Sharif Digital Repository

In the current study, design, fabrication, and characterization of a novel conductive nanocomposite scaffold for nerve tissue engineering applications is reported. For this purpose, the highly conductive polyaniline/graphene nanocomposite (PAG) was synthesized via emulsion polymerization, used for fabrication of conductive chitosan/gelatin/PAG scaffolds, and the effect of PAG amount on the various properties of scaffolds were investigated. The synthesized graphene, polyaniline, and PAG were characterized and the obtained results revealed that partially exfoliated graphene nanosheets and highly conductive PAG with a conductivity of about 12 S.cm-1 and 7 S.cm-1, respectively were obtained. The... 

Hydrophilic polymers are widely used in enhanced oil recovery (EOR) processes to increase water viscosity during polymer flooding. However, these polymers increase the viscosity of injected water in undesirable strands, before reaching considerable positions that make some problems in polymer flooding process such as thermal, mechanical, bacterial degradation, surface absorption and undesirable plugging. In this study, a novel core-shell structure of polyacrylamide as an active polymer and nanoscale coating polystyrene as a shell polymer was designed and prepared to intelligently control mobility ratio in oil reservoirs and overcome weakness and limitations of classical polymer flooding.... 

Polymer flooding can yield considerable increase in percentage recovery. However, there are limitations with the existing polymer flooding technology, such as thermal, mechanical, bacterial degradation, surface absorption and undesirable plugging. A novel nanocore shell structure of polyacrylamide and polystyrene designed and prepared to intellectually control mobility ratio in oil reservoirs and overcome weakness and limitations of classical polymer flooding. Polyacrylamide particles have been obtained using spray drying of dilute solution of polyacrylamide. Then, polystyrene shell has been produced on polyacryamide particles by in-situ polymerization of styrene monomer in hydrophobic... 

The main object of this thesis is production and investigation of polypropylene-fumed silica nanocomposites by using bi-supported Ziegler-natta catalytic system and in-situ polymerization. Magnesium ethoxide and fumed silica were used as supports of catalyst. TiCl4 was accompanied by triisobutyl aluminum(TiBA) and diisobutyl phthalate(DIBP) as electron doner constituting Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were taken place in slurry phase under the argon atmosphere. At the beginning of the polymerization experiment, several type of nanocomposites were made under various conditions(such as different Al/Ti molar ratio) to find optimum condition to... 

Nerve repair plays a very prominent and significant role among the efforts that have been made to integrate the concepts of tissue engineering in strategies to repair almost all parts of the body. This is partly due to the complexity of the nervous anatomy system and its function as well as the inefficiency of conventional repair methods that are based on a component of biomaterials or cells alone. Studies show that electrical stimulation can enhance the nerve regeneration process; so the use of conducting polymers has attracted much attention for the construction of neural tissue engineering scaffolds. In this study, the electrical properties of neurons and the effects of electrical... 

There are so many problems in using of petroleum-based polymers such as their stability in the environment. According to the research carried out on this problem, one of the best ways to overcome this hardship is using of bio-based polymers. The most important bio-based polymer is polylactic acid. The very polymer enjoys the best mechanical properties but it is so expensive that make it impossible to afford. Therefore, in this project, a nano-composite structure of polylactic acid with thermoplastic starch reinforced with nano-particles was produced. After manufacturing, the process of mixture and the best percent for the very mixture for its use in packaging industry were investigated  

The nervous system is the most important communication machine in body which regulates the function of other organs. Peripheral nerves in contrary to central nervous system have the potential for regeneration, but regrowth requires proper environmental conditions and supporting growth factors. Tissue engineered scaffolds create a suitable milieu for disconnected axon to regenerate. The aim of this study in the first stage is the fabrication of nanostructured of conductive polymers (graphene and polyaniline) within a bed of gelatin polymer and then conducting some analyses including conductance, degradation rate and tensile test besides morphological analyses of fibers through SEM and... 

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... 

Since the early 90s, nanotechnology has contributed to several developments in a wide range of Science and industry such as medicine, Physics, Chemistry, Aerospace, electronics and Biology. In recent years, nanotechnology has also made development in the oil and gas industry. The drilling fluid is already one of the most important parts in drilling operation.The physical properties of a mud, rheological properties and minimize fluid invasion into the formation with perfect mudcake are important to assist in optimizing results. Nano-materials as one of the achievements of recent years are effective in achieving these purposes. To obtain the above properties, a variety of polymers as...