以逆微乳膠法調控奈微米級碳酸鈣之晶貌

Crystal Morphology Control of Nano-/Micro-sized Calcium Carbonate using Reverse Microemulsion Technique

陳致光(Chih-Kuang Chen)

指導教授 ： 戴怡德

國立臺灣大學/工學院/化學工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01689

摘要

摘要
碳酸鈣為地球上豐富的資源，同時也是工業界使用量最大的無機填充材料，其廣泛的運用於橡塑膠、造紙、塗料、醫藥、封裝材料等行業。碳酸鈣粉體之粒徑、晶貌及晶型為影響基材性能之重要因素。奈米碳酸鈣已被證實可有效的降低填充體積同時提高基材之機械強度，目前市售之奈米碳酸鈣以立方型為主，本研究希望在奈微米尺度下調控粒子晶貌，使碳酸鈣分散在等向性基材中可形成具方向性性質的複合材料，而大幅提升基材之性能。
　　本研究以二逆微乳膠法調控奈微米級碳酸鈣之晶貌，所使用的逆微乳膠系統為AOT/Isooctane/Water，AOT為界面活性劑，Isooctane為油相，水相反應物則分別為氯化鈣與碳酸鈉。我們主要探討逆微乳膠系統中ω值(水/界面活性劑,莫耳比)、S值(水/異辛烷,莫耳比)、無機及有機添加劑效應、總莫耳比(R值)、反應溫度(T值)對碳酸鈣粒徑與晶貌上的影響，同時分析製程再現性及粉體之物理性質。
　　本實驗已成功合成具圓盤片狀、六角片狀、甜甜圈狀、菱形體、紡錘狀、類球狀、雙辦花、條狀、絲狀晶貌之碳酸鈣。類球狀粒徑最小可至100~200nm，圓盤片狀、菱形體、紡錘狀最小可至200~300nm，六角片狀、甜甜圈狀則可控制於1~1.5μm。甜甜圈狀碳酸鈣比表面積高達42m2/g，預期可做為高效能吸收劑。

關鍵字

晶貌 ； 碳酸鈣 ； 逆微乳膠法

並列摘要

Abstract
Calcium carbonate, one of the most abundant resources on earth, which is massively used for inorganic filler in various industrial fields, including rubber, plastic, painting, pharmacy, seal etc.. Particle size, particle morphology and crystal morphology of calcium carbonate affect the performance of matrix materials strongly. Nano-sized calcium carbonate has been proved to reduce its usage and to improve the mechanical strength of matrix materials effectively. Cubic shape is the general form of commercial nano-sized calcium carbonate. The Objective of this study is to control particle morphology of nano-/micro-sized calcium carbonate using the two-reverse-microemulsion technique. Therefore, a composite formed by mixing a matrix with calcium carbonate of distinctive shape may possess high mechanical strength due to the well-aligned structure.
The AOT/isooctane/water reverse microemulsion system was selected in this research. The water phases of the two emulsions are CaCl2 and Na2CO3 aqueous solution, respectively. When the two reverse microemulsions are mixed together, calcium carbonate will precipitate. The effects of several operating variables, including ω values(molar ratio of water/surfactant), S values(molar ratio of water/oil), type and concentration of additives, R values(total molar ratio) and reaction temperature on the particle size and morphology of calcium carbonate were investigated.
This study has successfully synthesized CaCO3 particle with disk, hexagonal plate, rhombohedron, sphere-like, spindle, twin-rosette, doughnut, rods and filament in shapes. The size of the sphere-like particle can be reduced to 100~200nm, of the disk, rhombohedron, and spindle particles,to 200~300nm, of doughnut particle to 1~1.5μm. Doughnut-like particle has a specific surface area as high as 42m2/g, which is expected to be a high-performance absorbent.

並列關鍵字

Calcium carbonate ； particle morphology ； reverse microemulsion

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