Sharif Digital Repository

In this study, the influence of multi wall carbon nanotube on the thermal properties and microstructure of open cell flexible polyurethane (PU) foam was investigated. To do this untreated CNT (named here n-CNT) along with three different highly functionalized CNTs having carboxyl, hydroxyl and amide functional groups, abbreviated here by CNT-COOH, CNT-OH and CNT-NH-COR, respectively, were employed. A series of PU foam with and without CNTs (both treated and untreated ones) were prepared by cast molding. Prior molding, the CNTs (0.1 wt% loading) were first dispersed into the polyol (Mw = 3000 g/mol and OH No. 56) and then the mixture was subsequently added to the isocynate (TDI). The SEM... 

When oil spill take place, it should be removed rapidly. For control of oil pollution, polymeric foams that absorb oil highly, can be used. These foams are polyurethane and polypropylene that float on water and absorb several times their own weight of crude oil. When a thin layer of crude oil remained on water, it couldn’t be separated by chemical and physical methods. In this cases biological methods will be best and suitable. Therefore absorption and biodegradation of oil spill are executed by immobilization of suitable microorganism on polyurethane foam. But current polyurethane foams aren’t biodegradable so this incompetence should be solved. Polyurethane foams compose of two basic... 

Acidic gases separation from hydrocarbon mixtures is very important in natural gas industry. In this study, the separation of CO2 and H2S from CH4 investigates by experimental and molecular dynamics simulation approaches. For achievement to this goal, it is used two polymeric families, as be divided to polyurethanes and PEBAX copolymers. It is used 4 polyurethane membranes as are named PU-1, PU-2, PU-Ether, and PU-Ester from polyurethanes group. Also, it is applied 5 PEBAX commercial membranes have be known PEBAX-2533, PEBAX-4033, PEBAX-5533, PEBAX-4011, and PEBAX-1074. It is compared between simulation and experimental works and found that there is good agreement between... 

Antibacterial coatings are a branch of paints and coatings industry that has a wide application from Clothing and Textiles to Floor and Medical instrument. Different antibacterial agents such as silver, titanium dioxide, zinc oxide, gold, chitosan, Silicon dioxide, Magnesium hydroxide and carbon nanotubes have been used. UV curable coatings are economic and environmentally friendly coatings and they are one of the fastest growing segments in the paint and coatings industry. Many studies have been conducted on UV curable coatings and their properties. Among different resins, The UV curable polyurethane offer properties such as: Excellent hardness, High gloss, good chemical and weather... 

Due to the presence of carbon dioxide and hydrogen sulfide in natural gas outlet of wells, it cannot be sent directly to the municipal pipelines. This study was trying to be select and made membranes for separation of CO2 and H2S from methane. Permeability of methane and carbon dioxide gases through the polyurethane membranes were studied. For this purpose, two commercial polyurethane and synthesized polyurethane with different formulations of the compounds that have been studied so far in the literature were used. Synthesized polyurethane and nano-composite membranes were characterized by using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and Fourier Transfer... 

Present study demonstrated carbon nanoparticles/acrylate-terminated polyurethane composites as promising materials for bone implants applications. Neat polymer and composites containing nanoparticles at different loadings up to 2 wt % were prepared by in situ polymerization method. Morphological analysis exhibited that nanoparticles caused considerable phase separation between soft and hard domains as well as increased crystallinity. Mechanical analysis showed a significant improvement in mechanical properties. Maximum improvement in tensile properties of APUA was observed at 1 wt% loading of ND-HEAMs, namely 175% improvement in modulus. In vitro biocompatibility evaluation via culturing... 

Selection of appropriate coating system is the most important subject in corrosion control of buried pipelines. Corrosion control of buried pipelines is achieved by using a combination of barrier coatings and cathodic protection (CP). Applying barrier coating can decrease the protection current of CP. However, at the coating holidays the pipeline act as cathode generating hydroxyl ion and hydrogen electrochemically. Therefore the selected coating should be compatible with the alkaline condition.This research focuses on evaluating of an epoxy-tar and a urethane-tar based coating. Coatings performance has been tested by accelerated corrosion test methods (i.e. Salt spray according to ASTM... 

Porous medium is a material consisting of a solid matrix with an interconnected void. A polymer is a large molecule composed of many repeated subunits, known as monomers; Polyurethane is a type of polymer which has many uses. The aim of this research project is to investigate the effective factors in polyurethane polymer injection and the behavior of this material during the foaming in cavities with different soil porosities (0.15 < φ < 0.4). Parameters such as thermal boundary conditions and the soil material that could be effective in solidification of polyurethane are analyzed, numerically using FLUENT software. A simplified model for foaming is presented in this study which can be used... 

Membrane Technology is rapidly growing all over the world because of many applications. In all of this applications , use of adhesive ( between membranes and wall ) is necessary. selection of appropriate adhesive for membrane is very important in order to membrane has best performance and lifetime .Adhesives used in membrane technology must have good adhesion and suitable hardness . One of the newest adhesives used in membrane technology is two-component polyurethane adhesive. PU adhesives make strong and durable bond and have good flexibility which is an advantage for membrane technology.MDI isocyanate is used in most of commercial PU adhesives’ formulation. But in this study , modified MDI... 

The corrosion rate of steel (EN 10130 DC-04) in the presence of oleuropein in aqueous corrosive solutions (of different concentrations in 1M and 0.5M hydrochloric acid and also 3.5% sodium chloride) evaluated and results was shown that oleuropein can protect steel surfaces and it acts as good inhibitor. This means that the observations of linear polarization and weight loss experiments showed inhibitor efficiency more than 97% in acidic corrosive medium and above 74% for aqueous solution of 3.5% sodium chloride. Adding oleuropein at different concentrations (i.e. 300 ppm, 700 ppm, and 1000 ppm) to three different types of polymeric paint structures (nitrocellulose alkyd base, acrylic base,... 

Cardiovascular diseases, especially coronary artery disease and coronary heart disease, are the leading cause of death in human communities. After myocardial infarction, known as heart attack, the flow of oxygen to the heart muscle cells is disrupted. It causes the death of cells that leads to structural and functional changes in the heart muscle. Therefore, specialists try to find a way to repair and regenerate the heart muscle after myocardial infarction. Tissue engineering is used to develop substantial alternatives to assist clinical therapies. Recent studies have focused on the construction of scaffolds with various advanced techniques to create guiding channels that mimic the natural... 

The main focus of this project is the fabrication of surface engineering scaffolds based on polyurethane and titanium dioxide. The research's aim is the creation of the synergistic properties of TiO2 and PU as a new strategy for engineering artificial autologous blood vessels. In the first section, PU-TiO2 nanocomposites were synthesized by co-insitu synthesis of nanoparticles and polymer. The nanocomposite films were prepared by solvent casting and thermally induced phase separation methods. Mechanical and biological properties of films were compared with pure PU film. In solvent casting method, the outcomes revealed that the rate of endothelialization of the nanocomposite scaffold after 7... 

In recent years, the use of polyurethane foams has been of interest for many researchers and craftsmen. Polyurethane foams, due to their excellent properties, can be used in important applications such as advanced military industries, insulation and those requiring strength and maneuverability. The aim of this research project is to produce polyurethane / sodium silicate or nano-silica nanocomposites. Prior to the fabrication and synthesis process of polyurethane containing sodium or nano-silica, deposited silica nanoparticles were synthesized using high-rubbed sodium silicate and sulfuric acid, followed by various tests including XRD, FE-SEM and BET to verify It was done. Sodium silicate... 

Due to population growth, the demand for water supply has increased. This need has drawn attention to the use of consumed and treatable water resources. Organic pollutants are a key source of water pollution. On the other hand, petrochemical oil pollution and frequent oil accidents during oil production or maritime transport have become one of the environmental problems.There are different methods for water and oil separation and water purification that in the present project, selective separation can be achieved by using hydrophobic materials and surface roughness and creating surfaces with two properties: superhydrophobic and ultra-oil friendly. This method is also very effective, cheap... 

In this research, Cu-TATAB/Polyurethane (PU) nanocomposite fibers were prepared via electrospinning method in order to increase the overall extraction efficiency. The incorporation of Cu-TATAB, as a metal organic framework (MOF), in the synthesized nanocomposite contributed to the enhanced efficiency. The prepared sorbent was implemented for the thin film microextraction (TFME) of organochlorine species and their determination was subsequently performed by gas chromatography-mass spectrometry (GC-MS). To achieve the maximum efficiency of the synthesized sorbent, the parameters of MOF percentage in nanocomposites, solvent type and volume, desorption time, solution ionic strength and... 

In recent years, the crude oil spills in the oceans and the excessive emission of electromagnetic waves in the living environment have threatened human health. Therefore, different methods have been considered to deal with each of these two threats. Recently, the use of polymeric boron nitride composites in the production of crude oil absorbents and electromagnetic wave shieldings has received attention due to its thermal conductivity, thermal and chemical stability. In the first step of this research, superhydrophobic composites of polyurethane sponges were prepared by boron nitride and electrically conductive nanomaterials that had photothermal and electrothermal properties. The results... 

Biocompatible materials play a fundamental role in the advancement of medical science and provide groundbreaking solutions for tissue engineering and various therapeutic applications. Among these materials, polyurethane acrylate has attracted attention due to its biocompatibility, versatility, and suitability for creating complex medical scaffolds. This research investigates an innovative approach to reinforce polyurethane acrylate by incorporating graphene quantum dots, with the aim of developing advanced scaffolds for tissue engineering. The incorporation of graphene quantum dots is designed to take advantage of their exceptional properties to improve the mechanical strength, thermal...