利用超臨界二氧化碳製備溫度敏感性共聚物

Synthesis of Temperature Sensitive Copolymers In Supercritical Carbon Dioxide

黃綉惠(Siou-Huei Huang)

指導教授 ： 陳延平

國立臺灣大學/工學院/化學工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01236

摘要

近年來，智慧型高分子被廣泛應用於各個研究領域，其中溫度敏感性材料可應用於藥物控制釋放和生物科技材料上，此材料本身若具備生物可分解性，將更增加其應用價值。一般合成方法所使用的有機溶劑、觸媒和起始劑對於環境有較大的衝擊性，並且會造成後續產物分離程序上的困難，因此本研究利用超臨界二氧化碳技術進行此溫度敏感性材料的合成，以降低對環境的危害。
本研究選擇之溫度敏感性單體為N-isopropylacrylamide (NIPAAm)，當其形成聚合物PNIPAAm時，具有約31~32 ℃的低臨界溶解溫度(lower critical solution temperature, LCST)，而當NIPAAm與親水性單體共聚，能提升PNIPAAm的LCST。本研究欲探討不同的親水性單體與NIPAAm共聚時，是否皆能將PNIPAAm的LCST提升至人體溫度(37 ℃)附近，以利於後續藥物包覆材料的應用。
本研究所使用的親水性單體分別為Methacrylic acid(MAA)和N-Methyl-N- vinylacetamide(MVA)，藉由NIPAAm分別與兩親水性單體MAA和MVA共聚合，形成P(NIPAAm-co-MAA)與P(NIPAAm-co-MVA)共聚物，並由FTIR、UV、TGA和SEM等儀器進行分析。首先經由FTIR分析，確認兩共聚物的化學結構，接著由UV分析，發現於純水系統中，只有P(NIPAAm-co-MVA)能將LCST提升至37 ℃左右，而P(NIPAAm-co-MAA)則須在鹼性的環境(pH值為8.67)下，才有提升作用；若將兩共聚物加入交聯劑，則皆能使LCST提升。藉由TGA分析可觀察兩種共聚高分子的熱穩定性，而由SEM圖，可觀察到兩共聚物皆可藉由加入交聯劑，使得粒徑變小；另一方面，P(NIPAAm-co-MAA)會隨著MAA含量增加，使顆粒分散性更好，粒徑亦能變小，可降低至0.068 µm。

關鍵字

超臨界二氧化碳 ； 溫度敏感性 ； 親水性單體 ； 水凝膠 ； 低臨界溶解溫度

並列摘要

In recent years, the intelligent materials with biodegradable have been employed in research and development for the drug delivery and biological processes. Supercritical fluid technology has the advantages of reducing significantly the amount of solvent in traditional process. It can also avoid the oxidation of initiators, and simplify the following separation steps. In this research we synthesize the temperature sensitive materials by using the supercritical carbon dioxide to protect the environment.
Poly(N-isopropylacylamide), PNIPAAm, is a thermoresponsive polymer that has lower critical solution temperature(LCST) around 31~32 ℃ in aqueous solution. In this study, PNIPAAm copolymers with hydrophilic comonomers, Methacrylic acid (MAA) and N-Methyl-N-vinylacetamide (MVA), were synthesized in order to obtain copolymers with LCST slightly higher than the physiological temperature(37 ℃), as required by a drug delivery concept.
The two copolymers, P(NIPAAm-co-MAA) and P(NIPAAm-co-MVA), were examined using FTIR to confirm their chemical structures. In UV analysis, we found that only the LCST of P(NIPAAm-co-MVA) could be promoted to around 37 ℃ in aqueous solution. However the LCST of P(NIPAAm-co-MAA) can be increased in base solution (pH=8.67). In TGA analysis, the thermal stability of copolymers can be observed. In SEM images, We observed that the particle size of two copolymers all became smaller by adding the crosslinkers, and the particle size of P(NIPAAm-co- MAA) can be reduced to 0.068µm by increasing the amount of MAA.

並列關鍵字

supercritical carbon dioxide ； temperature-sensitive ； hydrophilic monomer ； hydrogel ； LCST

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