Versatile synthesis of end-functionalized thermosensitive poly(2-isopropyl-2-oxazolines)
Versatile synthesis of end-functionalized thermosensitive poly(2-isopropyl-2-oxazolines)
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DOI：
10.1021/ma049677n
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发表时间：
2004-09-07
期刊：
影响因子：
5.5
通讯作者：
Kataoka, K
中科院分区：
文献类型：
--
作者：
Park, JS;Akiyama, Y;Kataoka, K
以2-异丙基-2-恶唑啉为原料，通过阳离子开环聚合，合成了几种端功能化聚（2-异丙基-2-恶唑啉）PiPrOx。以邻苯二甲酸亚胺活化端羟基聚（2-异丙基-2-恶唑啉Me-PiPrOx-OH），再经联氨处理，得到了一端含有一级氨基的聚（2-异丙基-2-恶唑啉Me-PiPrOx-OH）， m值在3600 ~ 9700之间。以3,3-二氧基-1-丙基tosylate为起始物，以2-异丙基-2-恶唑啉为原料，通过阳离子开环聚合制备了带-缩醛和-羟基（缩醛-PiPrOx- oh）的杂远螺旋PiPrOx。在温和条件下（40-45℃）进行长时间聚合，得到分子量（MW）控制良好、分子量分布（MWD）窄的聚合物。通过H-1和C-13核磁共振光谱、离子交换高效液相色谱和MALDI-TOF质量测量对聚合物进行分析表明，所有情况下都实现了接近定量的端功能化。PiPrOx水溶液（10mm PBS (pH 7.4)，含150mm NaCl）的云点温度接近37度，由浊度决定。热敏远旋PiPrOx作为智能材料，包括生物偶联物、水凝胶和药物载体，具有广阔的应用前景。
The synthesis of several end-functionalized poly(2-isopropyl-2-oxazolines) (PiPrOx) has been achieved via cationic ring-opening polymerization of 2-isopropyl-2-oxazoline. Poly(2-isopropyl-2-oxazolines) bearing primary amino groups at one chain end (Me-PiPrOx-NH2, with M. ranging from 3600 to 9700) were obtained by conversion of hydroxyl-terminated poly(2-isopropyl-2-oxazolines) (Me-PiPrOx-OH) via phthalimide activation of the hydroxl groups and subsequent hydrazine treatment. Heterotelechelic PiPrOx carrying an alpha-acetal and an omega-hydroxyl group (acetal-PiPrOx-OH) were prepared via cationic ring-opening polymerization of 2-isopropyl-2-oxazoline initiated with 3,3-diethoxy-1-propyl tosylate. The polymerizations carried out under mild conditions (40-45 degreesC) for extended periods of time yielded polymers of well-controlled molecular weight (MW) and narrow molecular weight distribution (MWD). Analysis of the polymers by H-1 and C-13 NMR spectroscopy, ion-exchange HPLC, and MALDI-TOF mass measurements indicated that nearly quantitative end-functionalization was achieved in all cases. Aqueous PiPrOx solutions (10 mM PBS (pH 7.4) containing 150 mM NaCl) possess a cloud point temperature near 37 degreesC, as determined by turbidity. Thermosensitive telechelic PiPrOx offer promising applications as smart materials including bioconjugates, hydrogels, and drug carriers.