- 學位論文
新穎可逆鏈轉移劑控制自由基聚合反應研究
Studies of new reversible chain transfer agents for living radical polymerization
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摘要
本論文開發二種聚合速率快速的新穎硫羰硫基化合物ZCS2CH2CN(1a)，ZCS2CH2Ph(1b)做為可逆鏈轉移劑(reversible addition-fragmentation chain transfer (RAFT)agent)，有效的控制styrene和acrylate系單體(如tert-Butyl acrylate ,tBA)之自由基聚合反應，達到似活性自由基聚合反應，其數目平均分子量與轉化率成正比，且分子量分佈(Mw/Mn)<1.3。又得聚合物PtBA的反應速率較PS為快，可能為tBA的立體效應大，造成反應較快速。另一方面，由於Z基為強的拉電子基團(此部份涉及專利(中華民國專利申請號：92130435)，此拉電子基團在此以Z基表示)，造成RAFTagent(1a),(1b)的聚合反應速率增快許多。又由於此觸媒系統可聚合的單體多樣化，因此成功合成嵌段(block)共聚合的合成技術，嵌段共聚物poly(St-b-tBA)，分子量分佈<1.3。
並列摘要
Two novel thiocarbonylthio compounds (ZCS2CH2CN (1a) and ZCS2CH2Ph (1b)) were developed as reversible addition-fragmentation chain transfer (RAFT) agents for free radical polymerization. These compounds demonstrate an effective control on free radical polymerization of styrene and acrylate monomers (e.g. tert-Butyl acrylate, tBA), and the reaction behaves like living free radical polymerization with a number average molecular weight proportional to conversion and a narrow polydispersity (Mw/Mn < 1.3). The steric effect of the tBA group may result in the higher reaction rate of PtBA polymerization than that of PS polymerization. Z (Taiwan patent pending number: 92130435), a strong electron-drawing group, can modify the activities of the RAFT agents (1a and 1b) and thus promote the polymerization rate.This catalyst system provides a great variety of monomers for polymerization reactions and thus facilitates the manufacture of poly(St-b-tBA) block copolymers with a narrow polydispersity (Mw/Mn < 1.3).
參考文獻
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