Assessment of the Effects of Nano <scp>TiO₂</scp> and <scp>HA</scp> Reinforcement Ratio on Mechanical, Morphological, and Thermal Properties of <scp>PLA</scp> Matrix Bio Composites

Although bone tissue has the ability to regenerate itself, this regeneration capacity may be limited in large defects or pathological conditions. The development of biomaterials and tissue scaffolds is of critical importance in supporting bone regeneration. In this context, polymer nanocomposites, which are increasingly gaining interest in bone tissue engineering, benefit from both the flexibility of the polymer and the mechanical strength of inorganic components by dispersing nano-sized fillers in the polymer matrix. This study is important in terms of the multifaceted characterization of the hybrid composite material formed with optimized reinforcement ratios of polylactic acid (PLA), hydroxyapatite (HA), and titanium dioxide (TiO₂) components. The originality of the study stems from the comprehensive examination of the mechanical, morphological, thermal, and biological properties of the material in question and the determination of the optimum reinforcement range in light of data obtained from the studies of different researchers in the literature. This multiparameter and holistic approach contributes to the expansion of the potential application areas of the material and the development of a more in-depth understanding of the field of materials science. This study aims to investigate the thermal, mechanical, and morphological effects of HA and TiO₂ reinforcement and reinforcement ratio on nano PLA matrix material. To synthesize these composites, 10% nano HA and different ratios of nano TiO₂ (1%, 2%, and 3%) were added to the nano PLA matrix material. Specimens were prepared by using the casting particle removal method. For the biocompatibility test of the samples, all composite samples were immersed for 1-4 weeks in simulated body fluid (SBF). For the investigation of mechanical, morphological, and thermal properties, SEM, EDS, XRD, DTA, DCS, TG analyses, and compression tests were performed. As a result, it was observed that the apatite layer on the sample surfaces gradually thickened as the residence time in the SBF increased, and the HA and TiO₂ reinforcement to the matrix material supported the formation of the apatite layer. Also, the highest mass loss was seen in PLA/HA samples. The decomposition temperature of the composites decreased with the addition of HA and TiO₂ to the PLA matrix material. In addition, it has been observed that increasing the TiO₂ reinforcement ratio improves the mechanical properties of the composite and increases its strength.