Surface modification of thermally expandable microspheres by grafting poly(glycidyl methacrylate) using ARGET ATRP
Surface modification of thermally expandable microspheres by grafting poly(glycidyl methacrylate) using ARGET ATRP
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DOI：
10.1016/j.eurpolymj.2009.05.002
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发表时间：
2009-08-01
影响因子：
6
通讯作者：
Malmstrom, Eva
中科院分区：
文献类型：
--
作者：
Jonsson, Magnus;Nystrom, Daniel;Malmstrom, Eva
本研究采用电子转移(ARGET)再生激活剂接枝甲基丙烯酸缩水甘油酯(GMA)对热膨胀核/壳微球进行表面改性。为了保持膨胀性能，必须将剪切力降至最低，使用与微球兼容的溶剂，并保持较短的反应时间(三个小时或更短)。使用表面带有羟基的微球，发现这些微球转化为α-溴酸酯后，在30℃下只需在甲苯中使用50ppm的铜催化剂，就可以将GMA接枝到GMA上，以PMDETA为配位体，GMA的溶液聚合反应的PDI值达到1.4。当微球存在时，聚合度指数越高，聚合反应就越不受控制。接枝微球的环氧基团在四氢呋喃中被盐酸水解制得亲水性表面。通过热机械分析对每一步反应后的微球的膨胀性能进行了研究，发现微球的膨胀性能得到了很好的保持，对微球的负面影响很小。(C)2009爱思唯尔有限公司。保留所有权利。
This study demonstrates the surface modification of thermally expandable core/shell microspheres by grafting glycidyl methacrylate (GMA) using activators regenerated by electron transfer (ARGET) ATRP. To retain the expansion properties it was essential to minimize the shear forces, use solvents compatible with the microspheres and keep the reaction times short (three hours or less). Using microspheres with hydroxyl groups on the surface, it was found that after converting these to alpha-bromo esters, GMA could be grafted by ARGET ATRP using only 50 ppm of copper catalyst in toluene at 30 degrees C. Decent control of the polymerization was achieved with PMDETA as ligand reaching PDIs of 1.4 for the solution polymerization of GMA. When microspheres were present, the polymerization was less controlled with higher PDIs. The epoxide groups of the grafted microspheres were hydrolyzed by HCl in THF providing a hydrophilic surface of the microsphere. The expansion property of the microspheres was studied after each reaction step by thermal mechanical analysis, and it was found that the expansion capacity was well preserved with only limited negative effect on the microspheres. (C) 2009 Elsevier Ltd. All rights reserved.