環境敏感型共聚高分子之合成與性質研究 : (I)RAFT法合成溫度/酸鹼雙重應答之三嵌段高分子 (II)磺胺類酸鹼敏感型水膠之合成

Abstract

本研究是利用環境敏感型高分子製備溫度/酸鹼雙重應答之三嵌段共聚高分子與磺胺類酸鹼敏感型水膠。研究中分為兩部份的實驗來探討，第一部分之實驗架構是利用丙烯酸(Acrylic acid,AAc)與氮-異丙基丙烯醯胺 (N-isopropylacrylamide, NIPAAm)共聚合，利用可逆型加成-分裂鏈轉移活性聚合系統(RAFT)合成Poly(AAc-b-NIPAAm-b-AAc)三嵌段共聚物。實驗第二部份，先利用Sulfamethazine(SA)與Methacryloyl chloride反應製備單體Sulfamethazine monomer(SAM)，後續製程分兩部分來討論，分別為磺胺類單體SAM與N,N-二甲基丙烯醯胺(N,N-Dimethylacrylamide,DMAAm)共聚合製備隨機共聚高分子Poly(SAM-DMAAm)及引入熱可交聯單體N-羥甲基丙烯醯胺(N-methylol acrylamide, NMA)共聚合成Poly(SAM-DMAAm-NMA)後進行熱交聯，形成水膠。 實驗的第一部份討論Poly(AAc-b-NIPAAm-b-AAc)共聚高分子中，PAAc與PNIPAAm的比例對整體共聚物之影響。相關重要討論包括共聚物之溫度感應性質(最低臨界溶液溫度LCST)、自組裝微胞的成形條件、粒徑分析、形態觀察和熱性質分析。首先，使用紫外光-可見光分光光譜儀觀察不同酸鹼環境下，高分子水溶液隨著溫度變化的穿透度改變，藉此得到不同組成比例的共聚物之最低臨界溶液溫度(LCST)，再藉由調控溶液的溫度與酸鹼環境來改變鏈段上不同區域的親疏水性。之後，透過動態光散射(DLS)的測試來證實此共聚物之自組裝能力，並於穿透式電子顯微鏡下觀察其自組裝型態的變化，並加以討論。熱性質的部分則是透過熱重量分析儀與熱差式掃描儀去觀察其共聚物組成對熱性質的影響。 實驗第二部份分兩部分討論，第一部份為磺胺類單體SAM與親水性單體DMAAm之共聚物合成與酸鹼敏感性討論。藉由調控單體進料量比去調控其酸鹼敏感性，將其應答酸鹼值控制在pH6.8~7.4，且敏感度介於0.2個pH值之間。第二部份則是引入熱可交聯單體NMA，比較引入NMA交聯前後的酸鹼應答行為，並討論不同的熱交聯溫度與交聯時間對水膠感應性(膨潤-收縮能力)的影響。

In this study, there are two parts of experiments. First part is about the pH/temperature sensitive tri-block copolymer poly(AAc-b-NIPAAm-b-AAc), which is synthesised by RAFT polymerization of acrylic acid and N-isopropylacrylamide .The second part of this research is about the sulfonamide-based pH-sensitive hydrogel, which is synthesized by redox copolymerization of sulfamethazine monomer(SAM) and N,N-Dimethylacrylamide (DMAAm) with the thermo-crosslinkable monomer N-methylol acrylamide(NMA) as crosslinking agent. The first part is the experiment of poly(AAc-b-NIPAAm-b-AAc) copolymer. The main discussion is about the influences of PAAc and PNIPAAm chain segments on tri-block copolymer’s chemical properties and physical properties(ex: temperature- sensitivity of copolymer (lower critical solution temperature LCST)、micelle forming conditions、granulometry、 micelle morphology 、thermal properties). The second part is divided into two sections. The synthesis of pH-sensitive random copolymer poly (SAM-DMAAm) was discussed in first section. By regulating the monomer feed ratio, the starting point of copolymer’s pH-sensitivity can be controlled in the range of pH6.8~pH7.4. Then, the sulfonamide-based pH-sensitive hydrogel was prepared by introducing thermo-crosslinkable monomer NMA to the copolymerization system and going through the thermo-curing process. By comparing the pH-sensitive behaviors of linear random copolymers and hydrogels, the influences of crosslinking effect on the pH-sentivity and on the swelling-shrinkage capacity of hydrogel was discussed in the final section.