فهرست مطالب امیرحسین نوارچیان

Traditional anti-corrosion coatings only act as a passive barrier on the metal substrate and have no active protective function if the coating on the surface is damaged. Recent smart anti-corrosion coatings can greatly increase the lifespan of the coating. On the other hand, self-healing technology in polymer coatings is a preventive method to progress of corrosion process on the surface of metals. This technique has been developed in order to prevent the growth and propagation of cracks in the early stages and to repair the damage automatically without external intervention. The increasing trend of published scientific articles shows that the use of anti-corrosion smart polymer coatings with self-healing capability has received much attention. In this type of coatings, corrosion inhibitors and healing agents can be loaded together or separately in spherical or nanofiber micro-carriers. In the case of damage of the coating surface, the anti-corrosion as well as healing processes trigger simultaneously to prevent the corrosion progress of the metal surface. The purpose of this study is to review novel epoxy-based coatings with self-healing and anti-corrosion properties. For this purpose, the self-healing mechanisms, methods of implementation of self-healing materials and anticorrosion agents on the coating have been reviewed and categorized. The use of polymer microcapsules with core-shell structures in the form of spherical particles or electrospun nanofibers in self-healing coating has been described. Various nanofiber systems have been classified in terms of the location of restorative and anticorrosion materials, the type of polymer shell and core materials, the electrospinning methods of nanofibers, and the method of dispersing within the coatings, for simultaneous anti-corrosion and self-healing properties. Finally, the recent studies on the coatings containing conductive and/or green nanofibers have been reviewed.

Dental composites are widely used for dental restorations due to features such as maintaining the beauty of the teeth, non-invasive and conservative nature, and improving the physical and mechanical properties. Dental composites are susceptible to damages such as micro-cracking caused by thermal and mechanical stresses, which can weaken the properties of these materials. In dental composites, the detection of micro-cracks is very difficult and in some cases impossible. In addition, it is not possible to repair these damages in situ by using conventional materials and methods. Therefore, the self-healing ability in dental composites is necessary. In recent years, the spontaneous repair of damages such as micro-cracking in dental composite materials has been developed without any type of human intervention and the replacement of new components. The most common method for the preparation of self-healing dental composites is microencapsulation of healing agent in polymeric shell and dispersion of the prepared microcapsules in the acrylate matrix of dental composite. The self-healing properties of dental composites can be investigated by determining the fracture toughness of composites before and after healing performance using single edge V-notch beam test. In the present study, the studies on self-healing smart dental composites will be reviewed.

Gas separation by polymer-based membranes, has many applications in various fields particularly gas refinery, petrochemical industries and environmental protection. With the growing interests in this technology, a new type of membranes as mixed matrix membranes (MMMs) have been fabricated in order for employing the advantages of both polymeric and inorganic materials, simultaneously. The metal-organic frameworks (MOFs) incorporated in polymer matrix indicated a desirable gas separation performance. In the present study, first, the structure of MOFs, their role in the membrane and gas transfer mechanism is studied. Then, the recent studies on MOFs/polymer MMMs and the effects of factors on their gas separation performance are reviewed.

Polymers are commonly applied in construction of rechargeable lithium-ion batteries (LiBs). The role of polymer on LiB electrochemical performance is discussed in detail. Literature reviews show that the use of various polymers in construction of LiBs is growing especially as electrolyte, electrode binder, current collector and separator. The polymer type significantly affects the electrochemical performance of LiBs including the capacity, cycle life, and thermal and mechanical stability of battery components. Our literature research indicates that the polymer electrolytes are going to be widely used in LiBs due to their safety and good electrochemical performance. Recently, the major studies have focused on finding appropriate alternatives amongst hydrophilic polymers as electrode binders in LiBs with aqueous electrolytes to enhance ion diffusion through developed hydrophilic properties.

Enapsulation is a new technology with many applications in drug delivery, dyes, agriculture and self-healing polymers. Polymethyl methacrylate (PMMA) is one of the polymers that is widely used as shell material in encapsulation. The main approach for materials encapsulation using PMMA as shell is solvent evaporation technique form double water-oil-water emulsion. In the present study, first, the encapsulation of liquid materials with polymeric shell is studied and then the effective factors on the preparation of micro/nanocapsule with PMMA shell will be reviewed.

The three methods of Design of Experiment: Taguchi, Classic and Shainin can solve quality problem, diagnosis the roots of quality problem and make improvement. To use of these methods, we should recognize the strengths and weakness of them. Recognizing notes of these methods by comparison with a case study, we will understand them deeper. In this study three mentioned methods were compared after implementing, by quantitative and conceptual criteria (those criteria were scored by experts. ) The overall results showed that Classic method has priority for implementation. Although Shainin DOE had more flexibility and less complexity than taguchi method, Taguchi method scored more because it made more improvement and needed fewer experiment so it scored more than Shainin DOE.

Investigation and optimization of polymeric nanocomposite properties including gas diffusion and barrier properties requires characterization study at the molecular level. Experimental methods at this scale are time consuming, expensive and in most cases associated with many experimental errors. Simulation approaches including molecular dynamics simulation (MDS) are very appropriate, fast and low expense alternatives for this purpose to study the properties at nanometric length scale. In this article, the structures of polymer-filled nanocomposites are described at molecular level, and the principles of MDS are introduced. Then, the literature is surveyed in the field of MD simulation of gas diffusion through polymer systems and their barrier properties. The softwares used for the study in this area is also introduced, classified and compared. The trend of the number of published papers during the last decade on this subject are finally described and discussed.

In this paper the synthesis of Sodium 2-Acrylamido-2-Methyl PropaneSulfonate (SAMPS) is studied and the influences of reaction parameters on the conversion are investigated using Taguchi experimental design approach. The results showed that among seven parameters including reaction temperature and time, aeration level and mixing rate in the reaction mixture, the addition sequence of initial materials, and finally the purity and the excess amount of sodium carbonate; just the last two factors as well as the reaction temperature have significant effects, respectively on the reaction extent, while the other factors are insignificant. The optimum conditions to attain the highest conversion are the higher purity and 25% excess amount of sodium carbonate, and 16°C for reaction temperature. The SAMPS product is also characterized by Furrier transform infrared (FT-IR), and hydrogen as well as carbon nuclear magnetic resonance (H-NMR and C-NMR). The morphology and the average particle size of the SAMPS product were also obtained as 20.09 mm (in the range of 1-60 mm) using Scanning Electron Microscopy (SEM).

Poly(vinyl acetate) is synthesized via solution polymerization, and then it is converted to poly(vinyl alcohol) by alkaline alcoholysis. The aim of the work study was to investigate statistically the influence of reaction variables in vinyl acetate polymerization, the conversion of this monomer to polymer, degree of branching of acetyl group in poly(vinyl acetate), as well as the molecular weight of poly(vinyl alcohol), using Taguchi experimental design approach. The reaction variables were polymerization time, molar ratio of initiator to monomer, and volume ratio of monomer to solvent. The statistical analysis of variance of the results revealed that all factors have significantly influenced the conversion and degree of branching. Volume ratio of monomer to solvent is the only factor affecting the molecular weight of poly(vinyl alcohol), and has the greatest influence on all responses. By increasing this ratio, the conversion, degree of branching of acetyl group in poly(vinyl acetate), and molecular weight of poly(vinyl alcohol) were increased.

Poly(vinyl chloride)-clay nanocomposites are a new kind of engineering materials with dramatic improvements in physical, mechanical and thermal properties when compared to virgin PVC or its conventional filled composites. This is due to homogeneous nano-scale dispersion of layered silicates of montmorillonite (MMT) of clay in polymer matrix. In this review paper, the preparation methods of these nanocomposites are categorized. The nanostructure, thermal stability and mechanical properties of PVC-MMT nanocomposites are comprehensively studied and compared with pure PVC. The effect of clay and plasticizer content, and type of compatiblizer on the above mentioned properties is also reviewed. Since MMT is naturally available, economic, and environmentally friendly, the PVC-MMT nanocomposites are expected to have numerous applications in industrial fields.