本研究探討射出成形製程參數對聚乳酸(Polylactic Acid, PLA)和聚乳酸添加有機蒙脫土複材的機械性質影響，以及PLA分子配向性及密度與拉伸強度的關係，PLA複材以有機蒙脫土(Organic Montmorillonite, OMMT)作為填充材料，並利用矽烷偶合劑(Silane coupling agent)，觀察不同含量的PLA複材(PLA/M)及添加矽烷偶合劑之(PLA/S/M)之機械性質變化，另利用模內熱退火方式提升PLA材料結晶度，並觀察退火前後機械性質與硬度的變化。研究方法首先利用熱重分析儀與熱示差掃描卡量計觀察材料耐熱性與熱性質變化，利用實驗設計找出對不同材料拉伸強度與衝擊強度影響最大的製程參數。從實驗結果得知PLA/M之耐熱性皆優於PLA/S/M。PLA拉伸強度受射出速度影響最大，且拉伸強度與核心層剪切應力隨著射出速度提升而增加，而塑料溫度為影響PLA楊氏模數最重要的因子，而目前測試各因子對PLA衝擊強度值的影響性皆不顯著，另PLA試片的拉伸強度及韌性隨著模內熱退火的時間增加而大幅地降低。PLA/S/M的拉伸性質則優於PLA/M，且含4wt%的OMMT(PLA/S/M4)有最佳之平均拉伸強度為84.85MPa，增幅較純PLA達8.0%，而PLA/M的衝擊強度皆優於PLA/S/M，且PLA/M4有最佳之平均抗衝擊強度0.625J/cm2，增幅較純PLA達54.3%。實驗結果顯示，PLA添加有機蒙脫土，以矽烷偶合劑進行改質，具有良好之分散效果，可調整拉伸強度或衝擊強度，未來研究成果可應用於醫療用之外部固定輔具產品製作。

This study is devoted to investigate the influence of injection molding process and analysis on mechanical properties of Polylactic Acid (PLA) and PLA composites with Organic Montmorillonite (OMMT). The relation between molecular orientation, density and tensile strength of PLA have been studied and tested. The OMMT is used as a filler material, and silane is selected as a coupling agent for improving the interface between PLA and OMMT. Design of experiment is adopted to find the most significant factor for tensile strength and impact strength, and to observe effect of different mixing ratio of PLA/M and PLA/S/M of adding silane coupling agent OMMT for improving mechanical properties of specimens. The PLA specimens can increase crystallinity by in-mold annealing process, thus the mechanical properties and hardness change before and after annealing. The thermogravimetry analyzer (TGA) and differential scanning calorimetry (DSC) are used to measure the thermal properties of PLA and PLA composites. Results show that the degree of heat resistance of PLA/M are superior to that of PLA/S/M. From experimental results, injection velocity is the most significant factor for the tensile strength of PLA. Tensile strength and shear stress of core layer have increased as increasing injection velocity. The melt temperature is the most important parameter for Young’s modulus value of PLA. The impact strength of PLA is not found significantly related to current set-up of experiments. Tensile strength and toughness of PLA specimens are significantly reduced with longer in-mold annealing time. The tensile properties of PLA/S/M are superior to that of PLA/M, the PLA/S/M4 of 4wt% OMMT has the largest average tensile strength as 84.85MPa, it increases 8.0% higher than that of pure PLA. The impact strength of PLA/M are superior to that of PLA/S/M. The PLA/M4 has the highest average impact strength as 0.625J/cm2, it increases as 54.3% higher than that of pure PLA. Result of this study can be applied on in-vivo medical or scaffold products by injection molding of PLA composites.

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