Sharif Digital Repository

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... 

Magnesium and its alloys have been used as biodegradable implements in recent years. However Magnesium implements may corrode in the body before the natural healing process of the damaged tissue. MAO process was studied in order to reduce primary corrosion of Magnesium alloy in Simulated Body Fluid (SBF). MAO coating was created on AZ31 alloy in a nontoxic alkaline-silicate solution at DC current densities of 5, 10, 15 and 20 mA/cm2 for 30 minutes and the current was in form of 20-10-5 mA/cm2 steps that each were applied for 10 minutes. The maximum corrosion resistance was observed for the mentioned step applied current in a 30g/l Sodium Silicate solution. Furthermore the effects of adding... 

The aim of the present research is to analyse feasibility study of manufacturing the disposable (Biodegradable) plant containers in Iran. The population of the research consists of the whole capacity for manufacturing this product and the similar product producers which have been registered in the Ministry of Industry, Mines and Commerce. First, in this research, the environmental and anti-environmental impacts of non-plant Disposable Containers like: plastic, foam, paper and aluminum have been discussed and also their disadvantages have been examined to be compared with advantages of using plant Disposable Containers. Thereafter, collecting the required data about today society and market,... 

Asphaltine particle precipitation may lead to serious problems in petroleum industry; including wellbore transmissibility reduction. One of the proposed remedial methods is to make a use of the microorganisms which are able to consume the heavy hydrocarbon chains.
Hydrophobicity of a cell surface is one of the parameters which greatly affect the microorganism adhesion to water insoluble hydrocarbons, in which results a higher hydrocarbon biodegradation. Consequently as the hydrophobicity of a cell surface increases; the microorganism tendency to bond with the hydrocarbon molecule enhances. The presence of a surface active agent, as an instance a chemical surfactant, will affect the... 

Due to the negative effects of conventional plastics on the environment, especially in the packaging sector, extensive efforts have been put to replace these polymers with biodegradable polymers. Starch is one of the biodegradable polymers which has attracted a lot of attentions because of low cost and good process ability. Native starch has the form of granule and can be processed to a continuous phase after gelatinization in the presence of a plasticizer. The resulting material is a biodegradable plastic-like material called thermoplastic starch (TPS) which is processed using conventional technologies, but suffers from low mechanical properties and high hydrophilicity. Addition of... 

In the present study, the acrylated polyurethane/nanohydroxyapatite (APU/n-HAp) nanocomposites were fabricated for use in bone tissue regeneration. The APU was synthesized based on poly(ε-caprolactone) diol (PCL), aliphatic 1,6- hexamethylene diisocyanate (HDI) and hydroxyethyl methyl acrylate (HEMA). The effect of HAp nanoparticles on the physicochemical properties of APU was evaluated. The APU/n-HAp nanocomposites were characterized using X-ray diffraction (XRD), dynamic mechanical thermal analyses (DMTA), scanning electron microscopy (SEM) and mechanical tests including tensile strength and elongation at break. The increase in physical properties achieved by incorporation of n-HAp... 

Due to their favorable biodegradability, Magnesium and its alloys have always attracted such a lot of research interests for making temporary implants. With the same direction, Mg-4Zn-0.2Ca has recently absorbed lots of research interests, due to its excellent biocompatibility. As the most regarded draw back concerned with this alloy, poor corrosion resistance is frequently discussed. Accordingly, in the present work it has been tried to come over this problem by addition different amount of aluminum, including 1, 3, 5, 7.5, and 10 percent, to this alloy; without causing any negative effect on its biocompatibility, and to present a new alloy composition with modified degradation behavior.... 

Recently, due to the increase of environmental concerns, a significant raise in applying films and packaging containers, pollution produced from petroleum-based plastics packaging and problems arising from the various methods of waste disposal, the researchers have concentrate to replace these materials with biodegradable ones. In this study, a nanocomposite based on alloy matrix of thermoplastic starch and polyethylene which is reinforced with different amounts of Montmorillonitenanoclay has been constructed by the extrusion process. Furthermore, in order to increase the compatibility between the polar and non-polar components in the group of samples, compatibilizer was used and its... 

With the increasing population and expanding urbanization and changing consumption patterns and relative prosperity increases, the amount of waste generated has increased significantly. So the municipal waste management as one of the challenges that lie ahead for municipal and state has become. Therefore, different approaches have been proposed to solve this problem. In the past government used landfill or incineration program for waste management. Given the risks to the environment and human health are two ways to create and large amount of biodegradable solid waste, composting seems to be good approach for waste management. With using the process on an industrial scale by municipalities,... 

In recent years, magnesium and its alloys have been considered as biodegradable implants, but they corrode in the body before natural process of damaged organs recovery is completed. In this investigation PEO operation was used for corrosion control and effect of different parameter such as number of operation steps, electrolyte type, time and operation voltage on coating properties was studied. Scanning electron microscopy was used for investigating of morphology of coats and to determine chemical composition and phase of coats EDS analysis and X-ray diffraction were used. The corrosion resistance of samples were evaluated by potentiodynamic polarization and electrochemical impedance (EIS)... 

In the recent years, the enhancing of utilization of polymeric materials, especially in packaging application, became the serious concern because of the problems of their recycling. One of efficient ways for solving this problem is usage of biodegradable polymers. Thermoplastic starch (TPS) is one the alternative materials which is produced in gelatinization process by plasticizers. However, using of TPS because of its low mechanical properties, poor processability and high water absorption is not applicable and it is necessary to improve that. One of the strategy in order to improving the TPS properties is blending with other polymers, such as polylactic acid (PLA) which the biodegradable... 

Thermodynamic, structural and transport properties of ester-functionalized ionic liquids (ILs), also kwon as biodegradable ILs, were extensively investigated using molecular dynamic simulation. Thermodynamics features of this class of ILs were computed from 1.5 ns simulations. Nanoscale organization of these ILs was evaluated by computing several structural properties. The formations of micelle-like nanostructures were disclosed from the achieved results of structural properties. The obtained results were also confirmed by calculating transport traits. These results suggest that the incorporation of an ester group into the alkyl side chain of the cation promotes the cation–anion interionic... 

In this project, all-cellulose nanocomposites for smart packaging of meat products were synthesized via film casing method. These nanocomposites were aimed to provide visual response to pH change, which occurs due to decay of the meat products. The prepared nanocomposites would be placed inside the packages to be in direct contact with the products and could improve shelf life the products with the help of antibacterial natural extracts incorporated in the samples.Synthesis of the samples started with cellulose nano whiskers synthesis via acid hydrolysis. The prepared nanoparticles were then characterized with XRD, DLS, and Zeta potential analysis. It was shown that a big portion of the... 

Recently, some wound dressings have been designed that are expected to enhance the wound healing process and prevent blood bleeding and infection. Polymeric dressings have attracted attention due to their biocompatibility, biodegradability, lack of toxicity, and non-allergenic nature. There is widespread interest in using silk fibroin (SF) for this purpose because of its unique properties. Given these points, we have designed an injectable antioxidant hydrogel wound dressing based on SF and Polydopamine(PDA) modified ZnO nanoparticles. First, ZnO nanoparticles were doped with Cu and then modified with PDA (ZnCuO@PDA). XRD, FTIR, SEM, and TEM characterizations were carried out to confirm the...