Abstract Polymerization of norbornene was carried using a (MC) and two dinuclear (DC1 and DC2) α–diimine Ni-based catalysts under controlled conditions. The structure of dinuclear catalysts had a difference on the ortho- and para position (2,4.6-trimethyl group for DC1 and 2, 6-isopropyl group for DC2). DC2 catalyst through synergistic effects exhibited higher productivity (1.3 × 106 g/mol Ni) in comparison to DC1 catalyst (1.0 × 106 g/mol Ni) and MC catalyst (0.8 × 106 g/mol Ni). Moreover, molecular weights of the polynorbornene (PN) made by DC2 catalyst (Mw = 9.0 × 105 g/mol and Mv = 5.1 × 105 g/mol) were greater than the sample obtained by DC1 (Mv = 3.1 × 105 g/mol) and MC (Mw = 4.7 × 105 g/mol and Mv = 2.4 × 105 g/mol). Reaction parameters especially polymerization temperature showed a significant impact on catalyst productivity and molecular weight of the samples. Thermal analysis including DSC, DMTA and TGA employed to characterize the PNs and revealed that the sample obtained by DC2 catalyst had a much uniform and stereoregularity in microstructure, while for MC, results were slightly different. Based on this, the Tg of the PN made by the DC2 catalyst was distinctive, and the DTGA curve was unimodal. The microstructural study of PNs was carried out using 13C NMR and confirmed the observed properties. Graphical Abstract

中文翻译：

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单核和双核α-二亚胺镍基催化剂合成聚降冰片烯的比较及其微观结构研究

摘要 降冰片烯的聚合是在受控条件下使用一种 (MC) 和两种双核（DC1 和 DC2）α-二亚胺镍基催化剂进行的。双核催化剂的结构在邻位和对位上存在差异（DC1为2,4.6-三甲基，DC2为2,6-异丙基）。与 DC1 催化剂（1.0 × 106 g/mol Ni）和 MC 催化剂（0.8 × 106 g/mol Ni）相比，DC2 催化剂通过协同效应表现出更高的生产率（1.3 × 106 g/mol Ni）。此外，由 DC2 催化剂制备的聚降冰片烯 (PN) 的分子量 (Mw = 9.0 × 105 g/mol 和 Mv = 5.1 × 105 g/mol) 大于 DC1 获得的样品 (Mv = 3.1 × 105 g/mol ) 和 MC (Mw = 4.7 × 105 g/mol 和 Mv = 2.4 × 105 g/mol)。反应参数尤其是聚合温度对催化剂的生产率和样品的分子量有显着影响。包括 DSC、DMTA 和 TGA 在内的热分析用于表征 PN，表明 DC2 催化剂获得的样品在微观结构上具有非常均匀和立构规整性，而对于 MC，结果略有不同。基于此，DC2催化剂制备的PN的Tg有区别，DTGA曲线是单峰的。PNs 的微观结构研究是使用 13C NMR 进行的，并证实了观察到的特性。图形概要 结果略有不同。基于此，DC2催化剂制备的PN的Tg有区别，DTGA曲线是单峰的。PNs 的微观结构研究是使用 13C NMR 进行的，并证实了观察到的特性。图形概要 结果略有不同。基于此，DC2催化剂制备的PN的Tg有区别，DTGA曲线是单峰的。PNs 的微观结构研究是使用 13C NMR 进行的，并证实了观察到的特性。图形概要