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    Study of Mechanical Properties of PP/r-PET Composite Reinforced with Flax Fiber

    , M.Sc. Thesis Sharif University of Technology Yosefinezhad, Mehdi (Author) ; Shojaei, Akbar (Supervisor) ; Bagheri, Reza (Supervisor)
    Abstract
    Recycling of polymers, with the aim of environmental protection and economical benefits, is important procedure, which is constantly developing. In this study the effect of the incorporation of recycled PET(r-PET) and recycled polypropylene/Flax(r-PP/Flax) to PP at low (20wt %) and medium content (40wt %) of r-PET was investigated. Polymer compounds were prepared by twin screw extruder followed by injection moulding. The effect of r-PP/Flax and r-PET on PP was evaluated using different techniques such as scanning electron microscopy (SEM), differential scanning calorimetery (DSC), rheological behavior, and mechanical properties (tensile modulus, yield strength, and charpy notched impact... 

    Incorporation of Friction Stir Processing Into Fabrication of Surface Composite in Polypropylene

    , M.Sc. Thesis Sharif University of Technology Shohani, Milad (Author) ; Kokabi, Amir hossein (Supervisor) ; Bagheri, Reza (Supervisor)
    Abstract
    Engineering polymers are being increasingly used in a wide number of applications related to tribological properties. Many chemical and physical methods have been utilized to modify polymer surfaces by depositing thin inorganic films. Most of these techniques are based upon the use of high energy sources that ultimately can damage polymer surfaces either chemically or physically. Incorporation of fillers as reinforcing materials significantly changes various properties of thermoplastics. Friction stir processing (FSP) is a tool to modify the surface properties of materials. It has been developed for upper surface modification of metals in recent studies, exclusively by making surface... 

    Preparation and Investigation of Behavior of Silica Nano Composites with TPU/PP

    , M.Sc. Thesis Sharif University of Technology Meshkati, Erfan (Author) ; Ramazani Saadatabadi, Ahmand (Supervisor)
    Abstract
    Blending can be used as one of the ways of producing materials with appropriate properties, which have many relative advantages in comparison with other methods like polymerization. Among the existing blends in the market and scientific areas, blends of polyurethane thermoplastic and polypropylene have been also studied because of its commercial importance and scientific interest. This blending can improve the mechanical properties, friction resistance, improvement of impact strength at low temperatures and improvement of plasticity properties. In this research, blends with different ratios of TPU/PP is produced by melt mixing, and for improving properties of blends, two kinds of nano fumed ... 

    Study on Effect of Chemical Parameters on Mechanical and Morphological Properties of Biodegradable wo Phase Propylene/Starch Blends

    , M.Sc. Thesis Sharif University of Technology Dorri Moghadam, Afsaneh (Author) ; Bagheri, Reza (Supervisor)
    Abstract
    In recent years the rapid rise of polymer consumption especially in the form of packaging materials became a real menace for the environment. Polyolefin are some of the most dominant packaging materials and responsible by part of the problems in the disposal of one-trip packaging. One of the possible ways of solving this problem is the introduction of additives increasing their susceptibility to environmental degradation into non-biodegradable polymers. One such additive is starch- the natural, cheap, and easily biodegradable polymer. Starch was already used as a filler or as a blend with polyolefin. Addition of dry starch granules to polyolefin follows the general trend of filler effects on... 

    Evaluation of The Effect of Molecular Weight, Mixing Approach and Compatibilizer on Morphologhy and Mechanical Properties of PP/PA/Clay Nanocomposite

    , M.Sc. Thesis Sharif University of Technology Orshesh, Ziba (Author) ; Bagheri, Reza (Supervisor)
    Abstract
    Polypropylene/clay nanocomposites are considered as a group of widely used nanocomposites in industrial applications due to their desired properties, yet reasonable cost. However, dissimmilar chemical nature of polypropylene and clay do not allow perfect dispersion of silicate layeres in the matrix and thus restricts full advantages of these composites.An earlier investigation in this group considered solving this shortcoming through incorporation of PA6 as an intermediate phase to enhance clay platelets dispersion. The current project follows this route via studing the influence of molecular weight of the PP matrix, compatibilzer and the mixing procedure of the compound. To investigate the... 

    Influence of Microstructure on Mechanical Properties and Fracture Behavior of Hybrid PP/GF/CaCO3 Composites

    , M.Sc. Thesis Sharif University of Technology Tabatabaei Ardakani, Ramin (Author) ; Ekrami, Ali Akbar (Supervisor) ; Bagheri, Reza (Supervisor)
    Abstract
    Homo-polymer of Polypropylene is a commodity thermoplastic with good physical and mechanical properties along with fair recyclability and cost. However, its application is limited in some cases, especially in automotive industry, due to a lack of toughness. One of the approaches for PP toughening is the copolymerization of PP with some ethylene co-monomers. However, existence of elastomers in this kind of polymers causes a decrease in tensile properties. Besides, glass fibers improve tensile properties of homo-and co-PP and decrease toughness of co-polymers but result in an increase for homo-polymers. A rise in expenditure of energy due to increasing the processing temperature and... 

    An Investigation on Mechanical Behavior of Polypropylene/Polyethylene Blend - Calcium Carbonate Nano Composite

    , M.Sc. Thesis Sharif University of Technology Shayesteh Zeraati, Ali (Author) ; Bagheri, Reza (Supervisor)
    Abstract
    Polymer blending has an important role in preparation of materials with suitable properties without synthesizing new polymers. One of these blends is polypropylene (PP)/ polyethylene (PE). PE is added for improving the impact strength and toughness of PP. For improvementof the properties, a compatibilizer is used due to incompatibility of the PP/PE blend. Improving the impact properties is usually related to the reduction in stiffness. Considering the importance of stiffness in many industrial applications, mineral fillers are employed for increasing the stiffness. In this research, the goal has been to manufacture polypropylene-based ternary composite(Polypropylene/ Polyethylene/Nanometric... 

    An Investigation on Mechanical and Physical Properties of PP-Short Jute Fibers Composites

    , M.Sc. Thesis Sharif University of Technology Barakchian, Masoud (Author) ; Bagheri, Reza (Supervisor) ; Seyed Reihani, Morteza (Supervisor)
    Abstract
    In recent years, due to greater attention scientific communities to environment and environmental friendly material, use of natural fibers as reinforcing the polymers has increased significantly. High specific strength, low density, cheap, stiffness and recycled by nature, are including promotional items using natural fibers as reinforcing in the polymer composites. In This study has tried in the first place an appropriate method for producing polypropylene composites reinforced with short jute fibers should be presented and then the physical and mechanical properties of composites will be investigated. Used MAPP and Silane for compatibility took improved between natural jute fibers as a... 

    Experimental and Analytical Investigation of Elastic-Plastic Behavior of Glass Fiber Reinforced Polymer Composites

    , M.Sc. Thesis Sharif University of Technology Sajadi, Banafshe (Author) ; Naghdabadi, Reza (Supervisor) ; Asghari, Mohsen (Supervisor)
    Abstract
    In this thesis, we aim to study the elastic-plastic behavior of short fiber reinforced composites experimentally and analytically. The experimental investigation is applied to glass fiber-polypropylene composites (PP/GF). The samples are produced by injection process with maximum temperature of 190C. Fibers are randomly oriented in this procedure of fabrication. The samples are tested in tension, and the mechanical strength is measured by changes in fiber content. The Young's modulus is also investigated in these experiments.Also in this thesis, an analytical model for calculation of Young’s modulus of fiber reinforced composite materials is proposed. In this analysis a displacement field is... 

    Study of Mechanical Properties of Polypropylene in Local and Global Scales: Effect of Crystalline Structure and Testing Conditions

    , Ph.D. Dissertation Sharif University of Technology Lesan-Khosh Monfared, Rasool (Author) ; Bagheri, Reza (Supervisor) ; Asgari, Sirous (Supervisor) ; Naimi Jmal, Mohammad Reza (Co-Advisor)
    Abstract
    In this study, mechanical properties of neat isotactic polypropylene (iPP) were evaluated on local and global scales. Depth-sensing indentation with nanoscale resolution (nanoindentation) and traditional macromechanical tests were incorporated for this purpose at different temperatures and strain rates. Various morphologies and crystalline structures of iPP was obtained via changing processing conditions in melt state. A certain relation was found between the local and global mechanical properties, i. e. yield stress, modulus of elasticity and hardness. Moreover, developed yield models were evaluated on the local scale. The results showed that while crystal plasticity theory is not valid for... 

    Investigation Properties of Polypropylene/Carbon Nanotube Nanocomposites Prepared via in Situ Polymerization Using Bi-Supported Ziegler Natta Catalyst

    , M.Sc. Thesis Sharif University of Technology Jafari Esfad, Narjes (Author) ; Ramezani Saadatabadi, Ahmad (Supervisor)
    Abstract
    In this research polypropylene/carbon nanotube nano composites were prepared via in situ polymerization using Bi-supported Ziegler-Natta catalytic systems. Magnesium etoxide and Multi wall carbon nanotubes(MWCNT) functionalized by hydroxyl groups were used as supports of catalyst. TiCl4 and TiBA were used as catalyst and co catalyst respectively. After defining the polymerization optimum conditions and considering its parameters constant, nano composites with different carbon nanotube contents were produced by changing the polymerization time. Scanning Electron Microscopy (SEM) images certified very good dispersion of MWCNTs throughout polypropylene matrix. The thermal properties behavior of... 

    Preparation and Characterization of Polyamide6/Polypropylene/Carbon nanotubes and Carbon Black Nanocomposites

    , M.Sc. Thesis Sharif University of Technology Haghighatgou Roudsari, Hoda (Author) ; Shojaei, Akbar (Supervisor) ; Forounchi, Massoud (Supervisor)
    Abstract
    Multiwall carbon nanotubes (MWCNTs) and carbon black (CB) reinforced polypropylene/polyamide6 (75/25) nanocomposites were prepared by melt compounding approach. Polypropylene grafted with maleic anhydride (PP-g-MA) was used as compatibilizer. Different amount of fillers were introduced into the polymer blends. The morphology, mechanical, rheological properties and crystallization behavior of the composites were investigated. Scanning electron microscopy was employed to study the microstructure. Differential scanning calorimetry (DSC) results showed that the addition of MWNT or CB to PP/PA6 blend resultes increase in crystallinity degree of PA6. The fillers were found to be located... 

    Role of Molecular Weight and Molecular Weight Distribution on Weldability and Joint Strength of Polypropylene by Hot Plate Welding

    , M.Sc. Thesis Sharif University of Technology Azhdari, Moein (Author) ; Kokabi, Amir Hossein (Supervisor) ; Bagheri, Reza (Supervisor)
    Abstract
    In this study, role of molecular weight and Molecular Weight Distribution (MWD) on joint strength of polypropylene was investigated by hot plate welding. Standard tensile specimens of three different co-polypropylene with low, medium and high Melt Flow Index (MFI) values (MR230C, 440L and 548R respectively) were injected and welded after cutting. Hot plate welding device was used to join specimens. Melt Flow Index and dynamic rheology tests were employed in order to study the rheological behavior of polymers melt. Furthermore tensile test was done to investigate joint strength of specimens at 150, 175 and 200 ͦ C. It was observed that in constant temperature, increasing viscosity (typically... 

    Preparation and Property Investigation of Propylene/Ethylene/ 1-Butene Co&terpolymers Modified by Nano Graphene Oxid

    , M.Sc. Thesis Sharif University of Technology Dehdab, Ali (Author) ; Ramazani Saadat, Ahmad (Supervisor)
    Abstract
    Propylene Copolymers and terpolymers with small amount of 1-butene& ethylene can greatly improve the properties of polypropylene material such as low temperature toughness, printing performance, transparency, process ability and so on, leading to expanding of its application. Poly(propylene-co-1-butene) performance intensely relies on its composition and chain structure. The copolymerization catalyzed by Ziegler-Natta catalyst, which is a multy-active central system. The Ziegler-Natta catalyst TiCl4/ Mg(OEt)2/ DIBP was used for copolymerization. The microstructure of copolymers were characterized by FTIR. The influence of different comonomer ratios on the copolymerization has been... 

    Density and Level Monitoring and Control in Polypropylene Plants

    , M.Sc. Thesis Sharif University of Technology Houshmandian, Esmaeil (Author) ; Hajsadeghi, Khosrow (Supervisor)
    Abstract
    Polypropylene plants receive propylene monomer and produce polypropylene polymer by inducing chemical reactions under high pressure and high temperature conditions. In these plants it is essential to monitor and carefully control the density and level of the material contents in slurry high pressure and high temperature reactors and vessels. Due to process conditions and the advantages of the non contact measuring method we use radioactive level and density measurement method specially gamma ray level and density detectors and transmitters in P.P plants. Sometimes, however known and unknown natural or manmade factors may affect the performance of these devices. The known factors such as NORM... 

    Joining of AA5052 Aluminum to C30S Polypropylene Sheets Using Friction Stir Welding

    , M.Sc. Thesis Sharif University of Technology Shahmiri, Hamid Reza (Author) ; Movahhedi, Mojtaba (Supervisor) ; Kokabi, Amir Hossein (Supervisor)
    Abstract
    Joining metals to polymers is an increasing demand in industry mainly due to weight savings. Polymer-metal hybrid structures are widely used in aerospace and automotive industries. However, dissimilar joining of polymer to metal is very difficult due to large mechanical and physical properties differences. Since conventional methods for joining polymers to metals have various limitations, it is necessary to employ new practical and environmental friendly joining processes. In this study, the feasibility of joining an aluminum alloy (AA5052) to polypropylene (C30S) sheets via friction stir welding was examined. Lap joint configuration was determined as the optimized configuration by analyzing... 

    Casting Method Development and Characteristics Enhancement of High Performance Concrete by Utilization of Nano-SiO2 Particles and Different Types of Fibers

    , Ph.D. Dissertation Sharif University of Technology Mobini, Mohammad Hossein (Author) ; Khaloo, Alireza (Supervisor)
    Abstract
    The aim of this study was to evaluate the effects of applying low replacement ratios (0.75% and 1.50% of the binder weight) of nano-SiO2 particles with different specific surface areas (200 and 380 m2/g) on the properties of high-performance concrete (HPC). Mechanical (compressive and splitting tensile strengths), electrical resistivity, non-destructive (ultrasonic pulse velocity), and microstructural (mercury intrusion porosimetry, X-ray diffraction, and scanning electron microscopy) tests were conducted to investigate the macroscopic and microscopic effects of nano-SiO2 particles on HPC characteristics. The results indicated that the performance of nano-SiO2 particles significantly... 

    Refilled Friction Stir Spot Joining of Aluminum to Polymer Sheets

    , M.Sc. Thesis Sharif University of Technology Karami Pabandi, Hossein (Author) ; Kokabi, Amir Hossein (Supervisor) ; Movahedi, Mojtaba (Supervisor)
    Abstract
    Today, dissimilar joining of metal to polymer is in increasing demand in automotive and aerospace industries. Conventional methods for dissimilar joining of metal to polymer have limitations such as need for complex system and high surface sensitivity. Therefore, in this study, it has been tried to join pre-drilled aluminum sheets to polymer, based on frictional heat and creation of interlocks between the base parts. Refilling the hole is the main advantage of the method. AA5052 sheet with 2 mm thickness and polypropylene reinforced with 3 wt% short-carbon-fiber composite were used as primary materials. The effect of hole diameter in 4 and 5.5 mm and tool rotational speed in 500, 1000, 1500... 

    Optimization of Nanostructure, Mechanical Properties and Flammability of Polypropylene/Nanoclay/Flame Retardant Additive Ternary Compounds

    , M.Sc. Thesis Sharif University of Technology Beyk Khorasani, Mahsa (Author) ; Bagheri, Reza (Supervisor)
    Abstract
    Today, in many industries polypropylene is used as a polyolefin with favorable properties such as chemical resistance, fatigue strength, electrical insulation, as well as good mechanical properties such as high Yang modulus, good toughness, and so on. On the other hand, polyolefins have poor thermal resistance and high flammability. Over the years, many researchers have been working to reduce their flammability through different methods and increase their thermal resistance. Among these methods, adding materials that delayed flammability or stoped it, can be noted. In the industry, these anti-flammable additives are called flame retardants. Flame retardant additives should be selected to... 

    Refining of Nanostructure of Polypropylene/Nanoclay Composite Via Optimization of Compatibilizer and Masterbatch

    , M.Sc. Thesis Sharif University of Technology Jalili, Negin Sadat (Author) ; Bagheri, Reza (Supervisor)
    Abstract
    Polypropylene (PP) is a fast growing polymer, particularly in automotive industry, where PP compounds have replaced many different parts made of conventional materials. In the first step, PP-g-MA, as compatibilizer, was synthesized. Two kinds of polypropylenes including a homo- and a block co-polymer were incorporated for this goal. Characterizations via titration and FTIR tests revealed higher degree of grafting reaction when homo-polymer was used for synthesizing PP-g-MA. In the next step, nanocomposites containing 3 wt% nanoclay with three different PP-g-MA/nanoclay ratios of 1:1, 2:1 and 3:1were made using a co-rotating twin screw extruder. Tensile, impact and XRD tests were performed to...