Addition copolymerization of norbornene lactone catalyzed by Pd complexes,Journal of Polymer Science

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Addition copolymerization of norbornene lactone catalyzed by Pd complexes
Journal of Polymer Science ( IF 3.9 ) Pub Date : 2021-07-01 , DOI: 10.1002/pol.20210310
Kosuke Isaji ₁ , Shin‐ichi Matsuoka ₁ , Masato Suzuki ₁

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The addition copolymerization of norbornene (NB) with functionalized monomers can lead to the modification of physical properties of poly(NB). Herein, the synthesis of new copolymer of NB with exo-norbornene lactone (exo-NBL) is reported. The copolymerization proceeded by four Pd catalytic systems, and of these, Pd(allyl)IDippCl/AgSbF₆ (IDipp = 1,3-bis[2,6-diisopropylphenyl]imidazolin-2-ylidene)) was the most effective for the incorporation of exo-NBL. Specifically, the copolymerization with exo-NBL/NB feed ratio of 50/50 at r.t. by 0.1 mol% of the Pd catalyst produced poly(NB-co-exo-NBL) with M_n of 87,000, and M_w/M_n of 1.2 in 40% yield, incorporating exo-NBL of 18 mol%. The time–conversion plots and ¹H diffusion ordered spectroscopy (DOSY) NMR analysis of the copolymer suggest that it has a random sequence. In contrast, no copolymer was formed from endo-NBL. This is because of steric hindrance of the endo-lactone moiety by considering the (co)polymerization of endo-5-norbornene-2-carboxylic acid methyl ester (endo-NBCO₂Me). The incorporation of exo-NBL improves the solubility of poly(NB-co-exo-NBL) in several chlorinated solvents and gives high thermal stability with 10% weight loss at a temperature of more than 400°C. Two amorphous halos corresponding to intra- and interchain distances were observed in the WAXD patterns, allowing to calculate d-spacing values, which are higher than that of poly(NB).

中文翻译：

Pd配合物催化降冰片烯内酯的加成共聚反应

降冰片烯 (NB) 与官能化单体的加成共聚可导致聚 (NB) 物理性能的改变。本文报道了NB与外-降冰片烯内酯( exo- NBL)的新型共聚物的合成。共聚反应由四种 Pd 催化体系进行，其中，Pd(allyl)IDippCl/AgSbF ₆ (IDipp = 1,3-双[2,6-二异丙基苯基]咪唑啉-2-亚基))是最有效的掺入的外-NBL。具体而言，使用0.1 mol% 的 Pd 催化剂在 rt 下以 50/50 的exo -NBL/NB 进料比共聚产生聚 ( NB - co - exo -NBL)，其M _n为 87,000，和M _w / M _n为 1.2，产率为 40%，包含18 mol% 的exo -NBL。共聚物的时间转换图和¹ H 扩散有序光谱 (DOSY) NMR 分析表明它具有随机序列。相反，没有由内-NBL形成的共聚物。这是因为空间位阻的内通过考虑的（共）聚合内酯部分内-5-降冰片烯-2-羧酸甲酯（内-NBCO ₂ Me）的。exo- NBL的掺入提高了poly(NB- co - exo-NBL) 在几种氯化溶剂中提供高热稳定性，在超过 400°C 的温度下重量损失 10%。在 WAXD 模式中观察到对应于链内和链间距离的两个无定形晕圈，允许计算d间距值，该值高于聚 (NB) 的值。

更新日期：2021-09-01

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