Synthesis of porous poly(N-isopropylacrylamide) gel beads by sedimentation polymerization and their morphology
Synthesis of porous poly(N-isopropylacrylamide) gel beads by sedimentation polymerization and their morphology
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DOI：
10.1002/app.25605
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发表时间：
2007-04-15
影响因子：
3
通讯作者：
Sakohara, Shuji
中科院分区：
文献类型：
--
作者：
Iizawa, Takashi;Taketa, Hatsumi;Sakohara, Shuji
以N-异丙基丙烯酰胺（NIPA）水溶液为原料，采用沉降聚合法制备了多孔聚N-异丙基丙烯酰胺（PNIPA）微球。当向单体溶液中加入少量DMF和自由基促进剂时，聚合顺利进行，得到具有非常窄的粒度分布的聚合物珠粒。所得珠粒的溶胀速率随着交联剂含量的增加而增加，并且还受所使用的交联剂类型的影响。当使用高于1摩尔%的N，N ′-亚甲基双丙烯酰胺或3摩尔%的二甘醇二丙烯酸酯（DEGDA）作为交联剂时，所得珠粒在20 ℃的水中经历快速溶胀，在5分钟内达到平衡。典型干燥珠粒的横截面照片显示其具有非常复杂的形态，包括大且不规则的空隙，高度多孔的区域，和无孔区。溶胀速率直接取决于珠粒的形态。具有良好多孔区域的PNIPA珠显示出高溶胀率。虽然从DEGDA生产的PNIPA珠具有发达的多孔结构，但它们能够有效地从稀水溶液中浓缩蓝色葡聚糖。(c)2007 Wiley Periodicals，Inc.
Sedimentation polymerization of aqueous solutions of N-isopropylacrylamide (NIPA) was carried out to prepare porous poly(N-isopropylacrylamide) (PNIPA) beads. When small amounts of DMF and a radical accelerator were added to the monomer solution, the polymerization proceeded smoothly to give polymer beads with a very narrow size distribution. The rate of swelling of the resulting bead increased with increasing crosslinker content and was also affected by the type of crosslinker used. When amounts higher than 1 mol % N,N'-methylenebisacrylamide or 3 mol % diethylene glycol diacrylate (DEGDA) were used as a crosslinker, the resulting beads underwent rapid swelling in water at 20 degrees C, reaching the equilibrium within 5 min. A cross-sectional photograph of a typical dried bead showed that it had a very complex morphology consisting of a large and irregular void, highly porous region, and nonporous region. The swelling rate was directly dependent on the morphology of the beads. PNIPA beads with well-developed porous areas show a high swelling rate. Although PNIPA beads produced from DEGDA had well-developed porous structures, they were able to effectively concentrate blue dextran from the dilute aqueous solution. (c) 2007 Wiley Periodicals, Inc.