利用穩定自由基聚合法製備功能性粒子

Synthesis of Functional Particles by Stable Free-radical Polymerization

吳明諭(Ming-Ui Wu)

指導教授 ： 鄭國忠

國立臺北科技大學/工程學院/化學工程所/碩士(2006年)

摘要

本研究利用活性自由基法合成聚4-氯甲基苯乙烯(polychloromethylstyrene, PCMS)與其團連共聚物，並利用三級胺類及尼可丁醇醯胺的改質技術，合成出具氧化還原結構的雙性聚合物，並分析其特性。首先，利用自由基起始劑((benzoyl peroxide,BPO)、穩定自由基(2,2,6,6-tetramethylpiperidinooxy, TEMPO)及4-氯甲基苯乙烯單體(CMS)反應合成聚4-氯甲基苯乙烯(PCMS)，再加入苯乙烯單體(St)合成具有(PCMS-b-PS)，進一步分別利用nicotinamide進行改質，使其形成核部份(core)為疏水性鏈段，殼部份(shell)為親水性的微粒結構。並利用GPC、NMR、EA、SEM、UV、TEM、位相差顯微鏡及動態雷射光散射儀(DLS)等，來探討在不同氧化還原劑、濃度對於雙性團連共聚物形態之影響。
結果顯示，PCMS及PCMS-b-PS團連共聚物的分子量分佈皆能控制在約1.5以下，而改質過後之redox微粒結構的粒徑皆會隨著氧化還原劑、濃度的影響。發現在不同濃度改質下，所形成之微粒粒徑有明顯的變化。此外，在加入還原劑後，可發現到粒子有明顯的沉澱；且更進一步使用吸收光譜儀觀察變化，可發覺到粒子穿透度的變化有逐漸變小的趨勢，說明了加入還原劑後，粒子聚集變大導致穿透度變小，再加入氧化劑(H2O2)後，會發生逆反應導致穿透度的變化有逐漸變大的趨勢，可以證明合成之高分子粒子具有氧化還原特性。另ㄧ方面，利用nicotinamide改質PCMS-b-PS團連共聚物，從q-PCMS和q-PCMS-b-PS互相比較發現，由於q-PCMS-b-PS的改質率為48%較q-PCMS的改質率為69%還低，導致其顆粒聚集較快，穿透度更快變小，靈敏度較高。比較q-PCMS116-b-PS63和q-PCMS116-b-PS197發現，當PS疏水性鏈段較長，會導致添加還原劑後沉澱較為迅速，且發現須添加較多量的氧化劑才會發生逆反應。以三乙基胺改質PCMS-b-PS團連共聚物，從所測的TEM圖中可以看到會有雙層的形狀產生，因此可以推斷改質過後部分為親水段。以螢光劑改質PCMS，從PL測出的結果，其波長在503nm，可以知道改質後高分子發綠光。

關鍵字

活性自由基聚合反應 ； 四級胺化 ； 微粒 ； nicotinamide.

並列摘要

Polychloromethylstyrene, PCMS, macro-initiators were synthesized by a stable free radical polymerizations in the presence of 2,2’,6,6’-teramethyl-1-piperidinyloxy (TEMPO) and benzoyl peroxide initiator; then the TEMPO-capped PCMS were extended by polymerization with styrene monomers to synthesize PCMS-b-PS block copolymers. The homopolymers, PCMS, or the PCMS-b-PS block copolymers were further modified by nicotinamide; then oxidoreduction-sensitive particles were formed. It was found that the particles formed by either homopolymers or block copolymers could be dispersed well in the oxidized state, but were precipitated in the reduced state; then could be reversibly dispersed by adding oxidant, H2O2. The particles formed by the block copolymers showed a more sensitive response than that formed by the homopolymers.

並列關鍵字

living free-radical polymerization ； micelle ； nicotinamide

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