Liu Kun, Ren Lei, He Qing, Xu Wei Jian
Country State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
Macromol Rapid Commun. 2016 May;37(9):752-8. doi: 10.1002/marc.201600009. Epub 2016 Mar 14.
The synthesis and characterization of copolymers from styrene and 1,3-pentadiene (two isomers) are reported. Styrene/1,3-pentadiene (1:1) copolymerization with carbanion initiator yield living, well-defined, alternating (r1 = 0.037, r2 = 0.056), and highly stereoregular copolymers with 90%-100% trans-1,4 units, designed Mn s and low ÐM s (1.07-1.17). The first-order kinetic resolution and NMR spectra demonstrate that the copolymers obtained possess strictly alternating structure containing both 1,4- and 4,1-enchaiments. Also a series of copolymers with varying degrees of alternation are synthesized from para-alkyl substituted styrene derivatives and 1,3-pentadiene. The degree of alternation is strongly dependent on the polarity of solvent, reaction temperature, type of trans-cis isomer of 1,3-pentadiene and para-substituted group in styrene. The macro zwitterion forms (SPC) through the distribution of electronic charges from the donor (1,3-pentadiene) to the acceptor (styrenes) are proposed to interpret the carbanion alternating copolymerization mechanism. Owing to the versatility of the carbanion-initiating reaction, the present alternating strategy based on 1,3-pentadiene (especially cis isomer) can serve as a powerful tool for precise control of polymer chain microstructure, architecture, and functionalities in one-pot polymerization.
报道了苯乙烯与1,3 - 戊二烯（两种异构体）共聚物的合成与表征。苯乙烯/1,3 - 戊二烯（1:1）与碳负离子引发剂的共聚反应生成活性、结构明确的交替共聚物（r1 = 0.037，r2 = 0.056），且具有高度规整性，反式 - 1,4单元含量为90% - 100%，设计的数均分子量（Mn）以及低多分散指数（ÐM）（1.07 - 1.17）。一级动力学拆分和核磁共振谱表明，所得到的共聚物具有严格的交替结构，包含1,4 - 和4,1 - 键接方式。此外，还从对烷基取代的苯乙烯衍生物和1,3 - 戊二烯合成了一系列具有不同交替程度的共聚物。交替程度强烈依赖于溶剂极性、反应温度、1,3 - 戊二烯的反式 - 顺式异构体类型以及苯乙烯中的对位取代基。提出了通过电子从给体（1,3 - 戊二烯）向受体（苯乙烯）的分布形成的宏观两性离子形式（SPC）来解释碳负离子交替共聚反应机理。由于碳负离子引发反应的多功能性，基于1,3 - 戊二烯（尤其是顺式异构体）的当前交替策略可作为在一锅法聚合中精确控制聚合物链微观结构、结构和功能的有力工具。
