利用原子轉移自由基聚合法合成澱粉接枝共聚物

本研究中利用原子轉移自由基聚合法(ATRP)合成澱粉接枝聚甲基丙烯酸甲酯。原子轉移自由基聚合法中需要藉由含有鹵素的起始物起始反應，由於澱粉是醣環結構，所以一開始需先將澱粉進行溴化反應，以得到溴化澱粉。溴化澱粉以FTIR及NMR做結構鑑定，XRD測定結晶結構，以元素分析(EA)量測C、H及O元素含量，並計算出取代度(DS)。從FTIR、NMR、XRD及EA的分析結果可知，澱粉確實與2-溴異丁醯溴反應以得到溴化澱粉，而其溴化取代度為1.68~1.77。 ATRP反應中用溴化澱粉做為起始物、CuBr/PMEDTA做為觸媒系統，使MMA單體接枝聚合，以得到澱粉接枝聚甲基丙烯酸甲酯。研究中會改變反應溫度及觸媒系統比例(starch-Br/CuBr/PMEDTA=1/1/1、1/0.5/0.5)進行討論，利用重量秤差法計算單體轉化率及接枝比值，以FTIR、NMR及XRD作結構鑑定、TGA測定熱裂解溫度、DSC觀察玻璃轉移溫度(Tg)，澱粉接枝共聚物經酸解反應以得到聚甲基丙烯酸甲酯的接枝側鏈，並用GPC測量其分子量與分子量分布。結果發現，70℃與80℃反應的轉化率隨溫度而增加，同樣也會因為觸媒比例高而增加轉化率；然而反應於90℃卻會因為於高溫反應使觸媒分解、溴化澱粉的末端官能基的脫離或是發生solvolysis而導致轉化率下降。利用原子轉移自由基聚合法得到的聚合物其分子量分布範圍於1.0~1.5之間，經酸解得到的接枝PMMA側鏈由GPC測得分子量分布(PDI)範圍在1.40~1.49，位於原子轉移自由基聚合法的分子量分布範圍內。

關鍵字

ATRP ；水溶性澱粉； 2-溴異丁醯溴；聚甲基丙烯酸甲酯

並列摘要

In this research, we used atom transfer radical polymerization method (ATRP) to synthesis starch graft poly(methyl methacrylate). First, starch reacted with the acetyl bromide reaction to obtain the acetyl bromide starch (starch-Br). The chemical structure was indetified by FTIR and NMR, and crystallization structure was determined used XRD. The degree of substitution (DS) was obtained from the results of element analysis (EA). To obtain the starch graft poly(methyl methacrylate), starch-Br was used as initiator, and CuBr/PMEDTA was used as catalyst system. The control conditions contained reaction temperature and the catalyst system proportion (starch-Br/CuBr/PMEDTA =1/1/1、1/0.5/0.5). The chemical structure was analyzed by FTIR and NMR, and the crystallization structure was determined by XRD. The thermal properties such as degradation temperature and glass transition temperature was measured TGA and DSC.

並列關鍵字

ATRP ； soluble starch ； 2-bromo-isobutyryl bromide ； PMMA

參考文獻

Braunecker, W.A. & Matyjaszewski, K. (2007). Controlled/living radical polymerization : Features, developments, and perspectives . Progress in polymer science, 32, 93-146

Matyjaszewski, K. & Xia, J. (2001). Atom Transfer Radical Polymerization. Chemical Reviews, 101, 2921-2990

Edmondson, S., Osborne, V.L. & Huck, W.T.S. (2004). Polymer brushes via surface-initiated polymerizations. Chemical Society Reviews, 33, 14-22

Chiefari, J., Chong, Y.K., Ercole, F., Krstina, J., Jeffery, J., Le, T.P.T., Mayadunne, R.T.A., Meijs, G.F., Moad, C.L., Moad, G. , Rizzardo, E. & Thang, S.H. (1998). Living Free-Radical Polymerization by Reversible Addition-Fragmentation Chain Transfer : The RAFT Process. Macromolecules, 31, 5559-5562

Moad, G., Mayadunne,R.T.A., Rizzardo, E., Skidmore,M. & Thang, S.H. (2003). Synthesis of Novel Architecture by Radical Polymerization with Reversible Addition Fragmentation Chain Transfer (RAFT Polymerization). Macromolecular Symposia, 192, 1-12

國際替代計量

利用原子轉移自由基聚合法合成澱粉接枝共聚物

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