Multi‐Arm Star Polyglycerol‐block‐poly(tert‐butyl acrylate) and the Respective Multi‐Arm Poly(acrylic acid) Stars
Multi‐Arm Star Polyglycerol‐block‐poly(tert‐butyl acrylate) and the Respective Multi‐Arm Poly(acrylic acid) Stars
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DOI：
10.1002/macp.200500332
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发表时间：
2006-01
影响因子：
2.5
通讯作者：
Zhong Shen;Yu Chen;Yu Chen;E. Barriau;H. Frey
中科院分区：
文献类型：
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作者：
Zhong Shen;Yu Chen;Yu Chen;E. Barriau;H. Frey
以聚甘油-聚丙烯酸叔丁酯（PG-b-PtBA）为原料，采用原子转移自由基聚合（ATRP）方法，采用核优先的策略，合成了平均臂数分别为17，27，36，66和90的星形多臂星星嵌段共聚物。在过量浓HCl的二氧六环溶液中水解后，叔丁基酯基团完全水解，得到多臂星星型聚电解质聚甘油-嵌段-聚丙烯酸（PG-b-PAA）。超支化大分子引发剂是在超支化聚甘油的基础上，通过与2-溴异丁酰溴的酯化反应制备的。CuBr/PMDETA和CuBr/Me 6 TREN催化剂体系均已用于tBA的ATRP。发现CuBr/PMDETA允许良好的控制。多臂星的多分散指数主要在1.22 ~ 1.4之间，Mn绝对值与计算值基本一致。此外，动力学曲线显示ln（[M] 0 /[M] t）对时间的线性依赖性，证实聚合是受控的。多臂星的臂数与最大转换率之间的关系。
Well-defined multi-arm star block copolymers, polyglycerol-block-poly(tert-butyl acrylate) (PG-b-PtBA), with average arm-numbers of 17, 27, 36, 66 and 90 arms, respectively, have been prepared by atom transfer radical polymerization (ATRP) of tBA in acetone, using a core-first strategy. After hydrolysis with excess concentrated HCl in refluxing dioxane, full hydrolysis of the tert-butyl ester groups was achieved, resulting in multi-arm star polyelectrolytes, polyglycerol-block-poly(acrylic acid) (PG-b-PAA). The hyperbranched macroinitiators employed were prepared on the basis of hyperbranched polyglycerols via esterification with 2-bromoisobutyryl bromide. Both CuBr/PMDETA and CuBr/Me 6 TREN catalyst systems have been employed for ATRP of tBA. CuBr/PMDETA was found to permit good control. Polydispersity indices for the new multi-arm stars were mainly in the range of 1.22 to 1.4, and the absolute M n data were in agreement with the calculated values. Moreover, kinetic curves show a linear dependence of ln([M] 0 /[M] t ) on time, confirming that the polymerizations are controlled. Relationship between arm numbers of the multi-arm stars and maximum conversion achieved.