Sharif Digital Repository

The interesting properties of metallic and semiconductor nanowires provide many applications in electronic and optoelectronic devices. In this project, we have synthesized Cu and CdSe nanowires using electrodeposition method. To adjust deposition bath conditions and characterize the structure of deposit first we prepared CdSe thin film on ITO substrates. The used solution was contained 0.1 M CdSO4+ 0.1 mM SeO2 in the acidic situation with pH=2.5. The best reduction potential was determined about -0.5 V. The XPS and XRD analyses showed that the ratio of cadmium to selenium in the films was 1:1 and the film’s structure is amorphous. Optical band gap of the cadmium selenide films was obtained... 

The gas separation properties of polycarbonate (PC) membranes were investigated in this study. These membranes were prepared via dry and dry-wet phase inversion technique. Pure O2, N2, and CO2 gases were permeated through prepared membranes. The effects of membrane preparation conditions, including solvent type, non-solvent type, non-solvent/solvent volumetric ratio, polymer weight fraction, and drying temperature on the gas separation properties of dry PC membranes were investigated using Taguchi experimental design. Taguchi analysis show that polymer weight fraction offers the most important effect on the separation characteristics of the dry PC membranes. To get the highest... 

The interesting properties of metallic nanowires provide many applications in electronic sensors. In this project, we have synthesized Pd nanowires using electrodeposition method. These nanowires are useful for hydrogen sensors by measuring field ionization current in gas. In this project, Pd nanowires were synthesized by electrochemical deposition method in PCT template with 100 nm pore size. The used solution was contained 2mM PdCl2 + 0.1M HCl. The best reduction potential was determined about -0.2V and the best time for synthesizing nanowires was 7 minutes. Chronoampermetric diagrams showed four steps, capacitive current, growth in the holes, reaching to the surface of PCT and the growth... 

Today, membrane bioreactors (MBRs) process is one of the most important options in industrial and municipal wastewater treatment. In MBRs, membrane has an essential influence on their performance. In this study, polycarbonate was exploited as membrane to evaluate its performance in MBR since it has excellent mechanical properties. However, polycarbonate is brittle and breaks at low elongation at room temperature. Solution blending was utilized to improve polycarbonate’s properties. Blending membrane was characterized and assessed by scanning electron microscopy (SEM) and tensile strength. Polycarbonate solution blending with polyurehatne which has excellent toughness and flexibility enhance... 

Epoxy resins have good mechanical and thermal properties, high chemical resistance and low shrinkage during cure but in spite of these good properties,they are brittle and this limits the usage of them. Adding a second, soft or rigid, phase has been always an effective strategy to improve the toughness of epoxy. Rigid phase used in resins are divided into organic and inorganic. The aim of this study is to increase epoxy toughness, maintaining mechanical properties and study effect of silica and polycarbonate on fracture toughness simultaneously. Mechanical properties including yield strength and elastic modulus are evaluated by pressure test. Additionally fracture toughness and three... 

Blend of Polycarbonate/ poly(butylene terephthalate) is among the most famous blends of polycarbonate/polyester with vast engineering applications and unique properties. Miscibility and compatibilization of this blend are important as they directly influence the general properties.Transesterification which occurs in the melt state, is a series of cutting and rejoining of dissimilar polymer chains. The reaction ruins the order of pure chains and forms block copolymers of different natures. Further progress in transesterification lead into a completely random copolymer of initial chains. Time, temperature and addition of catalyst can effectively influence transesterification.In this study,... 

Polycarbonate (PC) is known as one of the engineering plastics with remarkable mechanical properties, but the application of this polymer is limited due to its high notch sensitivity. Blending polycarbonate with other polymers such as acrylonitrile butadiene styrene (ABS) is a method to resolve this disadvantage. PC/ABS blends are commonly used in automotive industry, electrical and electronic devices. As PC and ABS are not completely miscible, a variety of compatibilizers are used to achieve a suitable microstructure and high engineering properties. Considering crucial applications of PC/ABS blends, different flame retardants are also used to reduce the flammability. These flame retardants... 

Nowadays, with the increasing number of polyethylene terephthalate wastes, the issue of its recycling has become very important. Among the problems of polyethylene terephthalate recycling are its loss of crystallinity and mechanical properties. Recycled polyethylene terephthalate does not have the properties of new polyethylene terephthalate and using its mixture with other materials is an effective way to remove its waste from nature and return it to the production cycle. The aim of this study is to produce a mixture of recycled polyethylene terephthalate with polycarbonate and glass fibers with mechanical properties such as good impact strength, which ultimately leads to the production of...