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Investigation of Plasticizing and Slump Retaining Properties of
PEG-Based Tri-Block Copolymers in Cementitious Systems
,
M.Sc. Thesis
Sharif University of Technology
;
Pourjavadi, Ali
(Supervisor)
Abstract
Plasticizers in cementitious systems are additives that upon addition at a low dosage can change the workability, mechanical strength and other properties of cement paste effectively. In this study, tri-block copolymers based on poly ethylene glycol (PEG) was synthesised and their applications in the cementitious systems investigated. The main purpose is the verification of plasticizing effects of these copolymers in the cement paste. ABA tri-block copolymers with PEG (1000 and 1500 g/mol) as B block, poly caprolactone, poly caprolactam, poly lactide and poly glycolide (with different weight ratio) as A block were synthesised via ring opening polymerization with stannous octanoate as...
Preparation of Conductive and Semi-Conductive Nanocomposites based on Biocompatible Polymers and Investigation of their Conductive, Mechanical and Electrochemical Properties
, Ph.D. Dissertation Sharif University of Technology ; Pourjavadi, Ali (Supervisor)
Abstract
In this study, conductive and semi-conductive nanocomposites based on biocompatible and biodegradable polymers were prepared and their applications in different areas were studied. Considering huge environmental contaminants derived from various industries, biodegradable polymers (synthetic or natural) have attracted more attention in industrial and biological applications. Aside from their eco-friendly properties, there are other advantages such as availability, different chemical structures, uniqe physical properties and capability to improve their characteristics.One way to improve the properties of the biocompatible polymers is fabrication of their composites with different materials to...
Adsorption characteristics of malachite green dye onto novel kappa-carrageenan-g-polyacrylic acid/TiO2-NH2 hydrogel nanocomposite
, Article Journal of the Iranian Chemical Society ; Volume 11, Issue 4 , August 2014 , Pages 1057-1065 ; Doulabi, M ; Doroudian, M ; Sharif University of Technology
August 2014
Abstract
Batch adsorption experiments were carried out for the removal of malachite green (MG) cationic dye from aqueous solution using novel hydrogel nanocomposite that was prepared by graft copolymerization of acrylic acid (AA) onto kappa-carrageenan (κC) biopolymer in the presence of a crosslinking agent, a free radical initiator and aminosilica-functionalized TiO2 nanoparticles (κC-g-PAA/TiO2-NH2). The factors influencing adsorption capacity of the adsorbents such as initial pH value (pH0) of the dye solutions, TiO2-NH2 content (wt%), initial concentration of the dye, amount of adsorbents, and temperature were investigated. The adsorption capacity of hydrogel nanocomposite for MG was compared...
Synthesis of micelles based on chitosan functionalized with gold nanorods as a light sensitive drug delivery vehicle
, Article International Journal of Biological Macromolecules ; Volume 149 , 2020 , Pages 809-818 ; Bagherifard, M ; Doroudian, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
This study aims to design photo-triggered micelles by using a natural base polymer. Chitosan was functionalized with thiourea, and in the next step, it was modified by grafting poly(L-lactide), poly(N-isopropylacrylamide), and poly(acrylamide) in determined ratio to form thermo-sensitive micelles. The sulfur content of chitosan@thiourea was measured about 2%. Grafting of polymers on chitosan was characterized by FT-IR and NMR techniques. The critical micellar concentration was measured by using photo luminescence spectroscopy. The size and surface morphology experiments revealed that average size of micelles is about 14 nm, and the length and width of GNRs are about 65 and 19 nm,...
Preparation of PVA nanocomposites using salep-reduced graphene oxide with enhanced mechanical and biological properties
, Article RSC Advances ; Volume 5, Issue 112 , 2015 , Pages 92428-92437 ; 20462069 (ISSN) ; Pourbadiei, B ; Doroudian, M ; Azari, S ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
Salep, known as a biodegradable polysaccharide, is hydrolyzed and used as both a reducing agent and stabilizer for graphene oxide (GO). The functionalized reduced graphene oxide (f-rGO) is homogenously dispersed in an aqueous solution of poly(vinyl alcohol) (PVA). PVA based hydrogel and film nanocomposites are prepared and proposed as new biomaterials for tissue engineering applications. The mechanical properties of the film nanocomposites are investigated with varying content of f-rGO, glycerol and citric acid as a reinforcing agent, a plasticizer agent and a cross linking agent respectively. For the first time, chemically cross linked PVA hydrogels are synthesized using...
Novel synthesis route for preparation of porous nitrogen-doped carbons from lignocellulosic wastes for high performance supercapacitors
, Article Journal of Alloys and Compounds ; Volume 827 , 2020 ; Abdolmaleki, H ; Doroudian, M ; Hosseini, S. H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Porous nitrogen-doped carbons derived from biomass wastes are considered as promising materials for energy storage devices. Herein, a novel and scalable synthesis route for preparation of these materials from sugarcane bagasse waste is demonstrated. The synthesis process includes a hydrogel intermediate in which delignified bagasse and polyacrylamide networks are interlaced in molecular scale and calcium acetate serves as a hard template within the polymeric chains. After pre-carbonization and chemical activation of the hydrogel, porous nitrogen-doped carbon with high surface area of 1834.3 m2 g−1 and considerable pore volume of 1.03 cm3 g−1 was obtained with nitrogen and oxygen contents of...