Master's Theses

Nowadays, additive manufacturing, also called AM, has been recognized as one of the key elements of the industry 4.0 revolution due to its efficiency in productivity, decentralized production, and fast prototyping. The goal of this study is to investigate the mechanical and structural properties of polyhydroxybutyrate additive blend materials for additive manufacturing especially in medical applications. In prior to that, the blend between polyhydroxybutyrate (PHB) with polyurethane acrylate (PUA) resins have been developed with PHB at concentrations of pure PUA, 6 wt%, 12 wt%, and 18 wt%. The printability of the blend resins was evaluated by using stereolithography (SLA) 3D printing method. Viscosity has a big role in affecting the printability of the 3D printed blend resins. The highest viscosity ratio that could be efficiently fabricated for PHB/PUA blend resins was at 18 wt% concentration which achieved a value of approximately 2172 centipoise (cP). Furthermore, a shift in the microstructure of PUA was discovered from the FESEM assessment, with more voids being detected. Moreover, the crystallinity index (CI) increased from 9.54% to 22.05% due to the rising of PHB content. This highlights the materials' brittleness characteristics, which contribute to the poor tensile and impact performance. Next, a two-way analysis of variance (ANOVA) was used to study the effects of aging time and PHB loading concentration in PHB/PUA blends on the mechanical performance of tensile and impact parameters. Finally, based on analysis that had been done, 12 wt% composition was selected to be fabricated into a 3D finger splint due to its properties which are rigid but also provide flexibility at the same time that suitable in rehabilitation process.

To address the demand for high-performance and compact batteries for portable electronics, 3D printing could be leveraged to enhance the polymer electrolytes performance. This work provides a new fabrication method for gel polymer electrolytes (GPEs) through the integration of stereolithography (SLA) 3D printing into the fabrication process while maintaining the GPEs performance. The GPEs were fabricated by dissolving different lithium perchlorate (LiClO4) concentrations (0-25 wt.%) into polyurethane acrylate (PUA) and dimethylformamide (DMF) solution, printed using the SLA method, and then studied the impact of LiClO4 towards the GPEs performance. The electrical, morphological, and thermal characteristics of the GPEs were characterized through Electrochemical impedance spectroscopy (EIS), Fourier transform infrared (FTIR), X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscope (SEM). The 3D printed GPEs exhibited high ionic conductivity at 1.24×10-3 S cm-1 at low LiClO4 concentration (10 wt.%). The result was in line with the number of free ions and amorphous fraction determined by FTIR deconvolution and XRD respectively as both showed the highest value at 10 wt.% LiClO4. Besides, the addition of LiClO4 into GPEs polymer matrix causes a shift in urethane, ether, and carbonyl functional groups. The 3D GPEs were thermally stable until it reached a temperature of around 300 oC. As 10 wt.% sample was determined to have the best performance, the formulation was used to fabricate 3D structure GPEs to test its printability which is the most important characteristic for 3D printing. The formulation was successfully printed into three different designs; honeycomb, interdigated, and scaffold structures which indicates that the integration of 3D printing into GPEs fabrication was successful. The ability to construct 3D structures of electrolytes is important as it can significantly improve battery performance by providing a larger contact area with electrodes.