本研究研發聚乳酸(Polylactic Acid, PLA)添加58S生物玻璃微球(58S Bioglass Microsphere, 58S BG)複合材料改善微型生物骨支架之力學性質，並依據德國德勒斯登聚合物研究中心(IPF)所設計之新型微型拉伸試片進行模具設計開發，以三因子兩水準的實驗設計(DoE)探討射出成形參數對微觀型態的力學性質。根據實驗設計對熔融溫度(Tmelt) 、射出速度(Vinj)、保壓壓力(Ppack)的參數變異分析，單流向與具縫合線的微型拉伸試片中，由於較低熔融溫度所生成較厚實的凝固表皮層，有助於提升材料整體的機械性質；而添加5-10wt% BG顆粒的PLA複合材料，楊氏模數從13.7 GPa提升至14.0 GPa，但拉伸強度與斷裂伸長量則大幅下降，取決於PLA高分子聚合物與BG顆粒增強材料的界面結合性不足，形成界面不連續複合材料，導致材料受應力的傳遞失效，以及兩相的分離造成孔洞的應力集中，促使材料於缺陷處的提前斷裂，因此在考慮材料機械性質的平衡下，預估3.9wt%BG含量為最佳的混煉比。針對生物醫療應用的評估，模擬人體體液(SBF)被用於測試PLA/BG複合材料的生物活性，並於浸泡7日後，試片表面覆蓋約92.8%的氫氧基磷灰石沉澱物。本研究另透過射出成形成功製備新型PLA/58S BG生物複合材料之生醫產品應用-微型骨螺釘/骨板，並改善PLA基材的力學性質，以及促進與骨組織相互結合之生物活性能力。

The study focuses on developing poly(lactic acid) (PLA) composites with 58S bioglass spheres (58S BG) for improving the mechanical properties of bone tissue engineering scaffolds by injection molding process. The collaboratory research institution, Leibniz Institute of Polymer Research Dresden (IPF), provides a design of new-type microinjection molded tensile rod with and without weld line which can be used to observe the micro features of mechanical properties on PLA composites. The influences of injection molding parameters have been optimized for the mechanical properties according to design of experiment (DoE) with varying injection velocity, melt temperature, and packing pressure. The mechanical behavior of sample with and without weld line have been improved by lowering the melt temperature to obtain in a thicker skin layer. The Young’s modulus of an injected samples increased from 13.7 GPa to 14.0 GPa for adding 5-10wt% 58S BG powder in PLA matrix. However, the tensile strength and elongation at fracture of samples are rapidly falling and convert it to brittle behavior due to the lower bonding properties between polymer and inorganic particle reinforced material bioglass. Therefore, considering the balance of mechanical properties, it is predicted that 3.9wt% BG content is the best mixing ratio. For the biomedical application, the in-vitro bioactivity has been precisely reproduced by apatite-forming ability of biomaterials within 7 days in simulated body fluid (SBF), which the coverage ratio of HA is 98.2% in PLA10wt%BG composites. Thus, novel PLA/58S BG composites have been successfully fabricated into a biomedical product of micro bone screws and plates by microinjection molding, which improves the mechanical properties and the bioactivity for further medical applications.

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