Characterization of Z‐RAFT Star Polymerization of Butyl acrylate by Size‐Exclusion Chromatography
Characterization of Z‐RAFT Star Polymerization of Butyl acrylate by Size‐Exclusion Chromatography
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DOI：
10.1002/masy.200950121
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发表时间：
2009
影响因子：
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通讯作者：
D. Boschmann;R. Edam;P. Schoenmakers;Philipp Vana
中科院分区：
文献类型：
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作者：
D. Boschmann;R. Edam;P. Schoenmakers;Philipp Vana
使用带有丙酸甲酯作为离去基团的多官能三硫代碳酸酯型RAFT试剂进行丙烯酸丁酯的Z-RAFT星星聚合，以形成具有3、4和6个臂的星星聚合物。聚合显示出良好的控制行为，高单体转化率。通过使用单官能和多官能RAFT试剂的混合物，在单个RAFT聚合内同时获得臂和星星聚合物，这使得能够评估表观臂数。发现所需的拓扑结构的星星聚合物已经存在，从聚合的早期阶段上。根据早期报道的星星偶联反应的表观臂数略有增加，在非常高的单体转化率。常规校准的SEC的校正因子显示出与聚苯乙烯星的数据的极好的一致性，表明与线性聚合物相比流体动力学体积的收缩仅取决于聚合物的拓扑结构。然而，星星聚合物的绝对摩尔质量的评估受到常规校准的准确性的限制。
Z-RAFT star polymerization of butyl acrylate using multifunctional trithiocarbonate-type RAFT agents carrying methyl propionate as the leaving group were used to form star polymers having 3, 4, and 6 arms. The polymerizations showed well controlled behavior up to high monomer conversions. By using a mixture of mono- and multifunctional RAFT agents, arm and star polymer were obtained simultaneously within a single RAFT polymerization, which enabled the evaluation of the apparent arm numbers. The desired topology of the star polymers was found being present already from the early phase of polymerization on. The apparent arm number slightly increases at very high monomer conversions in accordance to earlier reported star coupling reactions. Correction factors for conventionally calibrated SEC showed excellent agreement with data for polystyrene stars, indicating that the contraction of the hydrodynamic volume in comparison to linear polymer is only dependent on the polymer topology. The evaluation of absolute molar masses of star polymers was however limited by the accuracy of the conventional calibration.