attempted only, and the results indicated the partial membrane pore filling with grafted AA. For MAA grafting, chemically induced polymerization using benzoyl peroxide and hydrogen peroxide was attempted. The combination of plasma and chemically induced MAA graft polymerization was also attempted. The membranes were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and static contact angle (SCA)...
Two nanostructured polymers: Polyaniline nanofibers and new linear-dendritic matrix of poly(citric acid)-block-poly(ethylene glycol) copolymers for environmental monitoring in novel biosensors
, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 62, Issue 7 , Jul , 2013 , Pages 377-383 ; 00914037 (ISSN) ; Vossoughi, M ; Alemzadeh, I ; Naeini, A. T ; Darvish, M ; Sharif University of Technology
2013
Abstract
In this work two phenol biosensors, one based on polyaniline nanofibers (PNFs) and the other based on the newly created and introduced linear-dendritic matrix of poly(citric acid)-block-poly(ethylene glycol) copolymers (PCA-PEG-PCA), were chemically modified with horseradish peroxidase (HRP) enzyme. These phenol biosensors showed an oxidation peak at 0.55 V. The amperometric response for biosensors based on PNFs showed a linear response range from 2.5 × 10-6 to 2.5 × 10-5 mol/L, with a detection limit of 2.5 M phenol. Also, the amperometric response for a biosensor based on PCA-PEG-PCA showed a linear response range from 2.5 × 10-6 to 4 × 10-5 mol/L, with a detection limit of 1.5 M phenol
Iodine-131 radiolabeling of poly ethylene glycol-coated gold nanorods for in vivo imaging
, Article Journal of Labelled Compounds and Radiopharmaceuticals ; Volume 56, Issue 1 , 2013 , Pages 12-16 ; 03624803 (ISSN) ; Yavari, K ; Outokesh, M ; Sadjadi, S ; Ahmadi, S. J ; Sharif University of Technology
2013
Abstract
Gold nanorods (GNRs) can be used in various biomedical applications; however, very little is known about their in vivo tissue distribution by radiolabeling. Here, we have developed a rapid and simple method with high yield and without disturbing their optical properties for radiolabeling of gold rods with iodine-131 in order to track in vivo tissue uptake of GNRs after systemic administration by biodistribution analysis and γ-imaging. Following intravenous injection into rat, PEGylated GNRs have much longer blood circulation times. We have developed a rapid and simple method for radiolabeling of gold rods with iodine-131 in order to track in vivo tissue uptake of gold nanorods after systemic...
Thermal degradation behavior and kinetic analysis of ultra high molecular weight polyethylene based multi-walled carbon nanotube nanocomposites prepared via in-situ polymerization
, Article Journal of Macromolecular Science, Part A: Pure and Applied Chemistry ; Volume 49, Issue 9 , 2012 , Pages 749-757 ; 10601325 (ISSN) ; Saadatabadi, A. R ; Khorasheh, F ; Sharif University of Technology
T&F
2012
Abstract
Thermal degradation behavior of multi-wall carbon nanotubes (MWCNTs)/ultra high molecular weight polyethylene (UHMWPE) nanocomposites, with different nanotubes contents (0.5, 1.5 and 3.5 wt%) prepared via in-situ polymerization technique have been investigated using thermal gravimetric analysis (TGA). TGA spectra revealed that these nanocomposites had enhanced thermal stability and no significant mass loss (<0.4 wt%) occurred up to 350°C. Thermal degradation of these UHMWPE/MWCNT nanocomposites was investigated in terms of parameters such as the onset temperature of degradation (T 10), the decomposition temperature at 50% wt loss (T 50), the degradation temperature of maximum rate of the...