Libraries of statistical hydroxypropyl acrylate containing copolymers with LCST properties prepared by NMP
Libraries of statistical hydroxypropyl acrylate containing copolymers with LCST properties prepared by NMP
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DOI：
10.1021/ma800469p
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发表时间：
2008-07-22
期刊：
影响因子：
5.5
通讯作者：
Schubert, Ulrich S.
中科院分区：
文献类型：
--
作者：
Eggenhuisen, Tamara M.;Becer, C. Remzi;Schubert, Ulrich S.
以N-叔丁基-N-（1 '-二乙基膦酰基-2，2'-二甲基丙基）-O-（2-羧基丙-2-基）烷氧基胺（BlocBuilder）为引发剂，加入游离氮氧自由基（SG-1），研究了氮氧自由基介导的丙烯酸2-羟丙酯（HPA）与N-丙烯酰吗啉（Amor）或N，N-二甲基丙烯酰胺（DMA）的共聚反应。使用Chemspeed ASW 2000自动化平行合成仪测试不同的反应条件，例如另外的SG-1的浓度，以优化均聚。对于所有三种单体的均聚（多分散性指数为1.2-1.3）的最佳控制是在110 ℃的反应温度下使用20%额外的SG-1（相对于引发剂）对于2 M的N，N-二甲基甲酰胺溶液和100/1的单体/引发剂比率实现的。P（Amor-stat-HPA）和P（DMA-stat-HPA）的文库使用对于均聚获得的优化条件用0-100摩尔% HPA以10摩尔%增量合成。所得聚合物具有窄的分子量分布，和它们的组合物，使用H-1 NMR光谱和元素分析，确定接近的理论组成。此外，两个库的所有共聚物都具有单一的玻璃化转变温度（T-g），并且转变温度随着HPA含量的增加从P（Amor）（147 ℃）和P（DMA）（111 ℃）的T-g降低到P（HPA）（22 ℃）的T-g。P（HPA）的浊点具有浓度依赖性和滞后性。对于浓度为1重量%的P（Amor-stat-HPA）和P（DMA-stat-HPA），共聚物库的水溶液的浊点可以分别从21.4 ° C调节至88.0 ° C和82.9 ° C。对于在P（Amor-stat-HPA）中具有>40重量% HPA和在P（DMA-stat-HPA）库中具有>55重量% HPA的共聚物观察到LCST行为。
The nitroxide-mediated copolymerization of 2-hydroxypropyl acrylate (HPA) with N-acryloylmorpholine (Amor) or N,N-dimethylacrylamide (DMA) was investigated using N-tert-butyl-N-(1'-diethylphosphono2,2'-dimethylpropyl)-O-(2-carboxyl-prop-2-yl) (BlocBuilder) alkoxyamine initiator and additional free nitroxide (SG-1). Different reaction conditions, such as the concentration of additional SG-1, were tested to optimize the homopolymerizations using a Chemspeed ASW2000 automated parallel synthesizer. Best control for the hornopolymerizations (polydispersity indices of 1.2-1.3) of all three monomers was achieved using 20% additional SG-1 (relative to the initiator) at a reaction temperature of 110 degrees C for 2 M solutions in N,N-dimethylformamide and a monomer/initiator ratio of 100/1. Libraries of P(Amor-stat-HPA) and P(DMA-stat-HPA) were synthesized with 0-100 mol % HPA with 10 mol % increments using the optimized conditions obtained for the homopolymerizations. The resulting polymers had narrow molecular weight distributions, and their compositions, determined using H-1 NMR spectroscopy and elemental analysis, were close to the theoretical compositions. In addition, all copolymers of both libraries had single glass transition temperatures (T-g), and the transition temperatures decreased from the T-g of P(Amor) (147 degrees C) and P(DMA) (111 degrees C) to the T-g of P(HPA) (22 degrees C) with increasing HPA content. The cloud point of P(HPA) showed concentration dependence as well as a concentration dependent hysteresis. The cloud points of aqueous solutions of the copolymer libraries could be tuned from 21.4 to 88.0 degrees C and to 82.9 degrees C for P(Amor-stat-HPA) and P(DMA-stat-HPA), respectively, at a concentration of 1 wt %. LCST behavior was observed for copolymers with >40 wt % HPA in P(Amor-stat-HPA) and >55 wt % HPA in the P(DMA-stat-HPA) library.