Processing of poly(l-lactid acid) (PLLA) based piezoelectric polymers and its composites for biomedical applicationNikolić, Sofija (Avtor) Spreitzer, Matjaž (Mentor) Marinšek, Marjan (Komentor) PLLAcompositesoxide-based nanomaterialscrystallizationpiezoelectric properties.In this master’s thesis I was focused on optimization of the structure of PLLA films, made by process of hot drawing and forming their composites. PLLA is very important polymer for biomaterials design, characterized by biodegradation and biocompatibility, and one of the rare polymers approved by Federal Agency of Food and Drugs (FDA) and European Medicines Agency (EMA) for biomedical applications. The two selected polymers that were chosen for this research had different molecular weight. One was with higher molecular weight (Mw=500kDa), PLLA (500 kDa) , and one with lower molecular weight (Mw=250kDa), PLLA (250 kDa). I was working on optimization of layer processing including determination of processing parameters, such as optimal melting temperature, compression temperature, stretching temperature and optimal stretching length under applied stress. The main idea was to determine how those parameters affect the layer structure of polymer films. Moreover, I have prepared composites with mentioned polymers as the matrix. An aim was to investigate how different fillers, mainly oxide-based nanomaterials, such as hydroxyapatite and cobalt ferrite doped with various metals (Zn, Ga), affect certain properties of composites. Their influence on crystallization rate, orientation of polymer chains and surface properties was explored. Lastly, the piezoelectric response for both PLLA films and composites was studied. A lot of valuable data has been obtained through this research, including optimal synthesis conditions.20222022-04-11 14:55:11Magistrsko delo/naloga136085sl