Examensarbeten för masterexamen // Master Theses (IMS)

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https://odr.chalmers.se/handle/20.500.12380/38

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Browsar Examensarbeten för masterexamen // Master Theses (IMS) efter Program "Innovative and sustainable chemical engineering (MPISC), MSc"

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    A framework for assessing safety culture
    (2014) Götvall, Johan; Chalmers tekniska högskola / Institutionen för produkt- och produktionsutveckling; Chalmers University of Technology / Department of Product and Production Development
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    Effect of rheology and crystallinity on processing and barrier properties of PHA
    (2023) Siva Kumar, Amit Kumar; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Kádár, Roland; Kádár, Roland
    Plastic pollution is one of the major problems that the world is facing at present. Different industrial sectors contribute to this and the packaging sector is one of the main contributors. According to the statistics, the packaging sector alone contributes to 60% of the total plastic pollution. This creates the need for the packaging industry to become more sustainable and produce more environmentally friendly products. There are various types of packaging products and this thesis is focused on food packaging. In food packaging a plastic layer is used to act as a barrier against, for example, gases, such as oxygen and carbon dioxide, and sunlight, as these can decrease the shelf life of the packaged food. However, the plastic film is produced from fossil-based resources and is not biodegradable. The replacement of the conventional plastic barriers with a bio-based polymer is one possible solution to move towards more sustainable packaging materials. For this purpose, a class of bio-based polymers named polyhydroxyalkanoates (PHAs) have been studied in this project. Four different types of PHAs have been characterized using techniques such as DSC, TGA, and DMA, among others. Rheological characteristics were also studied to improve the PHA processing and coating onto paperboard at a pilot scale. Additionally, water vapor barrier properties of the different PHA samples and PHA-coated paperboard were measured and the effect of PHA molecular weight and crystallinity on these was also assessed. From this study, it was observed that PHA with higher molecular weight showed better performance in terms of mechanical properties and barrier properties. Moreover, PHA crystallinity has also been shown to play an important role in terms of barrier properties alongside molecular weight. Regarding rheological properties, it was verified that PHA with higher molecular weight has higher melt viscosity, which makes the material stable at higher temperatures but at the same time, hinders the production of proper coating onto the paper-board. For a better understanding of how PHA processing through extrusion coating can be improved in practice, further studies are required, for instance, the change of processing parameters and the compounding of PHA with other components/ polymers.
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    Investigating leading process safety indicators - A study performed at Perstorp Oxo Stenungsund
    (2016) Larsson, Frida; Chalmers tekniska högskola / Institutionen för produkt- och produktionsutveckling; Chalmers University of Technology / Department of Product and Production Development
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    Shear-induced orientation and yielding of Cellulose nanocrystal suspensions: A Rheo-PLI study
    Vinodya, Vihangi; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Kádár, Roland; Akas Mishra, Ases; Bek, Marko
    This thesis presents an investigation of the shear-induced orientation and yielding behavior of CNC water suspensions by employing a Rheo-PLI technique. Cellulose is a structural protein found in plants and algae and plants produce them through synthesis.CNC has demonstrated potential in numerous applications due to its properties such as high mechanical strength, higher crystallinity, high aspect ratio, and optical properties. They are usually using in automotive industries,pharmaceutical industry, reinforcements in fillers and much more.The orientation and its microstructure highly impact to optical and mechanical properties. This study includes the preparation of CNC suspensions and analyze their rheological properties from rheological tests combined with polarized light imaging. In this study we combined the rheological tests with the polarized light imaging technique inorder to examine the yielding and shear-induced orientation of CNC structures in their suspension. We have performed hysteresis loop tests to investigate the thixotropic behavior, oscillatory tests to analyze the viscoelastic behavior, creep tests to examine the stability of CNC suspensions, and Yield stress to determine yielding behavior
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    Surface coating on cathode materials for environmental-friendly battery manufacturing
    (2025) Jayakumar, Karthik; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Klement, Uta; Sun, Jinhua
    An increasing need for sustainable energy has put lithium-ion battery in the forefront of the energy race. Traditional batteries cannot meet the energy demands of the future. Moreover, the use of toxic N-Methyl-2-pyrrolidone (NMP) solvent causes high energy consumption, high cost, and environmental concern of the current battery manufacturing process. In order to eliminate the use of NMP solvent during the electrode processing, here the aim of the project is to modify the surface of cathode material and make it favourable for the water-based electrode processing. Considering the stability issue of cathode in water, graphene, which is impermeable to water, was used as coating materials to protect the surface of cathode material. In addition, introducing graphene in the Li-ion battery improves the performance of the battery as it enhances the conductivity and increases the surface area. The graphene-coated cathode materials were characterized by Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA). The preliminary results demonstrated that the graphene coating could improve the cycling stability and increase the capacity of the lithium-ion battery.