A controlled synthesis method of polystyrene-b-polyisoprene-b-poly(methyl methacrylate) copolymer via anionic polymerization with trace amounts of THF having potential of a commercial scale
A controlled synthesis method of polystyrene-b-polyisoprene-b-poly(methyl methacrylate) copolymer via anionic polymerization with trace amounts of THF having potential of a commercial scale
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DOI：
10.1039/c6ra25155b
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发表时间：
2017-01-01
期刊：
影响因子：
3.9
通讯作者：
Zheng, Anna
中科院分区：
文献类型：
--
作者：
Li, Zheng;Chen, Jianding;Zheng, Anna
创新了阴离子共聚聚苯乙烯-b-聚异戊二烯-b-聚甲基丙烯酸甲酯（PS-b-PI-b-PMMA）三嵌段共聚物的可控合成方法，与以往极性单体阴离子聚合研究不同，采用非极性环己烷作为溶剂，仅采用微量四氢呋喃（THF）作为极性调节剂。顺序阴离子共聚可以在0℃下顺利进行，所有单体的转化率达到100%。通过凝胶渗透色谱（GPC）、质子核磁共振（H-1-MNR）、动态力学分析（DMA）和差示扫描量热法（DSC）对共聚物进行了表征。结果发现PS、PI和PMMA的数均分子量(M-n)分别为12 760、26 340和13 600。 PI嵌段中1,4-加成结构占93%，并解释了其形成机制。此外，具有不同长度的PMMA嵌段的三嵌段共聚物的生产证实了该合成方法具有结构明确、副反应少和合适的温度。基于这些结果，商业规模的含有极性单体MMA的阴离子嵌段共聚开始成为可能。
A controlled synthesis method for the polystyrene-b-polyisoprene-b-poly(methyl methacrylate) (PS-b-PI-b-PMMA) tri-block copolymer using the anionic copolymerization was innovated, in which being differ from previous researches for the anionic polymerization of polar monomers, nonpolar cyclohexane was used as solvent and only trace amounts tetrahydrofuran (THF) was adopted as a polar regulator. The sequential anionic copolymerization could be smoothly conducted at 0 degrees C and the conversion of all monomers reached 100%. The copolymer was characterized by gel permeation chromatography (GPC), proton nuclear magnetic resonance (H-1-MNR), dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). It was found that the number average molecular weights (M-n) of PS, PI and PMMA were 12 760, 26 340 and 13 600 respectively. The 1,4-addition structure in PI block occupied 93% and its forming mechanism was explained. Furthermore, the produce of tri-block copolymers with PMMA block of different lengths confirmed this synthesis method controlled for definite structures, fewer side reactions and a appropriate temperature. Based on these results, the anionic block copolymerization containing polar monomer MMA at a commercial scale starts to become possible.