Phase Diagram of Tapered Copolymers Based on Isoprene and Styrene
Phase Diagram of Tapered Copolymers Based on Isoprene and Styrene
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DOI：
10.1002/macp.202200033
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发表时间：
2022-04-04
影响因子：
2.5
通讯作者：
Floudas, George
中科院分区：
文献类型：
--
作者：
Galanos, Eftyxis;Wahlen, Christian;Floudas, George
虽然目前已知通过顺序单体加成制备的嵌段共聚物的几种相图，但相应的锥形共聚物的相图尚未详细报道，尽管后者在工业上具有重要意义。本文报道了苯乙烯和异戊二烯在环己烷中由正丁基锂引发的统计阴离子共聚反应生成的一系列锥形二嵌段共聚物的相图。这种共聚物的聚异戊二烯体积分数f在0.43 f < 0.82范围内，总摩尔质量在46-160 kg mol（-1）范围内。相图由片层、六边形填充柱、弱有序六边形填充柱（CYL）和穿孔（PL）以及不规则双连续形态组成。锥形共聚物的相态与常规序贯单体加成法制得的共聚物相比，既有相似之处，也有明显的不同。结果表明，弱有序的CYL/PL形态构成了相图的很大一部分，与顺序制备的二嵌段共聚物相比，相图明显延长。另一方面，两种体系中双连续形态的组成范围相似（0.64 f(PI) < 0.68）。
Although several phase diagrams of block copolymers prepared by sequential monomer addition are known today, the phase diagrams of the corresponding tapered copolymers have not been reported in detail and this despite the industrial importance of the latter. A phase diagram based on a series of tapered diblock copolymers is reported, generated by the sec-butyllithium initiated statistical anionic copolymerization of styrene and isoprene in cyclohexane. This affords copolymers with polyisoprene volume fractions, f, in the range of 0.43 f < 0.82 and total molar mass in the range of 46-160 kg mol(-1). The phase diagram consists of lamellae, hexagonally packed cylinders, weakly ordered hexagonally packed cylinders (CYL), and perforated (PL) as well as irregular bicontinuous morphologies. The phase state in the tapered copolymers bears some similarities and several distinct differences in comparison to the respective copolymers prepared by conventional sequential monomer addition. It is shown that the weakly ordered CYL/PL morphologies comprise a large part of the phase diagram that is significantly extended in comparison to diblock copolymers prepared sequentially. On the other hand, the composition range for the bicontinuous morphologies is similar in the two systems (0.64 f(PI) < 0.68).