TY - THES A1 - Biffo, Fabio T1 - Laser Modification of Thin Polymer Coatings N2 - Traditional manufacturing techniques are well-established for processing polyimides, such as Kapton®. This thesis presents a novel approach to producing polyimide and graphite using low-cost, commercially available equipment. Employing a 450 nm laser to both imidize and pyrolyze a polyamide precursor enables the flexibility of on-site manufacturing, even at a microscale, without relying on conventional fabrication techniques. The proposed method offers significant advantages, including cost and time efficiency, design flexibility, and biocompatibility, paving the way for innovative micromechanical and biomedical sensing applications. Moreover, this technique would enable the integration of fully additive manufacturing methods for Kapton® production, which currently relies primarily on subtractive manufacturing technologies. The thesis outlines the fabrication process, highlights optimal laser settings, and demonstrates the practicality of this technique by developing a water detector sensor manufactured entirely from the precursor liquid using the described method. KW - Polyimide KW - Kapton KW - Laser KW - Addictive Manufacturing KW - 3D Printing Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-21410 ER - TY - THES A1 - Muthyapaga, Sujit Kumar T1 - Enhancing Plastic Degradation in Anaerobic Environments Using Biodigesters and qualitative quantitative analysis of biogas. N2 - Plastic pollution has been one of the significant challenges worldwide. We must develop innovations and recycling technologies with millions of tons of plastic produced annuallyThe amount of plastic waste in landfills, seas, and ecosystems has been seriously degrading the environment. New innovative ideas for reducing plastic waste, such as biodigesters and composting methods, are being utilized worldwide. This research examines options such as anaerobic biodigesters and composting techniques to improve plastic breakdown in controlled atmosphere conditions. In anaerobic digestion, digestion happens with the help of microbial organisms as they help break down the organic materials without oxygen and break down the plastics, simultaneously generating renewable energy resources. This research evaluates polymers developed through a blown film extrusion process at different temperatures, such as Polylactic Acid (PLA), Polybutylene Adipate Terephthalate (PBAT), Polyhydroxybutyrate-co-hydroxy hexanoate(PHBH), Bioplast GF 106, and Ecovio, under anaerobic conditions. The degradation results of polymers after a specific period were analyzed based on their mechanical and chemical properties. The research aimed to assess the rates and effectiveness of plastic decomposition in biodigesters compared to conventional degradation methods while also exploring the viability and scalability of biodigesters for managing plastic waste. This research provides information on the degradation of polymers under anaerobic conditions and how the temperature produced affects their degradation, along with methane production. This information could inform future strategies and regulations focused on decreasing plastic pollution and improving sustainability. KW - PLA KW - PBAT KW - GF 106 KW - Ecovio KW - Plastic degradation KW - Anaerobic digestion KW - Biodigesters KW - SEM KW - FTIR analysis KW - Composting KW - Blown film. Y1 - 2025 ER - TY - THES A1 - Siddireddy, Pradeep Chand T1 - Energy-Efficient Design of Filament Spooling Machines for Sustainable 3D Printing Workflows. N2 - The Thesis encompasses a comprehensive design framework, incorporating detailed calculations for motor selection, tensioning system design, and guide mechanism optimization. The design prioritizes energy efficiency through the implementation of high-efficiency motors, optimized control algorithms, and energy-saving features. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-22408 ER - TY - THES A1 - Jagjit Singh, Humjeet Singh Gill T1 - The effect of shearing in a twin-screw extruder on the mechanical properties of biopolymers (PLA+PBAT) using varied screw designs N2 - The primary aim of this research project was to determine the effects of shearing on the structure of a blend of biopolymers (PLA+PBAT) through tailored screw designs in a twin-screw extruder. To achieve this, 3 different twin intermeshing co-rotating screw designs of an extruder were used. The designs were mainly focused on the kneading and mixing part of the screw which has a shearing effect on the biopolymer. The experiments were carried out by keeping the temperature, screw speed and feed rate constant. To carry out the experiment, a 60:40 blend of PBAT and PLA was utilized. The compounded pellets produced from the 3 screw designs were then used in a Blown Film machine. Furthermore, tensile test was conducted on the resulting samples. The shear strength and strain of the films were calculated. Tear test of the films were additionally carried out to validate the findings. Fourier Transform Infrared (FTIR) test was conducted to study the functional groups, identifying the chemical interactions and phase compatibility of the of PLA&PBAT blend. The results showed that the screw with 3 kneading blocks (HS) and 2 kneading blocks (MS) exhibited almost similar ultimate strength and ultimate strain. The screw design with only conveying elements had lower ultimate strength and strain. The kneading blocks played a role on the mixing and shearing of the biopolymer structure in the blend. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-22950 ER - TY - THES A1 - Achale Arrah Nyama, Bateatey T1 - Development of Sustainable Nanofibre Wound Dressing Using Solution Blow Spinning. N2 - This thesis investigates the production of polylactic acid (PLA) fibrous mats using a low-energy, airbrush-based solution blow spinning (SBS) method with dimethyl carbonate (DMC) as a greener solvent. The study addresses how changes in PLA concentration and air pressure influence fibre formation, fibre diameter distribution, and non-woven mat structure, and examines the implications for incorporating tea tree oil(TTO) and pectin into the resulting materials. PLA solutions in DMC were prepared at multiple concentrations, and the SBS process was evaluated using realistic deposition observations and calculated estimates of material consumption. Fibre morphology was analysed by scanning electron microscopy (SEM), revealing fibrous structures and parameter-dependent differences in diameter distributions and mat heterogeneity. Chemical structure was assessed via FTIR spectroscopy, which indicated that the produced fibre mats were dominated by PLA-characteristic spectral features (and possible DMC contributions), while providing limited evidence for substantial pectin or TTO contributions in the measured spectra under the tested conditions. Thermal analysis (STA) was used to interpret important PLA thermal transitions and to identify possible traces of composites within the fibres. A qualitative hydrophilicity approach based on water droplet wetting behaviour was applied as an initial indicator of surface wettability and potential pectin effects, while recognising its limitations compared to full contact-angle measurements. Overall, the results support SBS with DMC as a viable route to produce PLA fibrous mats and show clear process–structure relationships. However, they also show that better mixing methods and stronger confirmation evidence are needed at every step of the characterisation chain in order for additive incorporation to work. KW - PLA KW - Nanofasern KW - Airbrush-Spinning KW - Wundauflagen KW - Grüne Chemie KW - Dimethylcarbonat KW - Nachhaltige Biomaterialien KW - Antibakterielle Wundauflagen KW - Faserherstellung KW - Polylactic acid KW - Nanofibers KW - Solution blow spinning KW - SBS KW - Low-energy fiber fabrication KW - Wound dressing materials KW - Green solvents KW - Dimethyl carbonate KW - DMC KW - Sustainable biomaterials KW - Antibacterial coatings Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-23107 ER -