Preparation of Porous PVA Nanocomposite Hydrogels Via Gamma Irradiation

, M.Sc. Thesis Sharif University of Technology Sabourian, Parinaz (Author) ; Frounchi, Masoud (Supervisor) ; Dadbin, Susan (Supervisor)

Abstract

In this research, porous polyvinyl¬ alcohol (PVA)/Montmorillonite nanoclay and polyvinyl alcohol/polyvinyl pyrrolidone (PVP)/Montmorillonite nanoclay nanocomposite sponges (foams) were fabricated by freeze-drying method. The foams were crosslinked using gamma irradiation. The pore size and interconnectivity of nanocomposites characterized by scanning electron microscopy (SEM), showed bimodal pore size distribution resulting from preparation method.
SEM micrographs displayed that addition of PVP ( wt% of total solid polymer) to the PVA sponges increased the pore size and interconnectivity, due to the optimal number of hydrogen bonds between functional groups of polymeric matrices....

Preparation of Polyethersulfone/Polyamide (PES/PA)Thin Film Composite Membranes based Modified Nanoclays for Forward Osmosis-Disalination

, M.Sc. Thesis Sharif University of Technology Veisi, Vahab (Author) ; Bagherzadeh, Mojtaba (Supervisor)

Abstract

In this study, two layer nanocomposite membrane of polyethersulfone (support layer) and polyamide (active layer) were prepared for the purpose of desalination of water by forward osmosis method. In order to take more advantage of this membrane, montmorillonite nanoparticles which had been modified by graphene oxide were placed in it. To bind the nanoparticle components together, at first, montmorillonite was functionalized by (3-Aminopropyl) triethoxysilane to increase its nucleophilicity, and for graphene oxide to increase its electrophilicity, thionyl chloride was added. The two compounds were mixed and stirred for 24 hours in the presence of triethylamine base by magnetic stirrer at 30°C...

Experimental Investigation of a Nnanofibrous Membrane Preparation for Dye Removal from Colored Wastewater

, Ph.D. Dissertation Sharif University of Technology Hosseini, Abolhassan (Author) ; Vossoughi, Manouchehr (Supervisor) ; Mahmoodi, Niyaz Mohammad (Supervisor)

Abstract

In this research, an adsorptive affinity membrane has been prepared based on the combination of the nanofiber structure’s intrinsic characteristic in the dye adsorption and its membrane filtration properties. Electrospinning method has been used to prepare chitosan/poly(vinyl alcohol) (PVA) nanofibers. The morphology and properties of the prepared nanofibrous membranes were characterized using Fourier-transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FE-SEM), image processing, atomic force microscopy (AFM), and thermogravimetric analysis (TGA). Also, the major drawback of electrospun nanofibrous membranes (ENMs) is their low mechanical resistance. So,...

Designing Polymeric Biomaterials based on Polysaccharides with Tissue Adhesion and Hemostasis Performance

, M.Sc. Thesis Sharif University of Technology Shokrani, Hanieh (Author) ; Mashayekhan, Shohreh (Supervisor) ; Kordzadeh, Azadeh (Co-Supervisor)

Abstract

Death can be the result of severe bleeding which is associated with the loss of a high amount of blood like what happens in accidents, wars, or operations. Classic methods to stop bleeding are mostly ineffective to decrease the hemostasis time and the volume of the lost blood. A wide variety of products like powders, foams, and hydrogels have been designed and synthesized either from natural or synthetic polymers. However, limitations like weak tissue adhesion, creating a moist environment in the wound site, infection, weak biodegradation, and hemolysis still have remained. Among the existing options to be used as hemostasis agents, polysaccharides can be appropriate considering their great...