State and Local Joint Engineering Laboratory for Novel Functional, Polymeric Materials, Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
State Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou, 215123, China.
Macromol Rapid Commun. 2021 Sep;42(18):e2000724. doi: 10.1002/marc.202000724. Epub 2021 Jan 26.
Sequence control has attracted increasing attention for its ability of regulating polymer property and performance. Herein, the sequence-controlled polymer containing acrylonitrile (AN) is achieved by using 2,5-dimethylfuran/acrylonitrile adduct as a latent monomer. The temperature-dependent retro Diels-Alder reaction is engaged in controlling the release of AN during RAFT polymerization, that is, regulating the instant AN concentration via a non-invasive and in situ manner. Such control over the instant AN concentration and particularly the molar ratio of comonomer pair leads to the simultaneous change of monomer units in "living" polymeric chain, thus resulting in the sequence-controlled polymeric structures. By delicately manipulating the polymerization temperature, diverse sequence-on-demand structures of AN-containing copolymers, such as poly(AN/methyl methacrylate), poly(AN/styrene), poly(AN/butyl acrylate), poly(AN/N,N-dimethylacrylamide), and poly(AN/N-isopropylacrylamide) are created. Meanwhile, this study presents an initial attempt in tuning the thermal responsivity of poly(AN/N-isopropylacrylamide), which is closely correlated to the sequence of polymer structure. More importantly, the polymer with averagely distributed AN units results in the higher thermal sensitivity. Therefore, the synthetic strategy proposed in this work offers a promising platform for accessing the sequence-controlled copolymers containing AN structures, thus expanding the investigation on the relationship between the polymer structures and correlated properties.
序列控制因其调节聚合物性质和性能的能力而引起了越来越多的关注。在此，通过使用 2,5-二甲基呋喃/丙烯腈加合物作为潜伏单体，实现了含有丙烯腈 (AN) 的序列控制聚合物。温度依赖性逆 Diels-Alder 反应用于控制 RAFT 聚合过程中 AN 的释放，即通过非侵入性和原位方式调节瞬时 AN 浓度。这种对瞬时 AN 浓度的控制，特别是对单体对摩尔比的控制，导致“活性”聚合物链中单体单元的同时变化，从而导致序列控制聚合物结构的形成。通过巧妙地控制聚合温度，可以制备出各种按需序列的含 AN 共聚物结构，如聚（AN/甲基丙烯酸甲酯）、聚（AN/苯乙烯）、聚（AN/丙烯酸丁酯）、聚（AN/N,N-二甲基丙烯酰胺）和聚（AN/N-异丙基丙烯酰胺）。同时，本研究首次尝试调节聚（AN/N-异丙基丙烯酰胺）的热响应性，这与聚合物结构的序列密切相关。更重要的是，具有平均分布的 AN 单元的聚合物导致更高的热灵敏度。因此，本工作中提出的合成策略为获得含有 AN 结构的序列控制共聚物提供了一个有前途的平台，从而扩展了对聚合物结构与相关性能之间关系的研究。
