碩士 / 國立中興大學 / 森林學系所 / 104 / In this study we utilize sodium alginate, which is easy to obtain and have good biocompatibility to be the shell material of the microcapsules, and use microencapsulation to prepare microcapsules containing essential oil from Calocedrus macrolepis var. formosana, to search for the controlled release capability of the essential oil and provide the application of different product afterward. The experiment apply orifice method to prepare microcapsules, and by changing the concentration of raw material including surfactant, alginate, essential oil and calcium chloride, so we can investigate the average particle size, loading capacity and release properties of microcapsules in different conditions.
Results show that the parameter of microcapsules influences the characteristics of microcapsules. First, the amount of surfactant alters the interfacial tension of solution, the microcapsules will bring out poor formability if there is too much surfactant. The increase of surfactant concentration (> 0.5%) also makes the size of micelles inhomogeneous, but the larger micelles can contain more essential oil so as to cause higher loading encapsulation (approximately 90%). Second, the lower concentration of alginate (0.1%) creates the wider distance of molecular and makes the structure incompletely because it could not form quickly after spraying in calcium chloride solution and goes into the circumstance of gel sheet. On the other hand, The increase of alginate concentration (0.75%) makes the viscosity of emulsion increase, than different magnitude of droplets sprays into the calcium chloride solution lead to the wider particle size of microcapsules (12 -15 and 24 -27 μm). Also, the higher concentration of alginate has much more reaction positions which can react with calcium and bring out the greater density of crosslinking bridge, and get the higher loading encapsulation of essential oil. Furthermore, the amount of essential oil also influences particle size of microcapsules, we can suspect that the increase of essential oil cause the influence of the surfactant to the emulsion, and result in the wider particle size of microcapsules, but there is no significant effect on the loading capacity of microcapsules (> 80% in all test). Third, the increasing concentration of calcium chloride solution will cause the lower particle size of microcapsules. If the concentration of calcium chloride is not enough (< 4%) to be crosslinking with alginate, the part of alginate which isn’t completely hardened would agglomerate with another beside and bring about the wider particle size of microcapsules (3.82-19.7 μm). But the loading capacity of microcapsules wouldn’t be affected in this situation.
On the release experiment, there are different release pattern between two conditions changed. One is when the calcium chloride solution concentration increasing (8%), conditions release oil slowly, the greater density of crosslinking bridge would make the microcapsules structure more stable. The other is that the more essential oil (1 ml) being added into emulsion leads to the shortage thickness of shell material, structure incompletely and faster release oil.
| Identifer | oai:union.ndltd.org:TW/104NCHU5360016 |
| Date | January 2016 |
| Creators | Wen-Hsin Tsou, 鄒文心 |
| Contributors | Yu-Chang Su, 蘇裕昌 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 98 |
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