PSI - Issue 43

Komal P. Malla et al. / Procedia Structural Integrity 43 (2023) 71–76 Author name / Structural Integrity Procedia 00 (2022) 000 – 000

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Furthermore, the SEM micrographs after the tensile test (Fig. 3) show that the ductile property of fiber improves with an increase in the filler percentage in polymer blends. Januariyasa et al. (2020) reported similar types of findings in their studies. The increasing filler percentage (> 3 %) increases the surface area of the fiber remarkably and decreases the fiber diameter, which in turn decreases the brittle nature of the fiber and increases the ductile behavior. Fig. 4b illustrates many yielding marks of fibers of the polymer blend, which contains 12 % of filler. Hence, the addition of a certain percentage (6 – 12 %) of nano-HAp as a filler in polymer blends shows a brittle-to ductile transition of fiber microdeformation behavior. Such improvement in the mechanical behavior was not found for the solution cast films, which might be affected by very different sizes (fiber diameter at 6 – 12 % filler: about 0.5 µm, cast film thickness: about 0.3 mm – similar to the thickness of the non-woven mats) and the macrophase separation of the cast films. Therefore, only the electrospun nonwoven mats can be used as scaffolds for bone regeneration due to their morphology and ease of handling. 4. Conclusion The influence of nano-HAp addition on the micromechanical behavior of non-woven fibrous scaffolds made from ternary composite blends of PCL/PLLA/GEL was investigated. The SEM micrographs before and after the tensile test indicated that the fiber's brittle-to-ductile transition was at 0 – 12 percent filler addition. Increasing the percentage of filler in the polymer blends resulted in a significant increase in elastic modulus, tensile strength, and fiber strain at break. As a result, the addition of filler improved the fiber's microdeformation behavior corresponding to a brittle-to-ductile transition (transition from crazing to yielding with increasing filler content). Additionally, electrospun nano-HAp-filled PCL/PLLA/GEL blends using PCL of varied molecular weight have already been prepared (not shown here) and will be characterized in the future. Future research also deals with cell line experiments. Acknowledgements Komal P. Malla thanks University Grants Commission (UGC) Nepal for Ph.D. support grants (Ph.D.74-75/S&T 3) and German Academic Exchange Service for financial support during his stay in Germany. Herbert Jennissen and Goerg Michler acknowledge German Research Foundation for funding of their research project JE 84/15-3 and MI 358/37-3. References Andersson, R. L., Ström, V., Gedde, U. W., Mallon, P. E., Hedenqvist, M. S., Olsson, R. T., 2014, Micromechanics of ultra - toughened electrospun PMMA/PEO fibres as revealed by in - situ tensile testing in an electron microscope. Scientific Reports 4, 6335. Bai, H. W., Huang, C. M., Xiu, H., Gao, Y., Zhang, Q., Fu, Q., 2013, Toughening of poly(L - lactide) with poly( ε - caprolactone): Combined effects of matrix crystallization and impact modifier particle size. Polymer 54, 5257–5266. Ba Linh, N. T., Min, Y. K., Lee, B. T., 2013, Hybrid hydroxyapatite nanoparticles - loaded PCL/GE blend fibers for bone tissue engineering. Journal of Biomaterials Science: Polymer Edition 24, 520–538. Fortelny, I., Ujcic, A., Fambri, L., Slouf, M., 2019, Phase structure, compatibility, and toughness of PLA/PCL blends: A review. Frontiers in Materials 6, 206. Hezma, A. M., El - Rafei, A. M., El - Bahy, G. S., Abdelrazzak, A. B., 2017, Electrospun hydroxyapatite containing polyvinyl alcohol nanofibers doped with nanogold for bone tissue engineering. International Ceramic Review 66, 96–100. Hossan, M. J., Gafur, M. A., Karim, M. M., Rana, A. A., 2015, Mechanical properties of gelatin–hydroxyapatite composite for bone tissue engineering. Bangladesh Journal of Scientific and Industrial Research 50, 15–20. Ito, Y., Hasuda, H., Kamitakahara, M., Ohtsuki, C., Tanihara, M., Kang, I. K., Kwon, O. H., 2005, A composite of hydroxyapatite with electrospun biodegradable nanofibers as a tissue engineering material. Journal of Bioscience and Bioengineering 100, 43–49. Januariyasa, I. K., Ana, I. D., Yusuf, Y., 2020, Nanofibrous poly (vinyl alcohol)/chitosan contained carbonated hydroxyapatite nanoparticles scaffold for bone tissue engineering. Materials Science and Engineering C 107, 110347. Malla, K. P., Henning, S., Lach, R., Jennissen, H., Michler, G. H., Beiner, M., Yadav, R. J., Adhikari, R., 2022, Morphology, deformation, and micromechanical behavior of electrospun nano - hydroxyapatite - blended biohybrid scaffolds. Macromolecular Symposia 403, 2200079. Malla, K. P., Regmi, S., Nepal, A., Bhattarai, S., Yadav, R. J., Sakurai, S., Adhikari, R., 2020, Extraction and characterization of novel natural hydroxyapatite bioceramic by thermal decomposition of waste ostrich bone. International Journal of Biomaterials 2020, 1690178.